Single- and multiple-dose pharmacokinetics of sotalol hydrochloride in healthy cats.

INTRODUCTION/OBJECTIVES: The objective of this study was to describe the single- and multiple-dose pharmacokinetics and urinary elimination of sotalol in healthy cats. ANIMALS: Six adult purpose-bred cats MATERIALS AND METHODS: Cats were administered 2 mg sotalol/kg body weight as a single intravenous bolus and as a single oral dose in a randomized crossover study with a two-week washout period. The same cats then received 3 mg sotalol/kg orally every 12 h for two weeks. Blood samples were collected at predetermined time points for 48 h postdose for quantification of sotalol using ultra-high-pressure liquid chromatography with mass spectrometry. Non-compartmental analysis was used to obtain pharmacokinetic parameters. Data are presented as median (min-max). RESULTS: Following intravenous administration, plasma clearance and volume of distribution were 9.22 mL/min/kg (5.69-10.89 mL/min/kg) and 2175.56 mL/kg (1961-2341.57 mL/kg), respectively. Bioavailability was 88.41% (62.75-130.29) following a single oral dose. Peak plasma concentration (Cmax) and time to Cmax were 0.94 µg/mL (0.45-1.17 µg/mL) and 1.5 h (0.5-4 h) after a single oral dose (2 mg/kg), and 2.29 µg/mL (1.91-2.48 µg/mL) and 1.0 h (0.5-1.5 h) with chronic oral dosing (3 mg/kg), respectively. Elimination half-life was 2.75 h (2.52-4.10 h) and 4.29 h (3.33-5.53 h) for single and chronic oral dosing, respectively. Accumulation index was 1.17 (1.09-1.29) after chronic dosing. Urinary sotalol recovery was 81-108% of the intravenous dose. CONCLUSIONS: Oral sotalol administration resulted in plasma concentrations reportedly efficacious in other species, with good to excellent oral bioavailability. Urinary excretion appears to be a major route of elimination. Following repeated oral dosing, minimal drug accumulation was estimated. Additional studies in cats are recommended due to the possibility of nonlinear kinetics.

Comparison of manual compression, Z-stitch, and suture-mediated vascular closure device techniques in dogs undergoing percutaneous transvenous intervention.

INTRODUCTION/OBJECTIVES: Manual compression has been standard of care for maintaining hemostasis after percutaneous endovascular intervention, but can be time-consuming and associated with vascular complications. Alternative closure methods include the figure-of-eight suture (Z-stitch) and vascular closure device (VCD) techniques. We hypothesized that compared to manual compression, Z-stitch and VCD would significantly reduce time-to-hemostasis after transvenous access, and the proportion of dogs with vascular patency would not differ significantly among treatments. ANIMALS: Forty-six client-owned dogs undergoing percutaneous transvenous interventional procedures. MATERIALS AND METHODS: Dogs with vessel diameter <5 mm were randomized to undergo manual compression or Z-stitch, while those with vessel diameter ≥5 mm were randomized to undergo manual compression, Z-stitch, or VCD. Time-to-hemostasis, bleeding scores, presence of vascular patency one day and two to three months post-procedure, and complications were recorded. Data are presented as median (95% confidence interval). RESULTS: In all 46 dogs, the right external jugular vein was used. Time-to-hemostasis was significantly shorter in the Z-stitch (2.1 [1.8-2.9] minutes) compared to VCD (8.6 [6.1-11.8] minutes; P<0.001) and manual compression (10.0 [10.0-20.0] minutes; P<0.001) groups. Time-to-hemostasis was significantly shorter in the VCD vs. manual compression (P=0.027) group. Bleeding scores were significantly greater at 5 and 10 min (P<0.001 and 0.013, respectively) in manual compression, compared to Z-stitch group. There was no difference in the proportion of dogs with vascular patency between groups (P=0.59). CONCLUSIONS: Z-stitch and VCD are effective venous hemostasis methods after percutaneous transvenous intervention, with Z-stitch providing the most rapid time-to-hemostasis. Both Z-stitch and VCD techniques have low complication rates and effectively maintain vascular patency.

Transcatheter closure of patent ductus arteriosus in 11 dogs and one cat after incomplete or aborted surgical ligation.

OBJECTIVE: To describe the characteristics and outcomes of transcatheter patent ductus arteriosus (PDA) occlusion after incomplete or aborted surgical ligation in dogs and cats. ANIMALS: Twelve client-owned animals (11 dogs and one cat). MATERIALS AND METHODS: This retrospective study describes data from animals with aborted or incomplete surgical PDA ligation that subsequently underwent transcatheter closure using endovascular methods. Patient demographics, reason for incomplete or aborted surgery, complications, and method of transcatheter occlusion were recorded. Data are presented as mean ± standard deviation or median (interquartile range), where appropriate. RESULTS: For all cases, median age at surgery was 12.2 months (4.9-15.1 months) and at catheterization was 15.4 months (8.9-21.9 months), with 79 days (29-209 days) between surgical and interventional procedures. Median weight at catheterization was 4.5 kg (2.5-12.6 kg). Reasons for failed surgical ligation included hemorrhage during ductal dissection in seven dogs, residual flow in four dogs, and inability to identify the ductus in one cat. Transcatheter closure was successfully performed using a canine duct occluder in eight dogs, transarterial coil embolization in two dogs, and transvenous coil embolization in one dog and one cat. Metallic hemoclips partially obscured angiographic findings in three cases with prior surgical hemorrhage but did not prevent transcatheter closure. In all cases, ductal flow was successfully attenuated, with no or trace residual shunting on angiography and complete occlusion the following day on echocardiography. CONCLUSIONS: When surgery is unsuccessful, either owing to hemorrhage or residual flow, transcatheter closure of PDA is feasible, even in small patients.

Atenolol in cats with subclinical hypertrophic cardiomyopathy: a double-blind, placebo-controlled, randomized clinical trial of effect on quality of life, activity, and cardiac biomarkers.

OBJECTIVE: To compare quality of life (QOL) and activity measures between healthy control cats and cats with subclinical hypertrophic cardiomyopathy (HCM), and to evaluate the effect of oral atenolol therapy on QOL, activity, and circulating biomarkers in cats with subclinical HCM. ANIMALS: Thirty-two client-owned cats with subclinical HCM and 27 healthy control cats. METHODS: Owner responses to a QOL questionnaire, circulating cardiac biomarker concentrations, and accelerometer-based activity measures were compared prospectively in cats with and without HCM, and in cats with HCM before and after treatment with oral atenolol (6.25 mg/cat q 12 h) for 6 months. RESULTS: Owner-assessed activity of daily living score was lower in cats with HCM than in cats in controls (p=0.0420). No differences were identified between control cats and cats with HCM for any activity variable. Compared with placebo, treatment with atenolol was associated with a lower baseline-adjusted mean ± SD heart rate (157 ± 30 vs. 195 ± 20 bpm; p=0.0001) and rate-pressure product (22,446 ± 6,237 vs. 26,615 ± 4,623 mmHg/min; p=0.0146). A treatment effect of atenolol on QOL or activity was not demonstrated. CONCLUSIONS: This study failed to identify an effect of subclinical HCM on owner-assessed QOL or activity or a treatment effect of atenolol on these variables at the dosage evaluated. These findings do not support a treatment benefit of atenolol for the goal of symptom reduction in cats with subclinical HCM.

Outcomes after combined percutaneous balloon valvuloplasty and external beam radiation therapy for the treatment of congenital pulmonic stenosis in four dogs.

Valve restenosis after percutaneous balloon pulmonary valvuloplasty (BPV) for the treatment of congenital pulmonic stenosis (PS) may occur in up to 17% of canine cases. Outcomes in dogs with PS that are treated with repeat BPV after restenosis have not been described. The present report details the clinical courses of four dogs with congenital PS, previously treated with conventional BPV and atenolol (n = 4) or atenolol alone (n = 1), two with anomalous, circumpulmonary coronary artery anatomy, which underwent BPV followed immediately by external beam radiation therapy (BPV + EBRT) to prevent valve restenosis. External beam radiation therapy involved five daily fractions of 3.6 Gray to the pulmonic valve. Echocardiographic and clinical follow-up information for 2-4 years after BPV + EBRT is presented. Three dogs experienced long-term reduction in transpulmonic pressure gradient. In one dog, which was treated with conservative BPV + EBRT as first-line therapy, return of transpulmonic pressure gradient to pretreatment levels was noted by 7 months after BPV + EBRT. Although clinical benefit remains unproven, the addition of EBRT to conventional BPV may be a treatment option for dogs experiencing restenosis after BPV or those in which restenosis is considered likely. Further study to evaluate the efficacy and safety of this approach is needed.

Preliminary investigation of orally administered benazepril in horses with left-sided valvular regurgitation.

BACKGROUND: Despite the paucity of data available, orally administered angiotensin-converting enzyme (ACE) inhibitors are empirically used in horses with valvular regurgitation. OBJECTIVE: Evaluate the echocardiographic and hormonal changes in response to oral benazepril in horses with left-sided valvular regurgitation. STUDY DESIGN: Prospective, randomised double-blind, placebo-controlled trial. METHODS: Horses with mitral valve (MR) and/or aortic valve regurgitation (AR) received oral benazepril (n = 6) at a dosage of 1 mg/kg q 12 h or a placebo (n = 5) for 28 days. Echocardiography was performed before drug administration and after 28 days of treatment. Plasma renin activity, serum ACE activity, angiotensin II concentration, aldosterone concentration and biochemical variables were measured before drug administration and after 7 and 28 days of treatment. RESULTS: Relative to baseline, horses treated with benazepril had statistically significant reduction in left ventricular internal diameter in systole (mean difference between groups = -0.97 cm; 95% CI = -1.5 to -0.43 cm), aortic sinus diameter (-0.31 cm; -0.54 to -0.07 cm), and percentage of the aortic annulus diameter occupied by the base of the AR jet (-17.05%; -31.17 to -2.93%) compared with horses receiving a placebo. In addition, horses treated with benazepril had a significantly greater increase in cardiac output (11.95 L/min; 1.17-22.73 L/min) and fractional shortening (7.59%; 3.3-11.88%) compared with horses receiving a placebo. Despite profound serum ACE inhibition, renin activity and concentrations of angiotensin II and aldosterone were not significantly different between treatment groups or among time points. MAIN LIMITATIONS: Very small sample size and short treatment period. CONCLUSIONS: Treatment with oral benazepril resulted in statistically significant echocardiographic changes that might indicate reduced cardiac afterload in horses with left-sided valvular regurgitation. Additional studies with a larger sample size will be necessary to determine if administration of benazepril is beneficial in horses with valvular regurgitation. The Summary is available in Spanish - see Supporting Information.

Attenuation of the blood pressure response to exogenous angiotensin I after oral administration of benazepril to healthy adult horses.

BACKGROUND: Benazepril has been shown to inhibit circulating angiotensin-converting enzyme (ACE) activity in horses but the optimal dosage is unknown. OBJECTIVES: To determine the lowest tested dose of benazepril that results in ≥75% attenuation in the response of arterial blood pressure (BP) to exogenous angiotensin I (ANG-I) administration. STUDY DESIGN: Prospective experimental study. METHODS: A total of 5 healthy horses were instrumented for the direct measurement of BP. Each horse received 4 intragastric doses of benazepril (0.5, 1, 2 and 4 mg/kg bwt) with a washout period of 7 days between doses. Prior to and 2, 12 and 24 h after benazepril administration, each horse received intravenous (i.v.) boluses of ANG-I at 20, 60 and 200 ng/kg. Attenuation of the systolic arterial pressure (SBP) response to ANG-I and serum ACE activity were quantified and expressed as percentage of inhibition. RESULTS: There was a significant effect of benazepril dose (P = 0.004) and time (P = 0.004) on the percentage of inhibition of the systolic pressor response to ANG-I. Regardless of benazepril dose, the percentage of inhibition was significantly greater 2 h after administration of benazepril compared with 12 and 24 h. At an ANG-I dose of 20 ng/kg, the percentage of inhibition after administration of benazepril at 1 mg/kg bwt (46.6 ± 18.9%) was significantly greater than that achieved after 0.5 mg/kg bwt (19 ± 14%) but not significantly different from that achieved at higher doses of benazepril. Benazepril doses ≥1 mg/kg bwt resulted in serum ACE inhibition of at least 90%. MAIN LIMITATIONS: Small sample size and resulting low statistical power. CONCLUSIONS: Attenuation of the rise in SBP in response to ANG-I after administration of benazepril is modest in horses despite adequate serum ACE inhibition. A dose of 1 mg/kg bwt would be recommended for future investigations of benazepril for the management of cardiovascular diseases in horses.

Congestive heart failure caused by transvenous pacemaker lead prolapse and associated right ventricular outflow tract obstruction in a dog.

A 16-year-old dog was presented for cough as well as increased respiratory rate and effort three years after implantation of a single-lead transvenous artificial pacemaker system. Thoracic radiographs and echocardiography disclosed prolapse of the pacemaker lead into the main pulmonary artery, causing severe pulmonary insufficiency and right-sided volume overload. Repositioning of the pacemaker lead led to improvement of pulmonary insufficiency and resolution of the dog's clinical signs and cavitary effusions. This case describes a late complication of pacemaker implantation that may be avoided by appropriate use of the manufacturer-provided anchoring sleeve and avoidance of excessive lead redundancy.

Cardiovascular effects of pimobendan in healthy mature horses.

REASONS FOR PERFORMING STUDY: Pimobendan is an inodilator used in dogs for the management of heart failure due to myxomatous valve disease or dilated cardiomyopathy. The lack of data regarding the effects of pimobendan in horses prevents the rational use of this drug. OBJECTIVE: To determine the cardiovascular effects of pimobendan in healthy mature horses. STUDY DESIGN: Randomised experimental study. METHODS: Five horses were fasted overnight prior to receiving i.v. pimobendan (0.25 mg/kg bwt), intragastric (i.g.) pimobendan (0.25 mg/kg bwt) or i.g. placebo with a washout period of one week between each administration. Horses were instrumented for the measurement of right ventricular (RV) minimum pressure, RV maximum pressure, RV end diastolic pressure, and maximum rate of increase and decrease in RV pressure before and 0.5, 1, 2, 4, and 8 h after drug administration. Arterial blood pressure, central venous pressure, cardiac output and heart rate were measured at the same time points. Data were expressed as a maximum percentage of change over baseline values. RESULTS: There were no adverse effects associated with administration of pimobendan. The percentage increase in heart rate was significantly greater for horses given pimobendan i.g. (33 ± 4%) and i.v. (36 ± 14%) than for those given a placebo (-2 ± 7%). The percentage increase in maximum rate of increase in RV pressure (35 ± 36%) and the percentage decrease in minimum pressure (47 ± 24%) and end diastolic pressure (34 ± 13%) were significantly greater in horses given pimobendan i.v. than in those given placebo. Other variables measured were not significantly different between treatment groups. CONCLUSION: Pimobendan administered i.v. has positive chronotropic and inotropic effects in healthy mature horses and warrants further investigation for the treatment of heart failure in horses.

Effect of oral mineral and energy supplementation on blood mineral concentrations, energetic and inflammatory profile, and milk yield in dairy cows affected with dystocia.

The objectives of this study were to determine the effect of mineral/energy supplementation of dairy cows with dystocia on blood mineral concentrations, energetic and inflammatory profiles, and milk yield. Multiparous Holstein cows with dystocia were randomly assigned into two groups, (1) treated with a mineral/energy supplement (DME, n= 18) and (2) not treated (DNT, n= 22). A group of cows with normal parturition were randomly selected and were left untreated (NNT, n= 25). Cows in DME received an oral drench of 110 g of calcium and 400 g of propionate as calcium propionate plus 110 g potassium chloride and 150 g of magnesium sulfate administered within 6 h of calving and again 3 days post-partum. Compared to cows with a normal parturition, dystocic cows had decreased plasma calcium concentrations, increased plasma haptoglobin, decreased milk yield at 1 day post-partum, and tended to have increased rectal temperatures from 1 to 12 days post-partum. Compared with cows in DNT, those in DME had decreased plasma calcium concentrations and increased plasma magnesium concentrations 2 and 3 days post-partum, and a tendency for an increase in rectal temperature from 1 to 12 days post-partum. Dystocia is detrimental to calcium homeostasis post-partum, but mineral/energy supplementation as undertaken in this study is not recommended for use in cows with dystocia.

Pharmacodynamic evaluation of 4 angiotensin-converting enzyme inhibitors in healthy adult horses.

BACKGROUND: Angiotensin-converting enzyme (ACE) inhibitors are used in horses with cardiovascular disorders despite the paucity of available data regarding their efficacy. HYPOTHESIS: The degree of serum ACE inhibition varies considerably between drugs. ANIMALS: Eight healthy adult horses. METHODS: Randomized prospective study. Horses were fasted overnight prior to receiving one of 4 ACE inhibitors intragastrically, administered at one of 2 dosages, using a randomized Latin square design (benazepril: 0.5 and 0.25 mg/kg; ramipril: 0.3 and 0.1 mg/kg; quinapril: 0.25 and 0.125 mg/kg; perindopril: 0.1 and 0.05 mg/kg). Serum ACE activity was measured using a kinetic spectrophotometric method. RESULTS: There was a significant effect of drug and dosage on maximum ACE inhibition (I(max)), ACE inhibition 24 hours after administration (I(24h)), and area under the curve (AUC(0-48h)). Benazepril at 0.5 mg/kg resulted in significantly higher I(max) (86.9 ± 7.0%) and I(24h) (60.3 ± 7.9%) compared to the other drugs. There was a significant decrease in indirect blood pressure (BP) over time after administration of each drug, but differences in BP were not significantly different between drugs. Pharmacodynamic variables measured after administration of benazepril to horses with free access to hay were not significantly different from those obtained after fasting. Administration of benazepril orally once daily for 7 days did not result in a cumulative effect on ACE inhibition. CONCLUSIONS AND CLINICAL IMPORTANCE: Of the ACE inhibitors tested, oral benazepril (0.5 mg/kg) is the most effective at inhibiting serum ACE activity in healthy horses.

Conformational differences in the 3-D nanostructure of the immunoglobulin heavy-chain locus, a hotspot of chromosomal translocations in B lymphocytes.

Spectral precision distance microscopy was utilized to detect small but nonetheless consistently present conformational differences between the immunoglobulin heavy-chain gene clusters (IgH) that reside on the two chromosome 12 homologues in all diploid cells of the mouse. The euclidian distance (i.e., the mean arithmetic three-dimensional [3-D] distance) between the 5' most IgH gene, C mu, and the 3' most IgH gene, C alpha, was used as the indicator to define the co-presence of a condensed IgH domain and a relaxed IgH domain in the same cell. In normal and malignant B cells in which IgH is actively rearranged and transcribed, the C mu/C alpha distance (genomic distance approximately 180 kb) was found to range from 87.5 to 121 nm on the condensed IgH domain and from 154 to 207 nm on the relaxed IgH domain. In non-B cells (fibroblasts, neutrophils, and macrophages), in which IgH is inactive, the C mu/C alpha distance was found to range from 136 to 154 nm on the condensed IgH domain and from 250 to 292 nm on the related IgH domain. These results suggested that conformational differences that may predispose the relaxed IgH domain for illegitimate genetic recombinations, such as chromosomal translocations, are likely to exist in many cell types, including B cells. However, in B lymphocytes this structural predisposition may conspire with the lineage-specific ability to activate proto-oncogenes (after juxtaposition to IgH) to positively affect the preferential involvement of the relaxed IgH domain in chromosomal translocations. Additional studies are warranted to validate this working hypothesis.

Inducible mutagenesis in TEPC 2372, a mouse plasmacytoma cell line that harbors the transgenic shuttle vector lambdaLIZ.

The plasmacytoma cell line, TEPC 2372, was derived from a malignant plasma cell tumor that developed in the peritoneal cavity of a BALB/c mouse that harbored the transgenic shuttle vector for the assessment of mutagenesis in vivo, lambdaLIZ. TEPC 2372 was found to display the typical features of a BALB/c plasmacytoma. It consisted of pleomorphic plasma cells that secreted a monoclonal immunoglobulin (IgG2b/lambda), was initially dependent on the presence of IL-6 to grow in cell culture, contained a hyperdiploid chromosome complement with a tendency to undergo tetraploidization, and harbored a constitutively active c-myc gene by virtue of a T(6;15) chromosomal translocation. TEPC 2372 was further characterized by the ability to respond to in vitro exposure with 4-NQO (4-nitroquinoline-1-oxide), an oxidative model mutagen, with a vigorous dose-dependent increase in mutagenesis that peaked at a 7.85-fold elevation of mutant rates in lambdaLIZ when compared to background mutant rates in untreated controls. Cotreatment with 4-NQO and BSO (buthionine sulfoximine), a glutathione-depleting compound that causes endogenous oxidative stress, resulted in a 9.03-fold increase in the mutant frequency in lambdaLIZ. These results demonstrated that TEPC 2372, the malignant plasma cell counterpart of the lambdaLIZ-based in vivo mutagenesis assay, may be useful as an in vitro reference point for the further elucidation of oxidative mutagenesis in lymphoid tissues.

Translocation remodeling in the primary BALB/c plasmacytoma TEPC 3610.

Myc-activating chromosomal 12;15 translocations, the hallmark mutations of inflammation-induced BALB/c plasmacytomas, have recently been shown to undergo remodeling by isotype switch-like genetic recombinations that remove approximately 180 kb of immunoglobulin heavy-chain sequence in the vicinity of the rearranged, expressed Myc gene. Here we combine cytogenetic data on the 12;15 translocation (SKY and FISH) with the molecular analysis of key junction sites (long-range PCR followed by DNA sequencing) to demonstrate that translocation remodeling occurred as an infrequent, stepwise, and disomic tumor progression event in the tetraploid, fully transformed, and transplantable plasmacytoma TEPC 3610. This result was used, in conjunction with previously obtained molecular data on five other primary plasmacytomas, to devise a hypothesis that predicts that the selective pressure to undergo translocation remodeling may be predetermined by the location of the break site in Myc. The pressure may be low if the break occurs 5' of the normal promoter region of Myc, but it may be considerably stronger if the break occurs 3' of the Myc promoter. Published 2001 Wiley-Liss, Inc.

Chromosomes 1 and 5 harbor plasmacytoma progressor genes in mice.

Mouse spectral karyotyping (SKY) was employed to analyze 29 primary BALB/c plasmacytomas (PCTs) for the presence of chromosomal aberrations that took place subsequent to the Myc-activating T(12F1;15D2) or T(6C1;15D2) translocations, the initiating oncogenic mutations in plasmacytomagenesis. Recurrent amplifications of chromosome (Chr) 1 (48% prevalence) and promiscuous non-reciprocal translocations of Chr 5 (52% prevalence) suggested the existence of important PCT progressor genes on bands 1B/C and 5F. The additional occurrence of sporadic aberrations (93% prevalence) most likely reflected the general instability of the PCT genome. This instability, however, was not consistent, as two PCTs lacked secondary cytogenetic changes detectable by SKY. Our findings led us to conclude that BALB/c PCTs show a remarkably similar degree of cytogenetic heterogeneity to human multiple myeloma, despite being genetically defined (inbred mouse strain) and uniformly initiated (deregulation of Myc). Published 2000 Wiley-Liss, Inc.

A bromodomain protein, MCAP, associates with mitotic chromosomes and affects G(2)-to-M transition.

We describe a novel nuclear factor called mitotic chromosome-associated protein (MCAP), which belongs to the poorly understood BET subgroup of the bromodomain superfamily. Expression of the 200-kDa MCAP was linked to cell division, as it was induced by growth stimulation and repressed by growth inhibition. The most notable feature of MCAP was its association with chromosomes during mitosis, observed at a time when the majority of nuclear regulatory factors were released into the cytoplasm, coinciding with global cessation of transcription. Indicative of its predominant interaction with euchromatin, MCAP localized on mitotic chromosomes with exquisite specificity: (i) MCAP-chromosome association became evident subsequent to the initiation of histone H3 phosphorylation and early chromosomal condensation; and (ii) MCAP was absent from centromeres, the sites of heterochromatin. Supporting a role for MCAP in G(2)/M transition, microinjection of anti-MCAP antibody into HeLa cell nuclei completely inhibited the entry into mitosis, without abrogating the ongoing DNA replication. These results suggest that MCAP plays a role in a process governing chromosomal dynamics during mitosis.

Genomic organisation and expression of BCL6 in murine B-cell lymphomas.

BCL6 encodes a transcription factor deregulated by chromosomal translocations in human diffuse large cell B lymphomas (DLCL). This study was designed to determine whether Bcl6 might also be involved in lymphomas of mice. BCL6 protein was expressed at high levels in 90% or more of DLCL but not in low grade B lymphomas. Southern hybridisation studies demonstrated altered organisation of Bcl6 in three primary DLCL and the WEHI 231 B-cell lymphoma cell line but not in low grade tumours. Chromosomal painting and fluorescence in situ hybridisation (FISH) analyses of the WEHI 231 metaphase spreads revealed a T(5;16) translocation with Bcl6 on Chromosome 16 at the translocation breakpoint. Deregulated expression of BCL6 is thus likely to contribute to the genesis of DLCL of mice as well as of humans.

Transient epileptic amnesia in dementia: a treatable unrecognized cause of episodic amnestic wandering.

The authors present two patients with dementia who displayed recurrent transient episodes of amnestic wandering and disorientation characterized by getting lost in familiar environments. At other times these patients did not wander or become disoriented. The inability to recall any information during these episodes, and the marked difference of the episodic amnesia exacerbations from the progressive amnesia characteristic of Alzheimer disease seen in these patients led to their evaluation. These clinical episodes and the bilateral interictal epileptiform electroencephalographic changes found in both patients led to the diagnosis of transient epileptic amnesia, a syndrome that can be diagnostically elusive. These transient amnestic wandering events subsided after treatment with antiepileptic drugs in both patients. The authors suggest that transient wandering of this type may be caused by ictal events or postictal confusional states. This report emphasizes the importance of recognizing transient epileptic amnesia as an easily treatable cause of episodic behavioral abnormalities responsive to antiepileptic therapy, especially in those patients who have a markedly inconsistent pattern of wandering, disorientation in familiar settings, and amnesia exacerbation manifested by no recall of the emotional stress of getting lost or of any information during these episodes. Recognition of this type of behavioral disruption and its proper treatment can lead to improved quality of life for these patients, maintain these patients in their homes and out of chronic care institutions longer, and facilitate the community's and caretaker's interactive roles with the patient.

Cytogenetic analysis of the bipotential murine pre-B cell lymphoma, P388, and its derivative macrophage-like tumor, P388D1, using SKY and CGH.

Spectral karyotyping (SKY) and comparative genomic hybridization (CGH) were used to elucidate the divergent cytogenetic make-up of the prototypical bilineage lymphoblastic pre-B lymphoma, P388, and its progenitor macrophage-like tumor, P388D1. P388 was found to be diploid and genomically stable. P388D1 was triploid, highly unstable and characterized by numerous marker chromosomes (Chrs) and composite rearrangements. The karyotype of P388D1 was so complex that its clonal relatedness to P388 would have remained questionable without confirmation by molecular analysis of the clonotypic immunoglobulin heavy-chain and light-chain gene recombinations that coexisted in both tumors. The intrinsic instability of the P388D1 genome was indicated by the observation that only four out of 42 aberrations uncovered by SKY (in a total of 27 metaphases) occurred consistently (100% incidence), whereas 27 changes occurred non-randomly (27 to 96% incidence) and 11 alterations randomly (4 to 11% incidence). Persistent cytogenetic instability was also observed in P388 'macrophages' after phorbol ester- and ionomycin-induced conversion in vitro of P388 lymphoma cells. The 'cytogenetic noise' in these cells was manifested by a multiplicity of sporadic chromosomal aberrations; ie 25 distinct changes were identified by SKY in 40 metaphases. The results in P388D1 and P388 'macrophages' were interpreted to indicate that the myeloid differentiation program in the bipotential pre-B cell lymphoma P388 is invariably characterized by karyotypic instability. The study presented here demonstrates the power of the combined SKY and CGH approach to resolve complicated karyotypes of important and widely used mouse tumors.