Large multinational evaluation of time to reintervention in patients undergoing bioprosthetic valve implantation during open heart surgery

Introduction

Bioprosthetic valves are increasingly utilized during open heart surgery in favor of mechanical valves. These tissue valves are prone for structural valve degeneration and failure, especially in young patients. Transcatheter aortic valve implantation (TAVI) is an appealing approach in these patients.

Purpose

To describe independent correlates for early need for reintervention.

Method

We used a large multicenter registry of patients (>45 years of age) with failed bioprosthetic surgical valves undergoing TAVI valve-in-valve (VinV) in either aortic or the mitral positions. Early reintervention was (<5 years between open-heart surgery and VinV). Multi-variable properties that were included: patient gender, age at open-heart surgery, valve size, baseline renal failure, position of valve implantation, and bioprosthetic valve label size.

Results

A total of 3,324 patients were included in the study (age at the time of open heart surgery 68.9+7.9 years). Median time to TAVI was 9 years (IQR 6–13 years). A total of 632 (19%) patients experienced early valve degeneration with median time to TAVI of only 3 years [IQR 1–5]. Patients with early degeneration were older than those without early degeneration (mean age at surgery was 72.8±9 years vs. 68.9±8 years; p<0.001). in addition, significant linear relation between older patient age and early valve degeneration (p for trend <0.001). Re-intervention in the mitral position was more common in the group of patients with early degeneration (24.4% vs 18.2% without early degeneration; p<0.001) Patient age and mitral valve position were independently associated with increased rate of early degeneration (OR 1.09 [1.08–1.11], p<0.001; OR 1.62 [1.31–2.01]; p<0.001 respectively).

Conclusions

In this large multicenter analysis of patients undergoing TAVR for failed bioprosthetic valves we identified old patient age and mitral valve (vs. aortic) as independent correlates for early intervention. A discrepancy with known association of young age and rapid bioprosthetic valve degeneration is to be determined.

Funding Acknowledgement

Type of funding sources: None.

Autologous skin-derived neural precursor cell therapy reverses canine Alzheimer dementia-like syndrome in a proof of concept veterinary trial

BACKGROUND

Older companion dogs naturally develop a dementia-like syndrome with biological, clinical and therapeutic similarities to Alzheimer disease (AD). Given there has been no new safe, clinically effective and widely accessible treatment for AD for almost 20 years, an all-new cell therapeutic approach was trialled in canine veterinary patients, and further modelled in aged rats for more detailed neurobiological analysis.

METHODS

A Phase 1/2A veterinary trial was conducted in N = 6 older companion dogs with definitive diagnosis of Canine Cognitive Dysfunction (CCD). Treatment comprised direct microinjection of 250,000 autologous skin-derived neuroprecursors (SKNs) into the bilateral hippocampus using MRI-guided stereotaxis. Safety was assessed clinically and efficacy using the validated Canine Cognitive Dysfunction Rating Scale (CCDR) at baseline and 3-month post treatment. Intention to treat analysis imputed a single patient that had a surgical adverse event requiring euthanasia. Three dog brains were donated following natural death and histology carried out to quantify Alzheimer pathology as well as immature neurons and synapses; these were compared to a brain bank (N = 12) of untreated aged dogs with and without CCD. Further, an age-related memory dysfunction rat model (N = 16) was used to more closely evaluate intrahippocampal engraftment of canine SKN cells, focusing on mnemonic and synaptic effects as well as donor cell survival, neurodifferentation and electrophysiologic circuit integration in a live hippocampal slice preparation.

RESULTS

Four out-of-five dogs improved on the primary clinical CCDR endpoint, three fell below diagnostic threshold, and remarkably, two underwent full syndromal reversal lasting up to 2 years. At post mortem, synaptic density in the hippocampus specifically was nine standard deviations above non-treated dogs, and intensity of new neurons also several fold higher. There was no impact on AD pathology or long-term safety signals. Modelling in aged rats replicated the main canine trial findings: hippocampally-dependent place memory deficits were reversed and synaptic depletion rescued. In addition, this model confirmed donor cell survival and migration throughout the hippocampus, neuronal differentiation in situ, and physiologically-correct integration into pyramidal layer circuits.

CONCLUSIONS

With further development, SKN cell therapy may have potential for treating carefully chosen AD patients based on neurosynaptic restoration in the hippocampus.

Assessment of paediatric head shape and management of craniosynostosis

BACKGROUND

The presentation of a child with an abnormal head shape can be challenging and should be met with an appropriate clinical approach. Craniosynostosis is a common cause of paediatric skull deformity and is best managed by a multispecialty tertiary referral unit with regular follow-up. As craniosynostosis frequently requires time-sensitive surgery, it is important to differentiate between craniosynostosis and common self-limiting conditions such as deformational plagiocephaly.

OBJECTIVE

The aim of this article is to outline the clinical approach to paediatric skull deformity in the general practice setting, and to highlight the importance of early referral if there is clinical suspicion of craniosynostosis.

DISCUSSION

Parental concern regarding infant head shape is common. General practitioners (GPs) have an important role in assessment, diagnosis and referral for paediatric skull deformities. GPs are well placed to clinically differentiate between deformational plagiocephaly and craniosynostosis and provide timely referrals to optimise patient outcomes.

Telehealth in surgery: an umbrella review

BACKGROUND

Telehealth use has increased worldwide during the COVID-19 pandemic. However, hands-on requirements of surgical care may have resulted in slower implementation. This umbrella review (review of systematic reviews) evaluated the perceptions, safety and implementation of telehealth services in surgery, and telehealth usage in Australia between 2020 and 2021.

METHODS

PubMed was searched from 2015 to 2021 for systematic reviews evaluating real-time telehealth modalities in surgery. Outcomes of interest were patient and provider satisfaction, safety, and barriers and facilitators associated with its use. Study quality was appraised using the AMSTAR 2 tool. A working group of surgeons provided insights into the clinical relevance to telehealth in surgical practice of the evidence collated.

RESULTS

From 2025 identified studies, 17 were included, which were of low to moderate risk of bias. Patient and provider satisfaction with telehealth was high. Time savings, decreased healthcare resource use and lower costs were reported as key advantages of the service. Inability to perform comprehensive examinations was noted as the primary barrier. In Australia, peak telehealth usage coincided with the introduction of temporary telehealth services and increased lockdown measures.

CONCLUSIONS

Patients and providers are broadly satisfied with telehealth and its benefits. Barriers may be overcome via multidisciplinary collaboration. Telehealth may benefit surgical care long-term if implemented correctly both during and after the COVID-19 pandemic.

Genetic and treatment-related risk factors associated with external apical root resorption (EARR) concurrent with orthodontia

OBJECTIVE

As genetic variation accounts for two-thirds of the variation in external apical root resorption (EARR) concurrent with orthodontic treatment, we analyzed the association of selected genetic and treatment-related factors with EARR concurrent with orthodontic treatment.

SETTING AND SAMPLE POPULATION

This case-control study of 134 unrelated, orthodontically treated Caucasian individuals was conducted in part at an Indiana Private Practice, Indiana University and the University of Kentucky.

METHODS

Utilizing a research data bank containing information from ~1450 orthodontically treated patients, pre- and post-treatment radiographs from 460 individuals were evaluated for EARR of the four permanent maxillary incisors. Sixty-seven unrelated Caucasians with moderate to severe EARR were identified and were age-/sex-matched with orthodontically treated Caucasian controls yielding 38 females and 29 males per group. Factors tested for an association with EARR included the following: 1) treatment duration, 2) extraction of maxillary premolars, 3) numerous cephalometric measurements, and 4) DNA polymorphisms within/near candidate genes in a pathway previously implicated in EARR such as the purinergic-receptor-P2X, ligand-gated ion channel 7 (P2RX7; rs208294, rs1718119, and rs2230912), caspase-1 (CASP1; rs530537, rs580253, and rs554344), interleukin-1 beta (IL1B; rs1143634), interleukin-1 alpha (IL1A; rs1800587), and interleukin-1 receptor antagonist (IL1RA; rs419598) genes. Stepwise logistic regression was utilized to identify the factors significantly associated (significance taken at or less than the layered Bonferroni correction alpha) with the occurrence of EARR.

RESULTS

A long length of treatment and the presence of specific genotypes for P2RX7 SNP rs208294 were significantly associated with EARR.

CONCLUSION

EARR occurrence was associated with both genetic and treatment-related variables, which together explained 25% of the total variation associated with EARR in the sample tested.

A Review of Clinical Outcomes for Gait and Other Variables in the Surgical Treatment of Idiopathic Normal Pressure Hydrocephalus

BACKGROUND

Idiopathic normal pressure hydrocephalus (INPH) is a treatable cause of gait disturbance, cognitive impairment, and urinary incontinence. This clinical triad of symptoms occurs in association with ventriculomegaly and normal cerebrospinal fluid (CSF) pressure. Although the treatment outcomes after CSF shunting for INPH have improved significantly since its first description in 1965, shortcomings in our understanding still remain. Not all INPH patients exhibit clinical improvement after shunting, and it is challenging to identify patients who are more likely to benefit from shunting.

METHODS

The Cochrane Library, Medline, Embase, and PubMed databases were searched for English-language publications between 1965 and October 2015. Reference lists of publications were also manually searched for additional publications.

RESULTS

The findings of this review indicate that, despite efforts to improve patient selection, the degree of clinical improvement after shunting continues to demonstrate significant variability both within and between studies. These discrepancies in treatment outcomes are the result of controversies in 3 distinct but interrelated domains: the underlying pathophysiology of INPH, the diagnosis of INPH, and the identification of likely shunt-responders.

CONCLUSIONS

This review focuses on these 3 areas and their relation to surgical treatment outcomes. Despite the limitations of published outcome studies and limitations in our understanding of INPH pathophysiology, shunting is a safe and effective means of achieving meaningful clinical improvement in most patients with INPH.

Use of external orthotic helmet therapy in positional plagiocephaly

Positional plagiocephaly is the most common type of cranial asymmetry affecting infants. We aimed to investigate the effectiveness of helmet therapy compared to no helmet therapy in treating positional plagiocephaly in infants under the age of 1year. This retrospective review was conducted in an Australian paediatric hospital and included 171 patients recruited from outpatient clinics. Only 30 patients had positional plagiocephaly scores recorded at first and final consultations while 39 patients had diagonal measurements recorded at both visits. The mean age was 7.38months at initial consultation with a mean follow-up duration of 5.85months. Those who had helmet therapy had a significantly greater reduction in diagonal difference than those who did not use helmets (p=0.011). Therefore, there may be a role for helmet therapy in the treatment of severe positional plagiocephaly.

Knee arthroscopy routines and practice

PURPOSE

Knee arthroscopy is one of most commonly performed day-case orthopaedic procedures, thus consuming huge medical resources. The aim of the present questionnaire survey was to study knee arthroscopy routines and practice.

METHODS

An electronic web-based survey including questions around pre-, per- and postoperative routines for elective knee arthroscopy was send to all orthopaedic units associated to the Swedish Arthroscopic Society (n = 60).

RESULTS

Responses covering 37 centres out of 60 (response rate 62%) were returned. Preoperative radiograph routines varied considerable between centres; conventional radiograph varied between 5 and 100% and preoperative MRI between 5 and 80% of patients. General anaesthesia was the preferred intra-operative technique used in all centres (median 79% of patients), local anaesthesia with or without light sedation was used in all 28 out of the 37 centres responding (median 10% of cases) and spinal anaesthesia was used in 15 centres (median 5% of cases). Intra-articular local anaesthesia was provided in all but one of centres. Perioperative administration of oral NSAIDs was common (31 out 37), 6 centres (all teaching hospitals) did not routinely give pre- or postoperative NSAID. Analgesic prescription was provided on a regular base in 18 (49%) of centres; an NSAID being the most commonly prescribed. All but one centre provided written information and instruction at discharge. Referral to physiotherapy, prescribed sick leave and scheduled follow-up in the outpatient clinic diverged considerably.

CONCLUSION

Routines and practice associated to elective knee arthroscopy differed; however, no clear differences in practice were seen between teaching centres, general or local hospitals apart from a lower usage of NSAID for perioperative analgesia. There is an obvious room for further standardisation in the routine handling of patients undergoing elective arthroscopy of the knee.

Treatment of a pontine neuroepithelial cyst by placement of a cystocisternal grommet

We describe an 8-year-old girl who presented with cranial nerve compression due to a brainstem cyst adjacent to the fourth ventricle and describe the first documented insertion of a grommet to form a conduit between a neuroepithelial cyst and ventricle. The patient presented with diplopia and headaches and was found to have the cystic lesion in the right pons. The patient underwent craniotomy, aspiration and fenestration with subsequent recurrence 8 months later. Definitive treatment involved insertion of a grommet. Surgical treatment of symptomatic neuroepithelial cysts can achieve full resolution of neurological deficits. Insertion of a grommet, as distinct from a shunt or fenestration procedure, has the potential to provide long-term resolution of these symptoms without recurrence.

Resolution of hydrocephalus-associated sensorineural hearing loss after insertion of ventriculoperitoneal shunt

The authors present a pediatric patient with severe hearing loss due to communicating hydrocephalus. This is the first clearly documented case of de novo sensorineural deafness caused by hydrocephalus, with subsequent improvement in hearing after shunt insertion. The patient initially presented with otitis media and was found to have hearing loss. After reporting ongoing headaches, he received a diagnosis of communicating hydrocephalus, which was treated with the insertion of a ventriculoperitoneal shunt. Formal hearing tests showed dramatic improvement postsurgery; his hearing was normal at 2 months. At 3 years postsurgery the patient's hearing remains within normal limits. Hearing loss is a rare complication of hydrocephalus. Based on this case, the authors suggest that the diagnosis of hydrocephalus be considered as a cause of unexplained hearing loss, and conversely, that patients with hydrocephalus might benefit from hearing assessment.

Phase III, randomized, double-blind study of elesclomol and paclitaxel versus paclitaxel alone in stage IV metastatic melanoma (MM)

LBA9012

Background: Elesclomol is an investigational first-in-class oxidative stress inducer that increases oxidative stress in cancer cells leading to mitochondria-induced apoptosis. Methods: Patients (pts) with Stage IV MM, no prior chemotherapy, LDH μ 2× ULN were randomized (1:1) to either 213 mg/m2 elesclomol in combination with 80 mg/m2 paclitaxel (ELPAC) or 80 mg/m2 paclitaxel alone (P); both were given weekly ×3 followed by 1 week rest until disease progression. Pts were stratified by prior non-cytotoxic treatment, M1 grade, and LDH. The primary endpoint was PFS with >90% power to detect a 2-month improvement. The primary PFS analysis was planned once all pts had been enrolled and at least 164 PFS events had occurred. Results: 651 pts were enrolled between September 2007 and February 2009. Prognostic factors were generally well balanced. PFS analysis was based on investigator assessment of 411 pts (219 events). Median PFS was 3.5 m (95% CI 2.7–3.7) in ELPAC and 1.9 m (95% CI 1.9–3.3) in P [HR 0.88; 95% CI 0.67–1.16, p=0.3695]. The median number of cycles was 3 in ELPAC and 2 in P. Safety analysis showed increased signals on ELPAC including increased ≥Gr 3 AEs (N=405, 32.8% vs. 23.5%), increased AEs leading to death (N=405, 3.5% vs <1%) and increased overall deaths (N=651, 80 vs 53; 80% censored). Most common AEs in ELPAC were fatigue (32.8%), alopecia (31.3%) and nausea (27.9%). Conclusions: There was an improvement in PFS in the ELPAC arm, but it did not achieve statistical significance. In February 2009, the study was halted based on the recommendation of the DMC to unblind the study after the DMC observed increased deaths on the ELPAC arm. The DMC could not determine whether the observed increased deaths were treatment related or not. Of note, in this analysis there were no specific target organ toxicities attributable to ELPAC that could explain the imbalance of deaths. OS data continues to be collected to determine if the observed imbalance in OS persists as the data mature.

[Table: see text]

Phase III, randomized, double-blind study of elesclomol and paclitaxel versus paclitaxel alone in stage IV metastatic melanoma (MM)

LBA9012

The full, final text of this abstract will be available in Part II of the 2009 ASCO Annual Meeting Proceedings, distributed onsite at the Meeting on May 30, 2009, and as a supplement to the June 20, 2009, issue of the Journal of Clinical Oncology.

[Table: see text]

Models of the pulsatile hydrodynamics of cerebrospinal fluid flow in the normal and abnormal intracranial system

Images obtained from magnetic resonance imaging have helped to ascertain that both the cerebrospinal fluid (CSF) and brain move in a pulsatile manner within the cranium. However, these images are not able to reveal any quantitative information on the physiological forces that are associated with pulsatile motion. Understanding both the pressure and velocity flow field of CSF in the ventricles is important to help understand the mechanics of hydrocephalus. Four separate fluid structure interaction models of the ventricular system in the sagittal plane were created for this purpose. The first model was of a normal brain. The second and third models were pathological brain models with aqueductal stenosis at various locations along the fluid pathway. The fourth model was of a hydrocephalic brain. Results revealed the hydrodynamics of CSF pulsatile flow in the ventricles of these models. Most importantly, it has also revealed the different changes in CSF pulsatile hydrodynamics caused by the various locations of fluid flow obstructions.

Subgroup analysis of efficacy and safety analysis of a randomized, double-blinded controlled phase II study of STA-4783 in combination with paclitaxel in patients with metastatic melanoma

8528

Background: STA-4783 (S), an inducer of heat shock protein 70 (hsp70) is a bis-thiobenzoylhydrazide compound. S leads to up-regulation of hsp70 in tumor cell lines. Xenograft models of solid tumors showed synergistic anti-tumor activity in combination with paclitaxel (P). The combination P + S, in phase I and II studies, showed dose-related hsp70 induction (evidence of biological activity) and tolerability. Methods: Eligibility was based on a diagnosis of metastatic cutaneous melanoma, ECOG <=2, and prior treatment with 1 or no chemotherapy regimens. A total of 81 patients (pts) were randomized 2:1 (P 80 mg/m2 + S 213 mg/m2:P 80 mg/m2) 3 weeks out of 4 at 21 US clinical sites. The primary endpoint was progression free survival (PFS); secondary endpoints were response rate (RR), and adverse events (AEs). Results: Based on intent-to-treat analysis, the median PFS was 3.68 months (m) for P + S vs. 1.84 m in the P only arm (p=.035). RR was 15.1% in the P + S arm and 3.6% in the P arm. Subgroup analysis showed chemo- naive pts (n=23) with P + S showed a median PFS of 8.28 m vs. 2.40 in the P arm (n=9). For pts with 1 prior chemotherapy, (n=29), PFS on P + S was 3.12 m vs. 1.77 m on P (n=19). Of 19 pts who crossed over at progression, data are available for 14. PFS ranged from 0.72 to 5.5 m. Three of the 14 evaluable pts treated with P alone had rapid progression (0.95, 1.6, and 1.7 m) then significant inversion of the time to progression with the addition of S to P (2.3, 5.5, and 4.2 m) suggesting study drug effect. Scans were done at identical intervals (8 weeks). The proportion of pts with AEs of grade 3 or higher was 54% (n=52) in the P + S group and 57% in the P group (n=28); pts on P received a median of 2 cycles, while pts in the P + S group received a median of 4. Adverse events leading to discontinuation were low in both groups: 10% for the P + S, and 14% for P. Conclusions: The addition of S to P showed an increase in PFS vs. P alone particularly in chemo-naïve pts. A few pts failing single agent P appeared to benefit from P + S. Despite the additional treatment duration in the P + S group the drugs were well- tolerated, and showed mainly P related adverse events. A phase III study is planned to confirm a role for P + S in metastatic melanoma.

[Table: see text]

Mantle Cell Lymphoma Disguised as Marginal Zone Lymphoma

We report a case of mantle cell lymphoma histologically indistinguishable from marginal zone lymphoma. An 83-year-old man presented with a 9.0-cm, slowly enlarging axillary mass. Microscopically, the neoplastic process was largely interfollicular, surrounding residual follicular centers, some of which had discernible small lymphocyte mantles. Overall, the morphologic pattern was highly suggestive of marginal zone lymphoma. However, flow cytometric and immunohistochemical results, including cyclin D1 positivity, revealed an immunophenotype that fit with mantle cell lymphoma. The differential diagnosis of mantle cell lymphoma is broad, and it is well known that mantle cell lymphoma can assume a number of histologic appearances, including, infrequently, that of more indolent B-cell non-Hodgkin lymphomas. Although not pathognomonic, cyclin D1 positivity is highly specific for mantle cell lymphoma and is key in distinguishing these clinically dissimilar malignant lymphomas. In recent years, detection of cyclin D1 has expanded the recognizable histologic spectrum of mantle cell lymphoma.

The placebo effect in irritable bowel syndrome trials: a meta-analysis

BACKGROUND

Despite the apparent high placebo response rate in randomized placebo-controlled trials (RCT) of patients with irritable bowel syndrome (IBS), little is known about the variability and predictors of this response.

OBJECTIVES

To describe the magnitude of response in placebo arms of IBS clinical trials and to identify which factors predict the variability of the placebo response.

METHODS

We performed a meta-analysis of published, English language, RCT with 20 or more IBS patients who were treated for at least 2 weeks. This analysis is limited to studies that assessed global response (improvement in overall symptoms). The variables considered as potential placebo modifiers were study design, study duration, use of a run-in phase, Jadad score, entry criteria, number of office visits, number of office visits/study duration, use of diagnostic testing, gender, age and type of medication studied.

FINDINGS

Forty-five placebo-controlled RCTs met the inclusion criteria. The placebo response ranged from 16.0 to 71.4% with a population-weighted average of 40.2%, 95% CI (35.9-44.4). Significant associations with lower placebo response rates were fulfillment of the Rome criteria for study entry (P=0.049) and an increased number of office visits (P=0.026).

CONCLUSIONS

Placebo effects in IBS clinical trials measuring a global outcome are highly variable. Entry criteria and number of office visits are significant predictors of the placebo response. More stringent entry criteria and an increased number of office visits appear to independently decrease the placebo response.

The placebo effect in irritable bowel syndrome trials: a meta-analysis

BACKGROUND

Despite the apparent high placebo response rate in randomized placebo-controlled trials (RCT) of patients with irritable bowel syndrome (IBS), little is known about the variability and predictors of this response.

OBJECTIVES

To describe the magnitude of response in placebo arms of IBS clinical trials and to identify which factors predict the variability of the placebo response.

METHODS

We performed a meta-analysis of published, English language, RCT with 20 or more IBS patients who were treated for at least 2 weeks. This analysis is limited to studies that assessed global response (improvement in overall symptoms). The variables considered as potential placebo modifiers were study design, study duration, use of a run-in phase, Jadad score, entry criteria, number of office visits, number of office visits/study duration, use of diagnostic testing, gender, age and type of medication studied.

FINDINGS

Forty-five placebo-controlled RCTs met the inclusion criteria. The placebo response ranged from 16.0 to 71.4% with a population-weighted average of 40.2%, 95% CI (35.9-44.4). Significant associations with lower placebo response rates were fulfillment of the Rome criteria for study entry (P=0.049) and an increased number of office visits (P=0.026).

CONCLUSIONS

Placebo effects in IBS clinical trials measuring a global outcome are highly variable. Entry criteria and number of office visits are significant predictors of the placebo response. More stringent entry criteria and an increased number of office visits appear to independently decrease the placebo response.

A 59-Year-Old Woman With Immunotactoid Glomerulopathy, Heavy-Chain Disease, and Non-Hodgkin Lymphoma

Immunotactoid glomerulopathy is one of several renal disorders characterized by the extracellular deposition of nonamyloid fibrillary deposits. There is considerable debate as to whether immunotactoid glomerulopathy should be distinguished from fibrillary glomerulonephritis, a closely related entity. Currently, the distinction is based on fibril size and arrangement. We report the case of a 59-year-old woman in whom a diagnosis of immunotactoid glomerulopathy was made after a 2-year history of proteinuria. Electron microscopy of her renal biopsy showed randomly arranged microtubular subepithelial and mesangial deposits, which measured 34 nm in average diameter. She was later discovered to have circulating immunoglobulin G heavy chains without associated light chains (γ-heavy-chain disease) and, subsequently, non-Hodgkin lymphoma, follicular lymphoma, grade I (World Health Organization classification). Approximately 100 cases of γ-heavy-chain disease have been reported in the literature since it was originally described by Franklin in 1964. However, while there are 10 reports in the literature of heavy-chain disease with fibrillary deposits in the kidney, none fit the criteria for immunotactoid glomerulopathy.

Frequency tuning of input-output relation in a rat cortical neuron in-vitro

The input-output relation of a single neuron stands at the basis of every biologically oriented description of the brain. This report shows that the input-output relation of cultured cortical neurons is non-linearly tuned by the input frequency. Increasing the rate of stimulation results in the appearance of ordered temporal firing patterns, which are qualitatively different for different input frequencies. The experimental results of this study lead to the conclusion that frequency tuning of neuronal input-output relation arises from activity-dependent rates at the molecular level underlying the mechanism of excitability itself.

Aural-pharyngeal polyps associated with Cryptosporidium infection in three iguanas (Iguana iguana)

Cryptosporidium spp. infection was associated with aural-pharyngeal polyps in three iguanas (Iguana iguana). All iguanas were presented for masses protruding from the ear canal, and the disease was characterized by a chronic clinical course. The masses consisted of nests of cystic glands surrounded by abundant fibrous connective tissue and lined by hyperplastic cuboidal to pseudostratified columnar epithelium that was moderately to heavily colonized by cryptosporidial organisms. Electron microscopy revealed that the majority of organisms were trophozoites.

Proliferative osteoarthritis and osteoarthrosis in 15 snakes

Fifteen snakes representing seven species with segmental, proliferative osteoarthritis and osteoarthrosis of the spine were presented for examination. All the snakes were captive, privately owned, and fed domestic rodents. Physical examination, radiography, blood culture, bone culture, necropsy, and histopathology were performed on each snake. All the snakes had similar physical examination, radiologic, and necropsy findings. There were three histologic types of lesions: active bacterial osteoarthritis, predominantly noninflammatory osteoarthrosis with multifocal inflammation suggestive of chronic bacterial osteoarthritis, and noninflammatory lesions consistent with osteoarthrosis without evidence of inflammation or bacteria. These findings suggest that all these snakes represent a single disease process, bacterial infection of the vertebrae. The different histologic lesions observed in these snakes may be a continuum of lesions, from acute to chronic. Gram-negative bacteria were isolated from the blood or bone lesions of 8 of the 15 snakes. In six of these eight snakes, Salmonella species were isolated. Gram-positive bacteria (Streptococcus sp.) were isolated from two other snakes. Blood and bone culture results were well correlated, so blood culture may be effective for detecting active bacterial osteoarthritis.

Can local anesthesia be recommended for routine use in elective knee arthroscopy? A comparison between local, spinal, and general anesthesia

Local anesthesia (LA) for outpatient knee arthroscopy is not a standard procedure at most hospitals. To evaluate the LA technique for knee arthroscopy on medically healthy patients, this study compared 3 anesthesia techniques. Four hundred patients were randomized to either local (n = 200), general (n = 100), or spinal (n = 100) anesthesia. Evaluated outcomes included the patient's subjective view of the procedure, and nausea and pain at rest and during active movement. All variables were recorded perioperatively and postoperatively. In addition, the performing surgeon's opinion of the degree of patient pain and the technical difficulty of the procedure were noted. Three hundred forty-two patients completed the study. In the group receiving local anesthesia (n = 180) the median visual analog scale pain score during surgery was 6 mm (mean, 17.5; SD, 23.2; range, 0 to 100 mm). Twenty-one LA patients would have preferred another form of anesthesia. In 29 patients, LA was not considered as the optimal anesthesia by the performing surgeon. Eight LA patients agreed with the surgeon that the anesthesia method used was not optimal, of these patients, 5 had synovitis (3%). In 5% of the LA patients there were technical problems. Thus, this study shows that elective knee arthroscopy can be performed under local anesthesia in 92% of the patients from a technical point of view. Excluding patients who do not choose local anesthesia and those who have hypertrophic synovitis preoperatively, knee arthroscopies can be performed as safely and effectively under local anesthesia as under any other form of anesthesia. For most patients, local anesthesia can be recommended as the standard procedure for outpatient knee arthroscopy.

Phase I trial of intravenous thymidine and carboplatin in patients with advanced cancer

PURPOSE

To evaluate the biologic interactions and toxicities of carboplatin combined with a 24-hour infusion of thymidine 75 mg/m(2) in a phase I trial.

PATIENTS AND METHODS

Thirty-two patients with cancer refractory to conventional therapy were treated. The first set of patients (n = 7) received thymidine alone 4 weeks before subsequent planned courses of thymidine combined with carboplatin followed (4 weeks) by carboplatin alone. Carboplatin was administered over 20 minutes at hour 20 of the 24-hour thymidine infusion. The carboplatin dose was escalated in patient groups: 200 mg/m(2) (n = 3); 300 mg/m(2) (n = 7); 350 mg/m(2) (n = 4); 400 mg/m(2) (n = 3); 480 mg/m(2) (n = 10); and 576 mg/m(2) (n = 5). At the maximum-tolerated dose (480 mg/m(2)), five patients received combined therapy first and carboplatin alone second, and five patients received carboplatin first and combined therapy second. Maintenance therapy for stable or responding patients was combined therapy.

RESULTS

Evaluation demonstrated a trend toward thymidine protection of carboplatin-induced treatment-limiting thrombocytopenia. Neutropenia with carboplatin alone or in combination was negligible. Thymidine alone had no myelosuppressive effects and produced reversible grade 1 or 2 nausea and vomiting (57%), headache (25%), and grade 1 neurotoxicity (22%). Thymidine did not enhance expected carboplatin toxicities. There was no therapy-related infection or bleeding. Analysis of platinum in plasma ultrafiltrate and urine showed no effect by thymidine. Similarly, thymidine pharmacokinetics was not affected by carboplatin. As predicted, nicotinamide adenine dinucleotide levels in peripheral lymphocytes were increased during exposure to carboplatin and/or thymidine but were decreased by carboplatin alone. In three patients with high-grade glioma, responses included one complete remission (21 months) and one partial remission (14 months) at the 480-mg/m(2)-dose level, and disease stabilization (7 months) at the 400-mg/m(2-dose) level. A minor response was observed in a patient with metastatic colon cancer (5 months) at the 480-mg/m(2)-dose level.

CONCLUSION

The combination of carboplatin and thymidine as described is well tolerated. The data presented have resulted in a phase II study by the North American Brain Tumor Consortium.

Antioxidant status of children with steroid-sensitive nephrotic syndrome

Eighteen children with steroid-sensitive nephrotic syndrome (SSNS) were studied. The control group comprised 20 healthy children. The following indirect parameters of reactive oxygen species activity were determined in nephrotic patients during four stages of the disease (full relapse before prednisone administration, disappearance of proteinuria, prednisone cessation, unmaintained remission): plasma malondialdehyde (MDA) levels, copper/zinc superoxide dismutase (CuZn SOD) activity and glutathione peroxidase (GPX) activity in erythrocytes, reduced glutathione (GSH) and vitamin C levels in whole blood, and vitamin E level in serum. Increased MDA levels, reduced vitamin C levels, and enhanced CuZn SOD activity were found in relapse. GSH concentration was high during all four stages. Vitamin E level was also increased, parallel to the pattern of serum lipids. GPX activity remained low during the proteinuria stage and in remission. We conclude that the majority of abnormal findings can be attributed to the hyperlipidemia of NS. Low GPX activity may be a factor limiting the antioxidant capacity in NS. The present study is inconclusive regarding the role of free radicals in the proteinuria of NS.

The acquired Chiari malformation and syringomyelia following spinal CSF drainage: a study of incidence and management

Firstly, 14 patients are described who developed either an acquired Chiari malformation (ACM) alone (7 cases) or ACM and syringomyelia (7 cases) after lumbar subarachnoid space (SAS) shunting or in one case, epidural anaesthesia with SAS penetration. Four groups are considered: 3 cases with craniofacial dysostosis and communicating hydrocephalus (CH), 4 cases with CH alone, 3 cases with pseudotumour cerebri (PTC) and a miscellaneous group (4 cases). Initial treatment was varied: resiting the shunt to ventricle or cisterna magna [6], adding an H-V valve [1], syrinx shunting [4] and posterior fossa decompression [3]. Further treatment was required in 6 cases. Secondly, incidence was examined in 87 patients with PTC initially treated either by lumbar SAS shunting [70] or cisterna magna shunting [17]. In the first sub-group, 11 cases (15.7 per cent) developed an ACM, 3 symptomatic (as above) and eight asymptomatic with 1 case also having syringomyelia whereas 1 case occurred in the second group with a questionanably symptomatic ACM. While accurate for symptomatic lesions, these figures are tentative with respect to asymptomatic lesions due to inadequate pre-treatment radiology and detailed MR follow-up. The main conclusions are, first, that the incidence of symptomatic ACM and/or syringomyelia is not high enough to warrant abandoning SAS shunting; second that asymptomatic lesions need not necessarily be treated and third, that when treatment is required, shunt resiting is the first choice.

Characterization of prostate-specific antigen proteolytic activity on its major physiological substrate, the sperm motility inhibitor precursor/semenogelin I

The protease prostate-specific antigen (PSA) is a marker widely used clinically for monitoring prostatic malignancies. Under normal conditions, this enzyme is mainly involved in the post ejaculation degradation of the major human seminal protein, the seminal plasma motility inhibitor precursor/semenogelin I (SPMIP/SgI), which is the predominant protein component of human semen coagulum. PSA primary structure and activity on synthetic substrates predict a chymotrypsin-like activity whose specificity remains to be established. The present study was aimed at characterizing the proteolytic processing of the SPMIP/SgI by PSA. Purified SPMIP/SgI was incubated with PSA in the presence or absence of protease inhibitors. General serine protease inhibitors, heavy metal cations (Zn2+ and Hg2+), and the heavy metal chelator 1,10-phenanthroline partially or totally inhibited the proteolytic activity of PSA toward SPMIP/SgI. Under identical conditions, other proteins, such as bovine serum albumin, ovalbumin, and casein, were very poor substrates for PSA. Hydrolysis products were separated by reverse-phase high-performance liquid chromatography, assayed for sperm motility inhibitory activity, and analyzed by immunoblotting and mass spectrometry. The region responsible for the sperm motility inhibitory activity and containing an SPMI antiserum epitope was localized to the N-terminal portion of the molecule between residues 85 and 136. On the other hand, a monoclonal antibody against a seminal vesicle-specific antigen (MHS-5) recognized fragments derived from the central part of the SPMIP/SgI (residues 198-223). PSA hydrolysis occurred almost exclusively at either leucine or tyrosine residues, demonstrating directly for the first time a restricted chymotrypsin-like activity on a physiological substrate. The results suggest that PSA is the main enzyme responsible for the processing of SPMIP/SgI in human semen and that this protease manifests unusual specificity with respect to hydrolyzable substrates and sites of hydrolysis.

Cloning and functional characterization through antisense mapping of a kappa 3-related opioid receptor

We have identified a putative opioid receptor from mouse brain (KOR-3), belonging to the G protein-coupled receptor family, that is distinct from the previously cloned mu, delta, and kappa 1 receptors. Assignment of the clone to the opioid receptor family derives from both structural and functional studies. Its predicted amino acid sequence is highly homologous to that of the other opioid receptors, particularly in many of the transmembrane regions, where long stretches are identical to mu, delta, and kappa 1 receptors. Both cyclazocine and nalorphine inhibit cAMP accumulation in COS-7 cells stably expressing the clone. Northern analysis shows that the mRNA is present in brain but not in a number of other organs. Southern analysis suggests a single gene encoding the receptor. A highly selective monoclonal antibody directed against the native kappa 3 receptor recognizes, in Western analysis, the clone expressed in COS-7 cells. The in vitro translation product is also labeled by the antibody. Additional clones reveal the presence of several introns, including one in the second extracellular loop and another in the first transmembrane region. Antisense studies with an oligodeoxynucleotide directed against a region of the second extracellular loop reveal a selective blockade of kappa 3 analgesia in vivo that is not observed with a mismatch oligodeoxynucleotide based upon the antisense sequence. The mu, delta, and kappa 1 analgesia is unaffected by this antisense treatment. Antisense mapping of the clone downstream from the splice site in the first transmembrane region reveals that six different antisense oligodeoxynucleotides all block kappa 3 analgesia. In contrast, only one of an additional six different antisense oligodeoxynucleotides directed at regions upstream from this splice site is effective. This strong demarcation between the two regions raises the possibility of splice variants of the receptor. An additional clone reveals an insert in the 3' untranslated region. In conclusion, the antibody and antisense studies strongly associate KOR-3 with the kappa 3-opioid receptor, although it is not clear whether it is the kappa 3 receptor itself or a splice variant.

Malignant transformation of angiomyolipoma

Angiomyolipomas are well recognized but uncommon tumors that can involve the kidney. To our knowledge a well documented case of malignant change of angiomyolipoma has never been reported. We report a case of renal angiomyolipoma and leiomyosarcoma with a clearly identified transition of benign to malignant elements seen in the resected tissue.

The effects of ambient temperature on amikacin pharmacokinetics in gopher tortoises

The pharmacokinetics of amikacin were compared in two groups of tortoises, one held at 20 degrees C and the other at 30 degrees C. The mean (+/- SD) residence time for amikacin in the 30 degrees C tortoises was 22.67 +/- 0.50 h; significantly (P less than 0.05) less than those held at 20 degrees C (41.83 +/- 3.23 h). There was no significant difference (P greater than 0.05) in the steady-state volume of distribution (Vd(ss] between the tortoises held at 30 degrees C (0.241 +/- 0.520 l/kg) and those held at 20 degrees C (0.221 +/- 0.019 l/kg). The clearance rate was faster (P less than 0.05) in the warmer tortoises (10.65 +/- 2.42 ml/min/kg at 30 degrees C compared to 5.27 +/- 0.152 ml/min/kg at 20 degrees C). These data indicate that while the volume of distribution was approximately the same, amikacin remained in the colder tortoises longer because of its slower elimination. The oxygen consumption and metabolism were measured and found to be lower in the colder tortoises, almost by the same 2:1 ratio as clearance time (Cl), mean residence time (MRT), and area under the curve (AUC). The data derived from this limited study indicated that an appropriate therapeutic dosage regimen for amikacin in gopher tortoises at 30 degrees C is 5 mg/kg given i.m. every 48 h.