Measurements of neutrino oscillation parameters from the T2K experiment using 3.6×1021 protons on target

The T2K experiment presents new measurements of neutrino oscillation parameters using 19.7 ( 16.3 ) × 10 20 protons on target (POT) in (anti-)neutrino mode at the far detector (FD). Compared to the previous analysis, an additional 4.7 × 10 20 POT neutrino data was collected at the FD. Significant improvements were made to the analysis methodology, with the near-detector analysis introducing new selections and using more than double the data. Additionally, this is the first T2K oscillation analysis to use NA61/SHINE data on a replica of the T2K target to tune the neutrino flux model, and the neutrino interaction model was improved to include new nuclear effects and calculations. Frequentist and Bayesian analyses are presented, including results on sin 2 θ 13 and the impact of priors on the δ CP measurement. Both analyses prefer the normal mass ordering and upper octant of sin 2 θ 23 with a nearly maximally CP-violating phase. Assuming the normal ordering and using the constraint on sin 2 θ 13 from reactors, sin 2 θ 23 = 0 . 561 - 0.032 + 0.021 using Feldman-Cousins corrected intervals, and Δ m 32 2 = 2 . 494 - 0.058 + 0.041 × 10 - 3 eV 2 using constant Δ χ 2 intervals. The CP-violating phase is constrained to δ CP = - 1 . 97 - 0.70 + 0.97 using Feldman-Cousins corrected intervals, and δ CP = 0 , π is excluded at more than 90% confidence level. A Jarlskog invariant of zero is excluded at more than 2 σ credible level using a flat prior in δ CP , and just below 2 σ using a flat prior in sin δ CP . When the external constraint on sin 2 θ 13 is removed, sin 2 θ 13 = 28 . 0 - 6.5 + 2.8 × 10 - 3 , in agreement with measurements from reactor experiments. These results are consistent with previous T2K analyses.

Search for Electron Antineutrino Appearance in a Long-Baseline Muon Antineutrino Beam

Electron antineutrino appearance is measured by the T2K experiment in an accelerator-produced antineutrino beam, using additional neutrino beam operation to constrain parameters of the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix. T2K observes 15 candidate electron antineutrino events with a background expectation of 9.3 events. Including information from the kinematic distribution of observed events, the hypothesis of no electron antineutrino appearance is disfavored with a significance of 2.40σ and no discrepancy between data and PMNS predictions is found. A complementary analysis that introduces an additional free parameter which allows non-PMNS values of electron neutrino and antineutrino appearance also finds no discrepancy between data and PMNS predictions.

Nanostrain sensitivity in a wire torsion experiment

The feasibility of a thin-wire torsion stress-strain experiment with nanostrain sensitivity is demonstrated. A gauge length of 50 m was made possible by using The Monument, London, thereby restoring it to its original purpose as a scientific instrument. A wire of 150 μm diameter was studied using the load-unload method, and data were recorded in the elastic regime and through the elastic-plastic transition. Analysis of this preliminary experiment suggested some necessary improvements to the equipment and methods. Progress towards definitive experiments is described together with difficulties still to be overcome.

Search for CP Violation in Neutrino and Antineutrino Oscillations by the T2K Experiment with 2.2×10^{21} Protons on Target

The T2K experiment measures muon neutrino disappearance and electron neutrino appearance in accelerator-produced neutrino and antineutrino beams. With an exposure of 14.7(7.6)×10^{20} protons on target in the neutrino (antineutrino) mode, 89 ν_{e} candidates and seven anti-ν_{e} candidates are observed, while 67.5 and 9.0 are expected for δ_{CP}=0 and normal mass ordering. The obtained 2σ confidence interval for the CP-violating phase, δ_{CP}, does not include the CP-conserving cases (δ_{CP}=0, π). The best-fit values of other parameters are sin^{2}θ_{23}=0.526_{-0.036}^{+0.032} and Δm_{32}^{2}=2.463_{-0.070}^{+0.071}×10^{-3}  eV^{2}/c^{4}.

Combined Analysis of Neutrino and Antineutrino Oscillations at T2K

T2K reports its first results in the search for CP violation in neutrino oscillations using appearance and disappearance channels for neutrino- and antineutrino-mode beams. The data include all runs from January 2010 to May 2016 and comprise 7.482×10^{20} protons on target in neutrino mode, which yielded in the far detector 32 e-like and 135  μ-like events, and 7.471×10^{20} protons on target in antineutrino mode, which yielded 4 e-like and 66  μ-like events. Reactor measurements of sin^{2}2θ_{13} have been used as an additional constraint. The one-dimensional confidence interval at 90% for the phase δ_{CP} spans the range (-3.13, -0.39) for normal mass ordering. The CP conservation hypothesis (δ_{CP}=0, π) is excluded at 90% C.L.

Measurement of Coherent π^{+} Production in Low Energy Neutrino-Carbon Scattering

We report the first measurement of the flux-averaged cross section for charged current coherent π^{+} production on carbon for neutrino energies less than 1.5 GeV, and with a restriction on the final state phase space volume in the T2K near detector, ND280. Comparisons are made with predictions from the Rein-Sehgal coherent production model and the model by Alvarez-Ruso et al., the latter representing the first implementation of an instance of the new class of microscopic coherent models in a neutrino interaction Monte Carlo event generator. We observe a clear event excess above background, disagreeing with the null results reported by K2K and SciBooNE in a similar neutrino energy region. The measured flux-averaged cross sections are below those predicted by both the Rein-Sehgal and Alvarez-Ruso et al.

Measurement of Muon Antineutrino Oscillations with an Accelerator-Produced Off-Axis Beam

T2K reports its first measurements of the parameters governing the disappearance of ν[over ¯]_{μ} in an off-axis beam due to flavor change induced by neutrino oscillations. The quasimonochromatic ν[over ¯]_{μ} beam, produced with a peak energy of 0.6 GeV at J-PARC, is observed at the far detector Super-Kamiokande, 295 km away, where the ν[over ¯]_{μ} survival probability is expected to be minimal. Using a data set corresponding to 4.01×10^{20} protons on target, 34 fully contained μ-like events were observed. The best-fit oscillation parameters are sin^{2}(θ[over ¯]_{23})=0.45 and |Δm[over ¯]_{32}^{2}|=2.51×10^{-3}  eV^{2} with 68% confidence intervals of 0.38-0.64 and 2.26-2.80×10^{-3}  eV^{2}, respectively. These results are in agreement with existing antineutrino parameter measurements and also with the ν_{μ} disappearance parameters measured by T2K.

Measurement of the inclusive electron neutrino charged current cross section on carbon with the T2K near detector

The T2K off-axis near detector ND280 is used to make the first differential cross-section measurements of electron neutrino charged current interactions at energies ∼1  GeV as a function of electron momentum, electron scattering angle, and four-momentum transfer of the interaction. The total flux-averaged ν(e) charged current cross section on carbon is measured to be ⟨σ⟩(ϕ)=1.11±0.10(stat)±0.18(syst)×10⁻³⁸ cm²/nucleon. The differential and total cross-section measurements agree with the predictions of two leading neutrino interaction generators, NEUT and GENIE. The NEUT prediction is 1.23×10⁻³⁸ cm²/nucleon and the GENIE prediction is 1.08×10⁻³⁸ cm²/nucleon. The total ν(e) charged current cross-section result is also in agreement with data from the Gargamelle experiment.

Precise measurement of the neutrino mixing parameter θ23 from muon neutrino disappearance in an off-axis beam

New data from the T2K neutrino oscillation experiment produce the most precise measurement of the neutrino mixing parameter θ23. Using an off-axis neutrino beam with a peak energy of 0.6 GeV and a data set corresponding to 6.57×10(20) protons on target, T2K has fit the energy-dependent νμ oscillation probability to determine oscillation parameters. The 68% confidence limit on sin(2)(θ23) is 0.514(-0.056)(+0.055) (0.511±0.055), assuming normal (inverted) mass hierarchy. The best-fit mass-squared splitting for normal hierarchy is Δm32(2)=(2.51±0.10)×10(-3)  eV(2)/c(4) (inverted hierarchy: Δm13(2)=(2.48±0.10)×10(-3)  eV(2)/c(4)). Adding a model of multinucleon interactions that affect neutrino energy reconstruction is found to produce only small biases in neutrino oscillation parameter extraction at current levels of statistical uncertainty.

Observation of electron neutrino appearance in a muon neutrino beam

The T2K experiment has observed electron neutrino appearance in a muon neutrino beam produced 295 km from the Super-Kamiokande detector with a peak energy of 0.6 GeV. A total of 28 electron neutrino events were detected with an energy distribution consistent with an appearance signal, corresponding to a significance of 7.3σ when compared to 4.92±0.55 expected background events. In the Pontecorvo-Maki-Nakagawa-Sakata mixing model, the electron neutrino appearance signal depends on several parameters including three mixing angles θ12, θ23, θ13, a mass difference Δm(32)(2) and a CP violating phase δ(CP). In this neutrino oscillation scenario, assuming |Δm(32)(2)|=2.4×10(-3)  eV(2), sin(2)θ(23)=0.5, and Δm322>0 (Δm(32)(2)<0), a best-fit value of sin(2)2θ(13)=0.140(-0.032)(+0.038) (0.170(-0.037)(+0.045)) is obtained at δ(CP)=0. When combining the result with the current best knowledge of oscillation parameters including the world average value of θ(13) from reactor experiments, some values of δ(CP) are disfavored at the 90% C.L.

Measurement of neutrino oscillation parameters from muon neutrino disappearance with an off-axis beam

The T2K Collaboration reports a precision measurement of muon neutrino disappearance with an off-axis neutrino beam with a peak energy of 0.6 GeV. Near detector measurements are used to constrain the neutrino flux and cross section parameters. The Super-Kamiokande far detector, which is 295 km downstream of the neutrino production target, collected data corresponding to 3.01×10(20) protons on target. In the absence of neutrino oscillations, 205±17 (syst) events are expected to be detected while only 58 muon neutrino event candidates are observed. A fit to the neutrino rate and energy spectrum, assuming three neutrino flavors and normal mass hierarchy yields a best-fit mixing angle sin2(θ23)=0.514±0.082 and mass splitting |Δm(32)(2)|=2.44(-0.15)(+0.17)×10(-3) eV2/c4. Our result corresponds to the maximal oscillation disappearance probability.

Indication of electron neutrino appearance from an accelerator-produced off-axis muon neutrino beam

The T2K experiment observes indications of ν(μ) → ν(e) appearance in data accumulated with 1.43×10(20) protons on target. Six events pass all selection criteria at the far detector. In a three-flavor neutrino oscillation scenario with |Δm(23)(2)| = 2.4×10(-3)  eV(2), sin(2)2θ(23) = 1 and sin(2)2θ(13) = 0, the expected number of such events is 1.5±0.3(syst). Under this hypothesis, the probability to observe six or more candidate events is 7×10(-3), equivalent to 2.5σ significance. At 90% C.L., the data are consistent with 0.03(0.04) < sin(2)2θ(13) < 0.28(0.34) for δ(CP) = 0 and a normal (inverted) hierarchy.

A conical slit for three-dimensional XRD mapping

Traditionally, depth resolution in diffraction experiments is obtained by inserting pinholes in both the incoming and diffracted beam. For materials science investigations of local strain and texture properties this leads to very slow data-acquisition rates, especially when characterization is performed on the level of the individual grains. To circumvent this problem a conical slit has been manufactured by wire-electrodischarge machining. The conical slit has six 25 microm-thick conically shaped openings matching six of the Debye-Scherrer cones from a face-centred-cubic powder. By combining the slit with a microfocused incoming beam of hard X-rays, an embedded gauge volume is defined. Using a two-dimensional detector, fast and complete information can be obtained regarding the texture and strain properties of the material within this particular gauge volume. The average machining and assemblage errors of the conical slit are found both to be of the order of 5 microm. An algorithm for alignment of the slit is established, and the potential of the technique is illustrated with an example of grain mapping in a 4.5 mm-thick Cu sample.

Horner's syndrome: a rare presentation of cervical sympathetic chain schwannoma

We describe a cervical sympathetic chain schwannoma in a 77-year-old woman who presented with a neck mass and Horner's syndrome. Such schwannomas are rare and this is the first documented case of a Horner's syndrome at presentation. The mass was excised via a cervical approach and her post-operative course was uneventful. The prognosis is excellent, with recurrence being rare. A brief discussion of the pathology, presentation, diagnosis, and treatment of this condition is made in this paper. The relevance of the uncertainty in diagnosis is discussed with the message that a pre-operative Horner's syndrome may guide the surgeon in the care of the patient but we suggest that in all cases proper counselling of the possible neurological consequences of this surgery be conducted.

L-Arginine, nitric oxide, and intestinal secretion: studies in rat jejunum in vivo

BACKGROUND

L-Arginine has been shown to induce fluid secretion in human jejunum. Nitric oxide, a derivative of L-arginine is thought to have an important role as an intestinal secretagogue.

AIM

To determine the effect of L-arginine and the nitric oxide synthase inhibitor, nitro L-arginine methyl ester (L-NAME), on fluid and electrolyte movement in rat jejunum.

METHODS

A 25 cm segment of rat jejunum was perfused in situ with iso-osmotic solutions containing either (1) saline, (2) D-arginine 20, (3) L-arginine 20, (4) L-NAME 0.1, 1, or 20 mmol/l, or (5) a combination of L-arginine 20 and L-NAME 0.1, 1, or 20 mmol/l. In further groups the effect of a subcutaneous injection of L-NAME 100 mg/kg was examined in rats pretreated with either D-or L-arginine 500 mg/kg.

RESULTS

L-Arginine, unlike D-arginine, induced fluid secretion despite being better absorbed (mean -7.3 v 17.0 microliters/min/g; p < 0.01). L-NAME at 0.1 mmol/l had no effect on basal fluid movement but reversed L-arginine induced secretion (7.8; p < 0.05). L-NAME at 1 and 20 mmol/l induced fluid secretion (-15.4 and -28.4, respectively), which was enhanced by the addition of L-arginine (-30.0 and -41.0, respectively; both p < 0.05). A subcutaneous injection of L-NAME resulted in marked fluid secretion (-39.9) and histological evidence of intestinal ischaemia. These changes were attenuated or reversed by pretreatment with subcutaneous L- but not D-arginine.

CONCLUSIONS

L-arginine induces intestinal fluid secretion through production of nitric oxide. There is a delicate balance between the effect of nitric oxide as a secretagogue and its effect on maintaining blood flow and thus preventing intestinal ischaemia.

The morphology of juxtaglomerular cell hyperplasia and hypertrophy in normotensive rats and monkeys given an angiotensin II receptor antagonist

L-694,492 (DUP 532), an angiotensin II (AII) receptor antagonist, was given orally at 125 mg/kg/day to rats and monkeys for up to 6 mo to assess the effects of the compound on juxtaglomerular (JG) cells. In rats, mild JG cell hypertrophy/hyperplasia occurred and was associated with a 12-fold increase in the bromodeoxyuridine-labeling index of JG cells and a 10-fold increase in renal renin content. Ultrastructurally, intermediate cells with characteristics of both smooth muscle cells and granulated renin-producing cells as well as hypertrophied renin-synthesizing cells were seen in the afferent arterioles. In monkeys, marked hypertrophy and hyperplasia were seen with an 80% increase in JG cell numbers, mitotic activity, and a greatly increased renin content compared to controls. Three mo after drug withdrawal, an increased number of cells remained, which showed features of smooth muscle cells with essentially no renin. These results show that AII receptor antagonism stimulates increased renal renin production by hypertrophy of existing granulated cells, metaplasia of smooth muscle cells to renin-synthesizing cells, and cell proliferation. When treatment was discontinued, the renin-producing cells redeveloped the features of smooth muscle, but, as we have shown with enalapril (angiotensin-converting enzyme inhibitor), the increase in their number persists for at least 3 mo.

The morphology of juxtaglomerular cell hyperplasia and hypertrophy in normotensive rats and monkeys given an angiotensin II receptor antagonist

L-694,492 (DUP 532), an angiotensin II (AII) receptor antagonist, was given orally at 125 mg/kh/day to rats and monkeys for up to 6 mo to assess the effects of the compound on juxtaglomerular (JG) cells. In rats, mild JG cell hypertrophy/hyperplasia occurred and was associated with a 12-fold increase in the bromodeoxyuridine-labeling index of JG cells and a 10-fold increase in renal renin content. Ultrastructurally, intermediate cells with characteristics of both smooth muscle cells and granulated renin-producing cells as well as hypertrophied renin-synthesizing cells were seen in the afferent arterioles. In monkeys, marked hypertrophy and hyperplasia were seen with an 80% increase in JG cell numbers, mitotic activity, and a greatly increased renin content compared to controls. Three mo after drug withdrawal, an increased number of cells remained, which showed features of smooth muscle cells with essentially no renin. These results show that AII receptor antagonism stimulates increased renal renin production by hypertrophy of existing granulated cells, metaplasia of smooth muscle cells to renin-synthesizing cells, and cell proliferation. When treatment was discontinued, the renin-producing cells redeveloped the features of smooth muscle cells, but, as we have shown with enalapril (augioteusin-converting enzyme inhibitor), the increase in their number persists for at least 3 mo.

Juxtaglomerular cell hypertrophy and hyperplasia induced in rhesus monkeys by angiotensin II receptor antagonists

BACKGROUND

Juxtaglomerular (JG) cell hypertrophy and hyperplasia were investigated in rhesus monkeys given angiotensin II (AII) AT1 receptor antagonists L-158,338 and DUP 753 (MK-0954, losartan).

EXPERIMENTAL DESIGN

In 2 initial studies, L-158,338 was given orally at 10, 30, and 90 mg/kg/day for 3 or 14 weeks. To investigate the observed JG hypertrophy and hyperplasia, in a third 5-week experiment L-158,338 was given alone at 90 mg/kg/day, or with physiologic saline supplementation at 25 ml/kg/day, or coadministered with the angiotensin converting enzyme inhibitor enalapril at 10 mg/kg/day. Physiologic saline was given to attempt to suppress renin release through volume expansion and/or sodium retention. Enalapril was given to lower plasma AII levels and observe whether JG cell hypertrophy and hyperplasia were increased or decreased. For comparison, DUP 753 was given at 90 and 300 mg/kg/day. Plasma renin activity and AII concentration were measured in this study.

RESULTS

Dose- and time-dependent increases in JG cell hypertrophy and hyperplasia were seen in the 2 initial experiment. In the third experiment, plasma renin activity and AII concentration were increased 3-fold and 6-fold over pretest values by L-158,338 at 90 mg/kg/day for 5 weeks. Saline supplementation had no effect on these parameters but diminished the group mean severity grade for JG hypertrophy and hyperplasia from 1.5 to 1.0. Enalapril coadministration had no effect on plasma renin activity, whereas it blunted the plasma AII increase caused by L-158,338 and increased the group mean grade to 2.5. DUP 753 at 300 mg/kg/day produced similar increases in plasma renin activity and AII concentration but only resulted in grade 1 JG cell hypertrophy and hyperplasia.

CONCLUSIONS

L-158,338-induced JG cell hypertrophy and hyperplasia is an exaggerated pharmacologic response that can be modulated by saline supplementation and angiotensin converting enzyme inhibition. These results suggest that decreased renal perfusion or altered sodium homeostasis and plasma AII concentration are important variables that contribute to AT1 receptor blockade to induce JG cell hypertrophy and hyperplasia.

Acid secretion from a Meckel's diverticulum: the unsuspected mimic of Crohn's disease?

The commonest causes of ulceration in the terminal ileum are Crohn's disease, infection, and neoplasia. Meckel's diverticulum is said to be found more commonly in patients with Crohn's disease than in the general population. We describe a patient who developed extensive terminal ileal ulceration caused by acid secretion from gastric mucosa within a Meckel's diverticulum, a condition that has not been recognized before. Our patient demonstrated a number of clinical features that would be consistent with Crohn's disease, and we wonder whether the rare condition of "Meckel's ileitis" is occasionally misdiagnosed as Crohn's disease in other patients.

Association between Meckel's diverticulum and Crohn's disease: a retrospective review

The operation notes and pathology records of 294 consecutive patients who had right hemicolectomy for Crohn's disease were reviewed. A Meckel's diverticulum was found in 17 (5.8%) of these patients, 2-3 times the expected rate in the general population. At least 50% of diverticula in the normal population contain heterotopic mucosa, but none was found in those diverticula that were examined from this group. The increased prevalence of Meckel's diverticulum in patients with Crohn's disease confirms previous anecdotal reports, but the cause for the increased frequency remains unexplained. The significance of this finding is discussed.

Renal papillary cytoplasmic granularity and potassium depletion induced by carbonic anhydrase inhibitors in rats

Renal papillary cytoplasmic granularity (RPCG) induced by carbonic anhydrase inhibitors (CAIs) in rats is characterized by the accumulation of dense secondary lysosomes in epithelial, endothelial, and interstitial cells and may be related to drug-induced potassium depletion. Female Sprague-Dawley rats were given the CAI, acetazolamide, by gavage. Half were supplemented with 1% potassium chloride in the drinking water. Two treated groups were allowed to recover for 1 or 2 mo. Potassium supplementation inhibited RPCG by 80% but produced little amelioration of the mild 13% decrease in serum potassium induced by 200 mg/kg/day acetazolamide for 28 days. Acetazolamide-induced RPCG is reversible because 1- and 2-mo recovery periods decreased the incidence by 75% and 80%, respectively. The results support the hypothesis that RPCG is related to potassium depletion secondary to carbonic anhydrase inhibition. Because supplementation of potassium chloride had little effect on serum potassium, these data suggest that depletion of renal medullary potassium content is important in the pathogenesis of RPCG as previously suggested by others. Other types of diuretics that produce hypokalemia as a side effect may not deplete medullary potassium since RPCG has not been reported in humans or animals given these drugs.

Primary lymphoma of the small intestine. A clinicopathological study of 119 cases

Small bowel lymphomas account for 20 to 40% of primary gut lymphomas in Western populations and are among the most common malignant tumours of the small bowel. We studied 119 cases of primary small bowel lymphoma presenting over 4 decades. Two thirds of the patients were men with a peak age incidence in the 7th decade. Common presenting features included abdominal pain, weight loss, small bowel obstruction, and acute abdomen. Tumours were classified using the Kiel European Association for Haematopathology Geneva Workshop scheme and phenotyped on paraffin sections; 66% were B cells, and 34% were T cell. In all cases, the antibodies L26 and polyclonal CD3 reliably distinguished between B- and T-cell tumours. Of the B-cell lymphomas, 62% were diffuse high grade, 20% were low-grade lymphomas of mucosa-associated lymphoid tissue, 11% had both low- and high-grade components, and 7% were other low-grade types. Of the T-cell lymphomas, 83% were high grade, and 49% were enteropathy associated. Most T-cell lymphomas were ulcerated plaques or strictures in the proximal small bowel; B-cell lymphomas tended to be annular or polypoid masses in the distal and terminal ileum. Survival data showed that low-grade B-cell lymphomas had the best outcome and T-cell lymphomas the worst. Adverse prognostic features included perforation, high-grade histology, multiple tumours and advanced stage.

High frequency of K-ras mutations in sporadic colorectal adenomas

The frequency of activating mutations at codons 12 and 13 of the K-ras gene was investigated in 57 sporadic adenomas from 47 patients using the polymerase chain reaction and oligonucleotide hybridisation assay. Sixty eight per cent of the adenomas tested were positive for K-ras mutations. This high frequency, combined with the lack of a correlation between mutations and adenoma size, suggest that K-ras mutations occur earlier in the adenoma-carcinoma sequence than has previously been suggested. The high frequency observed in sporadic adenomas contrasts with the reported low frequency (18%) in adenomas from patients with familial adenomatous polyposis (FAP), suggesting a possible difference in the molecular genesis of FAP and non-FAP adenomas. Finally, it was found that adenomas from patients with a personal history of colorectal cancer were more likely to contain a K-ras mutation than those from patients with no such history. This is a new finding and worthy of further study.

Successful treatment of a primary endodermal sinus tumor of the liver

A 27-year-old woman had a large hepatic tumor and a markedly increased serum alpha-fetoprotein (AFP) level. A diagnosis of endodermal sinus tumor was made after a needle biopsy was performed on the liver. Clinical and radiologic examinations did not show an alternative primary site. Treatment with cisplatin, etoposide, and bleomycin was started, but, after three cycles, was changed to cisplatin, vincristine, methotrexate, bleomycin, dactinomycin, cyclophosphamide, and etoposide because the serum AFP level was decreasing too slowly. After additional chemotherapy was given, the patient was well but had an increased AFP level and a large residual mass in the liver. A right hemihepatectomy was performed, but no viable tumor was present. The patient is alive and disease-free 5 years later. Thus, AFP levels may be misleading in the presence of large necrotic tumors. The authors stress the need to make a diagnosis of these rare tumors early because aggressive treatment with combination chemotherapy may result in cure.

Rat urinary bladder hyperplasia induced by oral administration of carbonic anhydrase inhibitors

The carbonic anhydrase inhibitors, acetazolamide and MK-0927, were given by oral route to male Sprague-Dawley rats at 200 mg/kg/day and 25 mg/kg/day, respectively, for up to 4 weeks. Sequential necropsies were performed and urinary bladders were examined by light microscopy (LM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Similar urinary bladder changes were seen with both compounds. SEM evidenced slight multifocal urothelial changes consisting of cell swelling, dissociation, degeneration, and exfoliation after 3 and 5 days of treatment. After 2 and 4 weeks of treatment, elevated or leafy microridges on the luminal cell surfaces were seen together with foci of swollen cells. After a 2-month-recovery-period, the urothelial surfaces were normal. LM and TEM showed multifocal vacuolation of the urothelium associated with inflammation of the underlying lamina propria after 3 and 5 days of treatment. Cellular hypertrophy and hyperplasia of the transitional epithelium was seen after a 5-day treatment, persisted without increasing severity after 2 and 4 weeks of treatment, and totally regressed after the recovery period. It was concluded that, in the rat urinary bladder, oral administration of acetazolamide and MK-0927 induced early degeneration and inflammation followed by epithelial regeneration, resulting in a reversible hyperplasia of the transitional epithelium.

Urothelial hyperplasia induced by carbonic anhydrase inhibitors (CAIs) in animals and its relationship to urinary Na and pH

Investigations of MK-0927 and acetazolamide, both carbonic anhydrase inhibitors (CAIs), showed that urothelial hyperplasia develops in rats and mice, but not in rabbits, dogs, or monkeys. Rats given MK-0927 orally had a rapid onset of the change which regresses often completely despite continued treatment. Increased urinary pH and Na excretion, pharmacologic effects of CAIs, tended to be correlated with lesions. Rats given MK-0927 orally and fed either a 5% potassium phosphate meal or a 5% ammonium chloride meal had reduced urinary pH and/or urinary Na excretion and a reduced incidence of urothelial hyperplasia. Rats given MK-0927 orally and fed a low Na diet had very low urinary Na and essentially no urothelial hyperplasia. It was concluded that a clear relation exists between increased urinary Na excretion and pH, and urothelial hyperplasia induced by CAIs. These results in rats confirm the importance of increased Na and pH as stimuli for the development of urothelial hyperplasia.

An intragenic region downstream from the dihydrofolate reductase promoter is required for replication-dependent expression

The gene encoding dihydrofolate reductase (DHFR) is down-regulated as myoblasts withdraw from the cell cycle and commit to terminal differentiation. To localize cis-acting elements involved in regulating DHFR gene expression, the DHFR promoter and upstream region, together with differing amounts of contiguous intragenic sequence, were fused to the bacterial chloramphenicol acetyltransferase (CAT) gene. The resulting fusion genes were stably transformed into muscle cells, and CAT mRNA levels were measured in proliferative myoblasts and committed myocytes. A gene consisting of the -850/+465 region of DHFR (numbers refer to distance in base pairs from transcription initiation site) fused to CAT was efficiently expressed in proliferating myoblasts and was appropriately down-regulated during commitment. A gene consisting of the -850/+60 region of DHFR fused to CAT was poorly expressed in proliferating myoblasts and was not down-regulated during commitment. When inserted between the Rous sarcoma virus promoter and CAT sequence of RSVpCAT, the +61/+465 region of the DHFR gene augmented CAT mRNA expression in muscle cell transformants but did not confer a regulated pattern of expression. Our data indicate that DHFR sequences between +60 and +465 are required but are not sufficient for replication-dependent expression. The DHFR sequences may be operating at either a transcriptional or posttranscriptional level.

Caecal intussusceptions in horses and the significance of Anoplocephala perfoliata

A caecocaecal intussusception in a pony and a caecocolic intussusception in a horse, both infected with Anoplocephala perfoliata, are described and the relevance of tapeworms in such intestinal disease of horses is reviewed.

The varied appearances of starch particles in smears and paraffin sections

Evidence is presented to show that maize starch particles, usually recognized in histological sections by their Maltese cross birefringence under cross-polarized light, lose this characteristic appearance when transected by the microtome blade. Such particles are, therefore, likely to be overlooked. Though maize starch usually enters the abdomen during surgery, the female genital tract is another possible route from sources such as contraceptive devices. Other types of starch particle have different shapes, sizes and surface markings and these may be distinguished from maize starch by light and electron optical methods.

Prevalence of Anoplocephala perfoliata in horses and ponies in Clwyd, Powys and adjacent English marches

The prevalence of Anoplocephala perfoliata in 103 horses and ponies from Clwyd, Powys and the adjacent English marches, slaughtered during January 1987, was 69 per cent.

Transglutaminase-catalysed cross-linking of proteins phosphorylated in the intact glucose-stimulated pancreatic beta-cell

Incubation of intact islets in the presence of [32P]Pi and stimulatory levels of glucose followed by separation of phosphorylated islet proteins by SDS-polyacrylamide gel electrophoresis revealed the presence of a high molecular weight phosphopolymer which did not transverse a 3% (w/v) acrylamide gel. The majority of this phosphopolymer (approx. 70%) was present in the 600 x g sedimented fraction of islet homogenates. Islet homogenates obtained from intact islets previously incubated with [32P]Pi and stimulatory levels of glucose when incubated under conditions that activated the islet transglutaminase resulted in an increase in the amount of phosphopolymer present in the 600 x g sedimented fraction. Inhibitors of transglutaminase activity which are known to inhibit glucose-stimulated insulin release led to a significant reduction in the fraction of phosphopolymer present in the glucose-stimulated intact islet. These findings suggest that protein cross-linking and phosphorylation reactions may be closely linked in the pancreatic beta-cell.

Two cases of equine primary gastric impaction

The clinical details of two cases of equine primary gastric impaction are described and the syndromes of gastric impaction and dilatation are discussed. Both cases of gastric impaction were successfully treated by gastrotomy and evacuation of the gastric contents.

Clinical observations on the use of BCG cell wall fraction for treatment of periocular and other equine sarcoids

Clinical observations on the use of BCG cell wall fraction in oil for treating seven horses with periocular sarcoids and five horses with sarcoids in other regions are described. Therapy was successful when used for periocular or solitary and smaller sarcoids. For sarcoids previously treated with cryosurgery, therapy appeared to be less efficient. A horse with a sarcoid on the stifle developed a septic gonitis due to necrosis of the sarcoid tissue adjacent to the joint. Sarcoids of the axilla appeared to be more aggressive than sarcoids at other locations and did not respond favourably to this form of therapy.

Leiomyoma of the iris in a Sprague-Dawley rat

A leiomyoma of the iris was composed of bundles of spindle-shaped cells with abundant myoglial fibres and represents the first observation of this rare tumour in a rat.

Clinical course of renal adenocarcinoma associated with hypercupraemia in a horse

A four-year-old shire mare with haematuria, colic, terminal weight loss and an abdominal mass had a large unilateral renal adenocarcinoma. Clinical signs were monitored for 11 months. Increased serum copper concentrations were measured on two occasions. Hypercupraemia is discussed as a possible paraneoplastic change.

Asymptomatic microhematuria and urologic disease. A population-based study

Asymptomatic microhematuria is a common finding, occurring in 13% of adult men and postmenopausal women in Rochester, Minn. Previous recommendations to perform cystoscopic and excretory urographic examinations on all patients with this finding were based on findings in referred patients. In the present population-based study, the frequency of serious urologic disease in patients with asymptomatic microhematuria was 2.3%; only 0.5% had bladder or renal cell carcinoma. Urologic malignant lesions occurred more frequently in the elderly. There was a trend toward more serious diseases in those with higher grades of hematuria. Complete urologic investigation of all patients with any degree of asymptomatic microhematuria cannot be recommended. The presence of other risk factors should be considered in opting for further evaluation.

A role for transglutaminase in glucose-stimulated insulin release from the pancreatic beta-cell

Preincubation of rat islets of Langerhans with the potent inhibitors of islet transglutaminase activity, monodansylcadaverine (30-100 microM) and N-(5-aminopentyl)-2-naphthalenesulphonamide (100-200 microM), led to significant inhibition of glucose-stimulated insulin release from islets. In contrast, the respective N'-dimethylated derivatives of these two compounds, which did not inhibit islet transglutaminase activity, were much less effective as inhibitors of glucose-stimulated insulin release. None of the compounds inhibited rat spleen protein kinase C activity at concentrations which gave rise to inhibition of glucose-stimulated insulin release. When tested for their effects on calmodulin-stimulated bovine heart phosphodiesterase activity, of the compounds that inhibited insulin release, only monodansylcadaverine did not act as an effective antagonist of calmodulin at concentrations (up to 50 microM) that gave rise to significant inhibition of glucose-stimulated insulin release. Furthermore, at 50 microM, monodansylcadaverine did not inhibit methylation of islet lipids. The inhibition of glucose-stimulated insulin release by monodansylcadaverine is therefore likely to be attributable to its interference with islet transglutaminase activity. The sensitivity of islet transglutaminase to activation by Ca2+ was investigated by using a modified assay incorporating dephosphorylated NN'-dimethylcasein as a substrate protein. The Km for Ca2+ obtained (approx. 3 microM) was an order of magnitude lower than previously reported for the islet enzyme [Bungay, Potter & Griffin (1984) Biochem. J. 219, 819-827]. Mg2+ (2 mM) was found to have little effect on the sensitivity of the enzyme to Ca2+. Investigation of the endogenous substrate proteins of islet transglutaminase by using the Ca2+-dependent incorporation of [14C]methylamine into proteins of islet homogenates demonstrated that most of the incorporated radiolabel was present in cross-linked polymeric aggregates which did not traverse 3% (w/v) acrylamide gels. The radiolabelled polymeric aggregates were present in 71 000 g-sedimented material of homogenates, and their formation was transglutaminase-mediated. These findings provide new evidence for the involvement of islet transglutaminase in the membrane-mediated events necessary for glucose-stimulated insulin release.

Strain-related susceptibility to nephrotoxicity induced by aspirin and phenylbutazone in rats

Single doses of aspirin induce scattered foci of necrosis of proximal tubules in some strains of rats, whereas acute or sub-acute administration of phenylbutazone causes renal papillary necrosis. Initially, using Sprague-Dawley rats of CFY and CD strains, it became clear that these rats were not as susceptible to these drugs as the literature suggested. Aspirin-induced necrosis was apparently sex-related, being seen in females but could be induced by hormone treatment in males. Male Wistar and Sprague-Dawley rats had reacted differently to administration of phenylbutazone for two weeks. Two experiments were performed with four rat strains: Wistar, Lister-Hooded, Sprague-Dawley, and Fischer-344. The rats were six weeks old at the start of the experiments. Five males and five females of each strain were gavaged with either a single dose of 1,000 mg/kg of aspirin or 200 mg/kg phenylbutazone once daily for four weeks. The drugs were suspended in methylcellulose, which was given to equal numbers of control male and female rats in each experiment. The rats were maintained under standard conditions. Blood and 18-hour overnight urine samples were collected prior to sacrifice. There were no strain-related differences in the types of renal lesions seen, however there were differences in the degrees of responses to the two drugs. With aspirin the female Fischer-344 rats were the most susceptible showing necrosis of proximal tubules of both kidneys and markedly elevated urinary protein concentration and gamma-GT activity. Other females showed less change. Male rats were affected only slightly and males of the Wistar strain were not.(ABSTRACT TRUNCATED AT 250 WORDS)

Age-related variations in renal structure and function in Sprague-Dawley rats

Data from 500 male and 500 female Sprague-Dawley rats used as controls in studies performed at Huntingdon Research Centre to assess the safety of drugs were sampled at 17, 30, 56, 82, or 108 weeks of age. Plasma urea nitrogen levels remained constant, except in aged males. Aging caused increased proteinuria and decreased urinary concentrating ability, in addition to increased size, weight, and degree of cortical scarring of kidneys. Chronic progressive nephropathy, first seen histopathologically at 30 weeks of age, accounted for these changes and ultimately affected 81% of male and 44% of female rats. One-fifth of two-year-old male rats had diffuse parenchymal damage and a small number also had secondary hyperparathyroidism. Other notable changes included basophilic (often colloid-filled) cortical tubules, mononuclear cell infiltrations, parenchymal and pelvic mineralization, urothelial hyperplasia, and pyelonephritis. Miscellaneous low incidence findings included one lipomatous tumour and generalized lymphosarcoma.

Fecal blood levels in health and disease. A study using HemoQuant

We tested HemoQuant, a quantitative assay of fecal blood based on the fluorescence of heme-derived porphyrin, in 106 healthy volunteers, 170 patients with gastrointestinal symptoms but with normal diagnostic studies, 44 patients with gastrointestinal cancer, 75 patients with benign polyps, and 374 patients with a variety of other benign gastrointestinal lesions, including ulcers and erosions. In 98 per cent of the healthy volunteers, fecal hemoglobin concentrations were less than 2 mg per gram of stool. Levels were similarly low in stools from patients with symptoms and normal studies and in patients with relatively minor benign lesions. Within these groups, levels were slightly higher in those who had ingested red meat or aspirin. The fecal hemoglobin concentration was higher in patients with gastrointestinal cancer than in any other group, and 97 per cent of those with colorectal cancer had levels above 2 mg per gram. The sensitivity of HemoQuant was significantly greater than that of the guaiac test Hemoccult, particularly when heme was degraded or stools were dry. Intestinal degradation of heme to porphyrin can be measured separately by HemoQuant, and was greater when bleeding was from proximal lesions rather than distal ones. We conclude that HemoQuant is a more sensitive measure of gastrointestinal bleeding than Hemoccult, and that its capacity to measure degraded heme may be useful in indicating the anatomic site of bleeding.

HemoQuant, a new quantitative assay for fecal hemoglobin. Comparison with Hemoccult

HemoQuant, an assay based on heme-derived porphyrin, quantifies both total fecal hemoglobin ant that fraction already converted to porphyrin by gut flora (the intestinal converted fraction). Recovery by HemoQuant of blood added to stools exceeded 99% and was not affected by ascorbic acid, iron, or other additives. HemoQuant was used to evaluate the performance of Hemoccult on 1018 stools. Hemoccult sensitivity differed widely, remaining negative with up to 42.5 mg hemoglobin per gram of stool (about 43 mL/d of blood) but positive with only 0.04 mg of hemoglobin per gram of stool. Driest stools tended to be Hemoccult-negative and the wettest Hemoccult-positive. Hemoccult-negative stools became positive after aqueous dilution independent of hemoglobin concentration. The intestinal converted fraction, not detected by guaiac tests, often constituted most of the fecal hemoglobin equivalents and was significantly higher in Hemoccult-negative than in Hemoccult-positive stools. Hemoccult lost reactivity during fecal storage due to progressive heme degradation. Frequent false-negative and false-positive reactions of Hemoccult were explained largely by variations in stool liquidity and heme degradation.

Gastrointestinal blood loss and anemia in runners

Iron deficiency, with or without anemia, occurs commonly in long-distance runners, but the cause is unknown. The recent development of a simple quantitative assay for fecal hemoglobin, HemoQuant , allowed us to study whether gastrointestinal bleeding occurs in runners. Blood and stool samples were collected from 24 runners before and after a race of 10 to 42.2 km and from age- and sex-matched, nonrunning controls. The mean blood hemoglobin level and hematocrit were significantly lower in runners than in controls. Serum ferritin levels were below normal in 4 runners but in no controls. Fecal hemoglobin levels increased in 20 of 24 runners (p less than 0.01) after a race. Mean fecal hemoglobin level was 1.08 mg/g (range, 0.11 to 2.36) in controls and 0.99 mg/g (0.18 to 2.41) in runners before a race, but peaked at 3.96 mg/g (0.37 to 43.20) after a race. Competitive long-distance running induces gastrointestinal blood loss and may contribute to iron deficiency.