Electronic structure of (In,Mn)As quantum dots buried in GaAs investigated by soft-x-ray ARPES.

Electronic structure of a molecular beam epitaxy-grown system of (In,Mn)As quantum dots (QDs) buried in GaAs is explored with soft-x-ray angle-resolved photoelectron spectroscopy (ARPES) using photon energies around 1 keV. This technique, ideally suited for buried systems, extends the momentum-resolving capabilities of conventional ARPES with enhanced probing depth as well as elemental and chemical state specificity achieved with resonant photoexcitation. The experimental results resolve the dispersive energy bands of the GaAs substrate buried in ∼2 nm below the surface, and the impurity states (ISs) derived from the substitutional Mn atoms in the (In,Mn)As QDs and oxidized Mn atoms distributed near the surface. An energy shift of the Mn ISs in the QDs compared to (In,Mn)As DMS is attributed to the band offset and proximity effect at the interface with the surrounding GaAs. The absence of any ISs in the vicinity of the VBM relates the electron transport in (In,Mn)As QDs to the prototype (In,Mn)As diluted magnetic semiconductor. The SX-ARPES results are supported by measurements of the shallow core levels under variation of probing depth through photon energy. X-ray absorption measurements identify significant diffusion of interstitial Mn atoms out of the QDs towards the surface, and the role of magnetic circular dichroism is to block the ferromagnetic response of the (In,Mn)As QDs. Possible routes are drawn to tune the growth procedure aiming at practical applications of the (In,Mn)As based systems.

Short communication: Effect of canola meal use as a protein source in a starter mixture on feeding behavior and performance of calves during the weaning transition.

The aim of this study was to determine the effect of canola meal use as a protein source in a starter mixture (SM) on feeding behavior and performance of calves during weaning transition. A total of 36 female Holstein calves of a mean age 14.9±1.6 d and body weight 40.1±4.2 kg (mean ± SD) were allocated to 1 of 3 treatments differing in the main source of protein for the SM (12 calves per treatment): (1) soybean meal (TSBM); (2) soybean meal and canola meal (TSBM/TCM); and (3) canola meal (TCM). The SM was offered for ad libitum consumption beginning on the first day of the study, whereas milk replacer (MR) was fed in amounts equal to 900 g (as fed) per day from d 1 to 35 and 450 g/d from d 36 to 42 of the study. Calves were completely weaned on d 43 of the study (57.9±1.6 d of age; mean ± SD), and their performance was monitored for an additional 2 wk. Calf body weight was recorded weekly, and MR and SM intake and fecal fluidity were recorded daily. Feeding behavior of calves during weaning transition, including frequency (no./d), time (min/d), and rate (g/min) of eating the SM as well as frequency and time of drinking water, was monitored on 6 calves per treatment for 2 consecutive days before MR step-down (d 34-35), at MR step-down (d 41-42), and after weaning (d 48-49 of study). Starter mixture intake tended to be higher for TSBM calves as compared with TSBM/TCM calves from d 1 to 35 of the study but was not different between TSBM and TCM calves and was not different between treatments in the whole study period. Calves from TCM treatment had reduced average daily gain (ADG) and feed efficiency (g of ADG/kg of dry matter intake) and a higher fecal score in the period from d 1 to 35 of the study and had lower feed efficiency and tended to have lower ADG in the whole study period as compared with TSBM calves. Average daily gain and feed efficiency did not differ between TSBM and TSBM/TCM calves. Frequency of eating the SM and drinking water as well as time and rate of eating the SM and time of drinking water did not differ between treatments. It is concluded that presence of canola meal in a SM does not affect feeding behavior and performance of calves during weaning transition but has a negative effect on ADG, feed efficiency, and number of days with diarrhea during the preweaning phase of rearing.

Brain protein oxidation in age-related neurodegenerative disorders that are associated with aggregated proteins.

Protein oxidation, one of a number of brain biomarkers of oxidative stress, is increased in several age-related neurodegenerative disorders or animal models thereof, including Alzheimer's disease, Huntington's disease, prion disorders, such as Creutzfeld-Jakob disease, and alpha-synuclein disorders, such as Parkinson's disease and frontotemporal dementia. Each of these neurodegenerative disorders is associated with aggregated proteins in brain. However, the relationship among protein oxidation, protein aggregation, and neurodegeneration remain unclear. The current rapid progress in elucidation of mechanisms of protein oxidation in neuronal loss should provide further insight into the importance of free radical oxidative stress in these neurodegenerative disorders.

The influence of age and extensive intraductal component histology upon breast lumpectomy margin assessment as a predictor of residual tumor.

PURPOSE: Young age and extensive intraductal component (EIC) histology have been shown to be associated with increased local recurrence in women treated with breast conservation therapy. This study was conducted to determine if the status of the lumpectomy specimen margin consistently predicted for residual tumor burden risk irrespective of these variables. METHODS AND MATERIALS: As part of an institutional prospective approach for breast conservation therapy (BCT), 265 cases with AJCC Stage I/II carcinoma with an initial excision margin that was < or =2 mm or indeterminate were subjected to reexcision. The probability of residual tumor (+RE) was evaluated with respect to tumor size, histopathologic subtype (invasive ductal carcinoma, invasive ductal carcinoma with an EIC, and invasive lobular carcinoma), relative closeness of the measured margin, and the extent of margin positivity graded as focal, minimal, moderate, or extensive. The amount of residual tumor was graded as microscopic, small, medium, or large. All variables were analyzed for patient age < or =45 or >45 years. RESULTS: There was no significant difference in the incidence of a +RE according to age < or =45 versus >45 years when the margin was >0 < or =2 mm. Of the patients aged < or =45 years, the incidence of a +RE with a margin that was positive as compared to >0 < or =2 mm was 71% vs. 23%, respectively (p = 0.002). For women >45 years old, the difference in the incidence of +RE comparing margins that were positive or >0 < or =2 mm was not significant at 50% vs. 40%, respectively (p = 0.23). For all cases in aggregate, age < or =45 years was associated with a greater incidence of +RE as compared to patients aged >45 years with the discrepant incidence of a +RE by age strata most pronounced for focally positive margins (60% vs. 18%;p< or =0.05). In a logistic regression analysis, age (per year, as a continuous variable) and an EIC histology were significantly associated with the probability of a +RE (odds ratio [OR] = 0.80, p = 0.05 and OR = 1.9, p = 0.01, respectively). Tumor size was not significant (p = 0.23). In patients with an EIC histology, margin status is generally less predictive for differences in the incidence of a +RE. Further, the overall magnitude of difference in the incidence of a +RE related to age appears to be minimized when an EIC histology is present. In contrast, for cases classified as having non-EIC histology, there is a near-linear relationship for both age strata with respect to margin status and the incidence of a +RE. When histology is classified as non-EIC, age < or =45 years is consistently associated with a greater risk of residual tumor for all margin status categories. When the extent of margin positivity was graded as focal or minimal, residual tumor was semiquantitatively estimated as a medium/large amount in 33% versus 26% of cases aged < or =45 or >45 years, respectively (p = 0.62). CONCLUSION: For positive lumpectomy specimen margins, younger age is associated with an increased residual tumor risk. An EIC histology appears to be associated with an elevated risk of residual tumor irrespective of age and may undermine the predictive utility of margin status. Therefore, age and an EIC histology should be factored into risk assessments for residual tumor that rely upon margin assessment.

Anterior uveitis in juvenile rheumatoid arthritis.

The ocular and systemic characteristics of 160 patients with anterior uveitis and seronegative juvenile rheumatoid arthritis are reviewed. Chronic uveitis occurred in 131 patients, 76% of whom were girls. Both eyes were involved in 70% of the cases. Band keratopathy occurred in 41% of the eyes, cataract in 42%, and secondary glaucoma in 19%. Only 11 patients had uveitis before the onset of arthritis. Notable correlations included a pauciarticular onset of arthritis in 95% of the patients, and positive tests for antinuclear antibody in 82%. Of 29 patients with acute anterior uveitis, 27 were boys. The inflammation responded well to therapy, and serious complications did not occur. At follow-up 21 patients had typical ankylosing spondylitis, and five had sacroiliitis. The incidence of positive results of tests for HLA-B27 antigen was 94%.

Juvenile arthritis and uveitis.

The association between juvenile arthritis and uveitis is reviewed. Some children with the HLA-B27 related spondyloarthropathies develop anterior uveitis. About 20% of patients with juvenile rheumatoid arthritis (JRA) who are negative for IgM rheumatoid factor develop a frequently bilateral, nongranulomatous chronic anterior uveitis. Risk factors for uveitis in JRA patients are: female gender, pauciarticular onset of arthritis, presence of circulating antinuclear antibodies, and the antigens HLA-DW5 and HLA-DPw2. Uveitis is rare after seven years or more have elapsed from the onset of arthritis. The visual prognosis in patients with uveitis is good in 25% and fair in 50%. The remaining 25% develop visual impairment from complicated cataract and/or secondary inflammatory glaucoma. The potential benefit of cytotoxic agents in the treatment of intractable uveitis is outweighed by the risk of serious side effects. The management of secondary inflammatory glaucoma is unsatisfactory, but the results of treatment of complicated cataracts by lensectomy-vitrectomy are good.

Antioxidant activity of the organotellurium compound 3-[4-(N,N-dimethylamino)benzenetellurenyl]propanesulfonic acid against oxidative stress in synaptosomal membrane systems and neuronal cultures.

Antioxidant activities of 3-[4-(N,N-dimethylamino) benzenetellurenyl]propanesulfonic acid sodium salt (NDBT) were evaluated in solution, red blood cells, synaptosomal membranes, and cultured hippocampal neuronal cells after exposure to peroxynitrite (ONOO(-)) and hydroxyl radicals. The organotellurium compound NDBT possesses significant activity towards hydrogen peroxide and/or the hydroxyl radical in solution, demonstrated by inhibition of hydroxylation of terephthalic acid. In addition, the compound displayed great antioxidant abilities as shown by: reduction of ONOO(-)-induced 2,7-dichlorofluorescein (DCF) fluorescence in synaptosomes; complete prevention of lipid peroxidation in synaptosomes caused by OH radicals (TBARS), and significant prevention of protein oxidation caused by ONOO(-) and OH, indexed by the levels of protein carbonyls in synaptosomes and neuronal cells. The presence of the compound abolished neuronal cell death caused by ONOO(-). Further, the compound was effective in preventing the oxidative changes in synaptosomal membrane protein conformation and crosslinking (EPR spin labeling). Finally, the organotellurium molecule attenuated peroxynitrite-induced, luminol-dependent chemiluminescence in red blood cells--an index of cellular oxidation. These findings demonstrate the great potential of the antioxidant and are consistent with the notion that NDBT may have a role to play in modulating oxidative stress in neurodegenerative disorders, including Alzheimer's disease.

Complications of acute posterior vitreous detachment.

Of 201 patients whose presenting symptoms were acute entoptic phenomena or photopsia, or both, 150 patients had posterior vitreous detachment; 69 patients (46%) had retinal breaks; 18 (12%) had a vitreous hemorrhage without detectable retinal breaks; and two (1.3%) had peripheral retinal hemorrhages without retinal breaks or vitreous hemorrhage. Retinal breaks that occur in eyes in conjunction with acute posterior vitreous detachment are potentially dangerous and there is a possibility of delayed break formation.

Anterior segment complications of retinal photocoagulation.

Seven patients had anterior segment complications following xenon arc retinal photocoagulation. Irreversible keratopathy was induced in two cases; all patients showed evidence of iris injury. The absorption of radiation by the iris was considered the main factor in producing overheating of the anterior segment.

Giant retinal tears.

Of 94 patients (100 eyes) with giant retinal tears, 71.4% of eyes with nontraumatic breaks were myopic and severe retinal pathologic findings were present in 57.3% of fellow eyes. Fifty-five (58%) of 95 treated eyes were successfully reattached; retinal incarceration, attempted in 19 cases, was successful in five. Serious surgical complications were responsible for failure in nine cases (22.5%). The worst prognostic factor were extension of the tear for over two quadrants, myopia of -10 diopters or more, and the presence of aphakia.

Prophylaxis of retinal detachment.

The incidence of retinal detachment after prophylactic treatment is between 1 and 14%. In a series of 701 eyes treated prophylactically with photocoagulation or cryopexy (with and without scleral buckling), incidence of retinal detachment was 4.7%. The incidence of new break formation was 8.0%; in 26 eyes, new breaks were responsible for the subsequent formation of retinal detachment; in seven eyes, retinal detachment resulted from inadequate reaction around the treated retinal break. Twenty eyes suffered a deterioration of visual acuity of two or more lines after treatment. The incidence of complications after photocoagulation was higher than after cryopexy, although there was no significant difference in the efficacy between the two methods.

Penetration of intravenously administered cefoxitin into the aqueous humor of inflamed human eyes.

Intravenous injections of cefoxitin (2-g doses for adults and 40 mg/kg of body weight doses for children) were administered 90 minutes to two hours before surgery. All nine eyes had anterior segment inflammation. Samples of aqueous humor removed during surgery showed a mean cefoxitin concentration of 6.22 micrograms/ml, almost three times the concentration reported in uninflamed eyes. The greater penetration may have been the result of a breakdown in the blood-aqueous barrier. There were no complications.

Methionine residue 35 is important in amyloid beta-peptide-associated free radical oxidative stress.

Amyloid beta-peptide (Abeta), the central constituent of senile plaques in Alzheimer's disease (AD) brain, has been shown to be a source of free radical oxidative stress that may lead to neurodegeneration. In the current study Abeta(1-40), found in AD brain, and the amyloid fragment Abeta(25-35) were used in conjunction with electron paramagnetic resonance spin trapping techniques to demonstrate that these peptides mediate free radical production. The methionine residue in these peptides is believed to play an important role in their neurotoxicity. Substitution of methionine by structurally similar norleucine in both Abeta(1-40) and Abeta(25-35), and the substitution of methionine by valine, or the removal of the methionine in Abeta(25-35), abrogates free radical production and protein oxidation of and toxicity to hippocampal neurons. These results are discussed with relevance to the hypothesis that neurodegeneration in Alzheimer's disease may be due in part to Abeta-associated free radical oxidative stress that involves methionine, and to the use of spin trapping methods to infer mechanistic information about Abeta.

Lensectomy for complicated cataract in juvenile chronic iridocyclitis.

Experience with the removal of complicated cataract by lensectomy in patients with juvenile chronic iridocyclitis (JCI) has so far been limited. The results of lensectomy were reviewed retrospectively in 131 patients with JCI (187 eyes). The mean follow up period was 5 years 4 months. The main operative complication was accidental loss of lens material into the vitreous cavity. The postoperative complications were glaucoma (23 eyes, 15%), phthisis (14 eyes, 8%), secondary pupillary membranes (11 eyes, 6%), and retinal detachment (six eyes, 3%). The incidence of postoperative phthisis was related to the level of intraocular pressure (IOP) at the time of surgery. Twenty four per cent of hypotonous eyes and 4% of eyes with normal or elevated IOP became phthisical. Visual acuity was improved in 77%, was worse in 13%, and unchanged in 10% of eyes. The main causes of a postoperative visual acuity of 6/60 or less were glaucoma, amblyopia, and phthisis. Lensectomy did not appear to alter the course of uveitis.

Intravitreal hyaluronic acid injection. A long-term clinical evaluation.

Healon-H was used in the treatment of seven cases of complicated retinal detachment. A permanent re-attachment was achieved in two cases. No serious ocular complications have been encountered after a follow-up of 4 1/2 years.

Screening for uveitis in juvenile chronic arthritis.

Three hundred and fifteen patients with anterior uveitis associated with juvenile chronic arthritis (JCA) were studied in order to identify the various risk factors for uveitis. Girls were more susceptible to uveitis than boys by a ratio of 3:1. In 94% of cases the uveitis was diagnosed after the development of arthritis. The risk of uveitis was small after seven or more years had elapsed from the onset of arthritis. Patients with pauciarticular onset JCA had the highest risk of uveitis and systemic onset patients the least risk. The presence of circulating antinuclear antibody was also an important marker for an increased risk of uveitis. A regimen for routine screening of patients is suggested.

Vitrectomy technique in anterior segment surgery.

Instruments designed primarily for vitreous surgery were used in 74 anterior segment operations. In each case the instrument was introduced into the eye through a limbal incision. This preliminary report shows that this new approach offers several advantages over conventional methods in selected cases. It is of particular value in the management of presenile and complicated cataracts and in the removal of capsulo-lenticular remnants and pupillary membranes. A larger number of cases and longer follow-up are necessary to define further the specific indications and limitations of this technique.

Retinoblastoma: report of a case with minimal retinal involvement but massive anterior segment spread.

The case is described of a unilateral retinoblastoma in a 7-year-old girl which was initially misdiagnosed because of massive anterior segment involvement in the apparent absence of a retinal lesion. Only on histopathological examination of the enucleated eye was the presence of retinal tumour established, this being confined to two minute foci at the extreme periphery.

Uveitis in juvenile chronic arthritis.

About 20% of patients with juvenile chronic arthritis develop uveitis which is frequently bilateral. Risk factors for uveitis are: female gender, pauciarticular onset of arthritis, presence of circulating antinuclear antibodies, and the antigens HLA-DW5 and HLA-DPw2. The visual prognosis in patients with uveitis is good in 25% and fair in 50%. The remaining 25% develop cataract and/or glaucoma. The management of glaucoma is unsatisfactory, but the results of cataract surgery by lensectomy are good.

Recurrent acute proptosis in atypical systemic lupus erythematosus.

A patient is described who developed acute proptosis, a rare complication of systemic lupus erythematosus, 16 years after the onset of the disease. Treatment with intravenous methylprednisolone produced rapid improvement, but swelling recurred a few days later. Intravenous corticosteroid was again effective and was continued orally without further episodes of proptosis. This patient is unusual in the long period of mild disease before the development of systemic complications, and in having antibodies to nuclear ribonucleoprotein but persistently normal titres of DNA-binding antibodies in her serum.