The molecular landscape and associated clinical experience in infant medulloblastoma: prognostic significance of second-generation subtypes.

AIMS: Biomarker-driven therapies have not been developed for infant medulloblastoma (iMB). We sought to robustly sub-classify iMB, and proffer strategies for personalized, risk-adapted therapies. METHODS: We characterized the iMB molecular landscape, including second-generation subtyping, and the associated retrospective clinical experience, using large independent discovery/validation cohorts (n = 387). RESULTS: iMBGrp3 (42%) and iMBSHH (40%) subgroups predominated. iMBGrp3 harboured second-generation subtypes II/III/IV. Subtype II strongly associated with large-cell/anaplastic pathology (LCA; 23%) and MYC amplification (19%), defining a very-high-risk group (0% 10yr overall survival (OS)), which progressed rapidly on all therapies; novel approaches are urgently required. Subtype VII (predominant within iMBGrp4 ) and subtype IV tumours were standard risk (80% OS) using upfront CSI-based therapies; randomized-controlled trials of upfront radiation-sparing and/or second-line radiotherapy should be considered. Seventy-five per cent of iMBSHH showed DN/MBEN histopathology in discovery and validation cohorts (P < 0.0001); central pathology review determined diagnosis of histological variants to WHO standards. In multivariable models, non-DN/MBEN pathology was associated significantly with worse outcomes within iMBSHH . iMBSHH harboured two distinct subtypes (iMBSHH-I/II ). Within the discriminated favourable-risk iMBSHH DN/MBEN patient group, iMBSHH-II had significantly better progression-free survival than iMBSHH-I , offering opportunities for risk-adapted stratification of upfront therapies. Both iMBSHH-I and iMBSHH-II showed notable rescue rates (56% combined post-relapse survival), further supporting delay of irradiation. Survival models and risk factors described were reproducible in independent cohorts, strongly supporting their further investigation and development. CONCLUSIONS: Investigations of large, retrospective cohorts have enabled the comprehensive and robust characterization of molecular heterogeneity within iMB. Novel subtypes are clinically significant and subgroup-dependent survival models highlight opportunities for biomarker-directed therapies.

Characterization and simulation of soft gamma-ray mirrors for their use with spent fuel rods at reprocessing facilities.

The use of a grazing incidence optic to selectively reflect K-shell fluorescence emission and isotope-specific lines from special nuclear materials is a highly desirable nondestructive analysis method for use in reprocessing fuel environments. Preliminary measurements have been performed, and a simulation suite has been developed to give insight into the design of the x ray optics system as a function of the source emission, multilayer coating characteristics, and general experimental configurations. The experimental results are compared to the predictions from our simulation toolkit to illustrate the ray-tracing capability and explore the effect of modified optics in future measurement campaigns.

Type II diabetes and oral health: perceptions among adults with diabetes and oral/health care providers in Ghana.

OBJECTIVE: This study sought to examine oral health beliefs and attitudes, and utilisation of oral health care services among individuals with diabetes and health professionals who serve them in Ghana. BASIC RESEARCH DESIGN: A qualitative study using grounded theory was conducted. CLINICAL SETTING: University of Ghana Dental School at Korle Bu, University of Ghana School of Public Health, National Diabetes Research and Management Centre at Korle Bu, and New York University College of Dentistry. PARTICIPANTS: A convenience sample of 59 patients comprised 7 focus groups conducted in either Twi or English. Seven key informant interviews with healthcare professionals and one spiritual leader were completed. RESULTS: Data from the focus groups and interviews reveal: 1, half of the participants with diabetes have oral manifestations (e.g., bleeding gums) and participants are generally unaware of interrelationship between diabetes and oral health; 2, dental treatment utilisation is minimal and associated almost exclusively with reparative and emergency care; and 3, medical health providers do not acknowledge the interrelationship between oral health and diabetes nor do they incorporate oral health issues into diabetes screening/treatment. CONCLUSION: Oral health knowledge and practices are limited among patients with diabetes in Accra, Ghana. Collaborative efforts for in-service education and training for oral health and medical professionals may be beneficial in serving the oral and general health care needs as well as improving the oral health-related quality of life of Ghanaians with diabetes.

A prospective, randomised, controlled trial of the use of drains in total hip arthroplasty.

The routine use of surgical drains in total hip arthroplasty remains controversial. They have not been shown to decrease the rate of wound infection significantly and can provide a retrograde route for it. Their use does not reduce the size or incidence of post-operative wound haematomas. This prospective, randomised study was designed to evaluate the role of drains in routine total hip arthroplasty. We investigated 552 patients (577 hips) undergoing unilateral or bilateral total hip arthroplasty who had been randomised to either having a drain for 24 hours or not having a drain. All patients followed standardised pre-, intra-, and post-operative regimes and were independently assessed using the Harris hip score before operation and at six, 18 and 36 months follow-up. The rate of superficial and deep infection was 2.9% and 0.4%, respectively, in the drained group and 4.8% and 0.7%, respectively in the undrained group. One patient in the undrained group had a haematoma which did not require drainage or transfusion. The rate of transfusion after operation in the drained group was significantly higher than for undrained procedures (p < 0.042). The use of a drain did not influence the post-operative levels of haemoglobin, the revision rates, Harris hip scores, the length of hospital stay or the incidence of thromboembolism. We conclude that drains provide no clear advantage at total hip arthroplasty, represent an additional cost, and expose patients to a higher risk of transfusion.

Reflective multilayer optic as hard X-ray diagnostic on laser-plasma experiment.

A multilayer-based optic was tested for use as an X-ray diagnostic on a laser-plasma experiment. The multilayer optic was employed to selectively pass X-rays between 55 and 100 keV. An order of magnitude improvement in signal-to-noise ratio is achieved compared to a transmission crystal spectrometer. A multilayer response model, taking into account the source size and spectral content, is constructed and the outlook for application above 500 keV is briefly discussed. LLNL-JRNL-664311.

Fetuin: the bovine homologue of human alpha 2HS glycoprotein.

The fetal protein fetuin has previously been considered to be confined to species of the order Artiodactyla (cattle, sheep, etc.) in spite of demonstrable biological in vitro effects in tissues of other species [(1983) Comp. Biochem. Physiol. 76A, 241-245]. We have determined the partial amino acid sequence of bovine fetuin and compared it with the published sequence of human alpha 2HS glycoprotein. The N-terminal 105 residues and a segment aligned with residues 170-225 of alpha 2HS glycoprotein revealed 109 of 161 residues to be identical between the two proteins (68% homology). Mouse polyclonal antibodies to fetuin, and trypsin digest fragments of this protein have been prepared and used for a comparison of native and digested proteins. Polyclonal antibodies to native protein showed little if any cross reactivity. However, antibodies to trypsin digest fragments of fetuin showed obvious cross reactivity with alpha 2HS.

A new intracellular serine protease inhibitor expressed in the rat pituitary gland complexes with granzyme B.

We have cloned a novel serpin (raPIT5a) from a rat pituitary cDNA library which is structurally related to members of the ovalbumin subfamily of serine protease inhibitors. This new cDNA encodes a 374-amino acid protein, designated raPIT5a. raPIT5a was expressed in specific cells in the intermediate and anterior lobes of the pituitary. Recombinant raPIT5a was not secreted suggesting raPIT5a functions to inhibit intracellular proteases. Recombinant raPIT5a formed an SDS-stable complex with human granzyme B, a serine protease which induces apoptosis by activating members of the caspase enzyme family. These data suggest raPIT5a may have a role in regulating granzyme B or related enzymes and apoptosis in the pituitary gland.

Human tears: osmotic characteristics.

Using a freezing point depression method, requiring volumes of only 200 nanoliters, the osmolalities of 324 tear samples collected at consecutive 10-minute intervals throughout 8.5-hour periods from each of six healthy young adults were measured. The population mean was found to be 318 mOsm/kg, with a population median of 315 mOsm/kg. Individual subject means ranged from 310 to 334 mOsm/kg. Short-term oscillations were observed for all subjects, with a net positive rate toward hypertonicity for the population of 1.43 mOsm/kg X hr-1 as the day progressed. Two subjects did demonstrate mild net rates of decrease, however. All eyes in the study were asymptomatic, suggesting a broader range of tear osmotic pressure among normals than previously suspected.

Aerobic responses of the cornea to alkali measured in vivo.

With the use of a micropolarographic system, the effects of a series of unbuffered sodium hydroxide concentrations on oxygen uptake by the corneal epithelium of rabbit were measured in vivo. Based on an exposure model of 10 sec. followed by a saline rinse, concentrations of greater than 0.10 N were found to cause an abrupt and severe decline in oxygen uptake, with oxygen flux responses associated with 0.13 N and greater being indistinguishable 10 min later from those of a cornea completely denuded of epithelium. Initial flux variations, characteristic of exposure responses to concentrations of 0.10 N or less, gradually diminished, however, stabilizing within 1 hr to levels not significantly different (P less than 0.01) from pre-exposure fluxes or those of saline controls.

Human tear glucose.

By means of a photometric method, the glucose concentrations of 875 human tear samples were analyzed. The arithmetic mean for the total population was 7.5 mg/dl, although significant differences in average concentration among individuals were found (3.4 to 12.7 mg/dl). Although the total population mode, 3.2 mg/dl, did fall within range limits often cited in the current literature, the higher arithmetic mean found here is attributed to special precautions taken to minimize reflex tear inclusion, to corrections made for effects of processing delay, and to the assembly of more extensive and time-balanced sample bases (an average of 73 specimens taken hourly throughout the waking periods of 5 days) for each individual studied. The population diurnal profile (i.e., the average of 60 individual profile days constructed here) was found to have some phase characteristics resembling those of serum glucose population profiles in the literature.

Human tear responses to alkali.

With the use of a closed-chamber microelectrode system, the buffering capacities of over 100 tear samples were measured in response to alkali challenge of several strengths. Although distinctive variations were found among the seven subjects studied, a substantially greater buffer capacity was consistently noted in all their tear responses to pH conditions of near 10 and above. These results are consistent with the early observations of Friedenwald, who demonstrated the buffering capacity of corneal tissue when challenged in this higher pH range, and may here be due to the onset of protein denaturation in the tears.

Aerobic responses of the cornea to ophthalmic preservatives, measured in vivo.

A micropolarographic system was used to measure the effects of several concentrations of benzalkonium chloride and thimerosal on oxygen uptake by the cornea. Although the threshold of 0.01% found for benzalkonium chloride generally agreed with other criteria (e.g., clinical and histologic) in the current literature, the threshold for thimerosal was somewhat higher, 1.0%, indicating a substantially greater aerobic activity tolerance of the cornea to initial direct exposures of that agent then to benzalkonium chloride.

Buffering in human tears: pH responses to acid and base challenge.

The buffering capacity of tears collected from six young, healthy subjects was assessed using a microtitration technique. Each subject provided, on six separate occasions, about 100 microliter of tears, collected in small amounts and with minimal mechanical stimulation over several hours. The pH of the total stirred pool of tears from each subject was determined at the outset. This pool of tears was then divided into two equal volume aliquots, the pH of each being determined following each titration step of one of them with acid, and of the other with base. In all, 28 titration steps across the acid-base spectrum were completed for each patient pool collected. A total of 1044 tear pH measurements were made, all being done in a closed, temperature stabilized (36 degrees C) microelectrode chamber having an accuracy of within 0.04 pH units. For a comparative reference, an identical titration procedure was used on degassed, demineralized distilled water (348 pH determinations). Buffering capacity was found to show considerable intersubject variations, but in all cases the effect was more pronounced and more uniform following acid titration. Local zones of enhanced buffering across the pH spectrum could be identified, presumably reflecting the multiple buffering components (bicarbonate, protein and others) present in tear fluid.

The thickness of the human precorneal tear film: evidence from reflection spectra.

PURPOSE: Interferometric methods have considerable potential for studying the thickness of layers of the human tear film and cornea because of their ability to make noninvasive, accurate, and rapid measurements. However, previous interferometric studies by Prydal and Danjo yielded tear thickness values near 40 and 11 microm, respectively, considerably greater than estimates made by invasive methods of 4 to 8 microm. Using a modified version of Danjo's method, interference effects from the tear film and cornea were studied, with the aim of correlation with known structure and optical properties of the cornea and hence determining the most probable value of tear film thickness. METHODS: Reflectance spectra from the human cornea were measured at normal incidence. These spectra show oscillations whose maxima correspond to constructive interference between light reflected from the air surface and from some deeper surface. The frequency of these spectral oscillations is proportional to the thickness of the layer between the air surface and the second surface. Therefore, Fourier analysis of reflectance spectra can be used to determine the thickness of layers of the tear film and cornea. In the main experiment, 36 low-resolution spectra were obtained from six normal eyes for measuring thickness up to 100 microm. Control experiments included measurements of the time course of thickness changes and high-resolution spectra for measuring thickness up to 1000 microm. RESULTS: For the main experiment, in the thickness range 1 to 100 microm, the strongest peak in the Fourier transform was near 3 microm (range, 1.5-4.7 microm) beneath the air surface. In the range 20 to 100 microm, the strongest peak was near 55 microm (range, 50-59 microm) for all 36 spectra; none were in Prydal's range near 40 microm. This 55-microm peak is consistent with a reflection from the basement membrane of the epithelium. Time course measurements after a blink show that the 3-microm peak is not an artifact. High-resolution spectra gave a peak near 510 microm, corresponding to the complete thickness of the cornea (plus tear film). This peak had a contrast similar to that of the 3-microm peak. CONCLUSIONS: These studies did not confirm Prydal's estimate of approximately 40 microm. Nor were there prominent peaks near Danjo's value of approximately 11 microm, except in cases of probable reflex tears. Because the reflection at the aqueous-mucus boundary would be expected to be weaker than that from the epithelial surface, the 3-microm peak is unlikely to correspond to the aqueous layer (rather than the complete tear film). The proposal that the 3-microm peak corresponds to a reflection from the front of the cornea is supported by the demonstration of a peak of similar contrast from the back of the cornea. Thus, the current evidence consistently supports a value of approximately 3 microm for the thickness of the human precorneal tear film.

Human tear buffering capacity.

With the use of a closed chamber microelectrode system, we measured the relative buffering capacities of 490 human tear samples from young healthy adults. The buffering capacities of the 457 waking-hour samples did show small but regular oscillations that were similar to those previously reported for blood and tear pH, but only rarely did the buffering capacity of one sample approach double that of another. The buffering capacities of 33 tear samples, associated with periods of prolonged eye closure (sleep), were not significantly different (P less than 0.5) from those of the open eye.

Human tear osmotic pressure: diurnal variations and the closed eye.

Using a micro-osmometry technique, 450 nonreflex tear samples were collected hourly from six subjects throughout their waking hours, and on initial opening of the eyes following six to eight hours of sleep. While the waking day mean found for this population agreed closely with current values in the literature, considerable variation did occur among individuals, both in their mean as well as in their hour-to-hour levels. The prolonged lid closure condition resulted in a considerable decrease in tear osmotic pressure and was found to be significantly different from the open-eye condition (P less than .001). No significant differences could be shown however between findings for men and women for either condition, and no consistent impact of food or fluid intake could be demonstrated.

Human tear pH. Diurnal variations.

Using a closed chamber microelectrode system, the tear pH levels of sixteen subjects were monitored throughout the waking extent of five days. In addition to the absolute mean pH differences found among subjects, diurnal patterns of pH change could be identified for the majority. The amplitudes and periods of these cycloid patterns, however, were distinctive to each individual. Also, tear pH levels following periods of prolonged eye closure were found to be notably more acid than those associated with the waking hours.

Individual growth curve standards in triplets: prediction of third-trimester growth and birth characteristics.

We investigated the ability of Rossavik growth models, determined from measurements obtained before 24 weeks (head circumference [HC], abdominal circumference [AC], femur diaphysis length, and estimated fetal weight [EFW]) or 25 weeks (thigh circumference), to predict third-trimester growth and birth characteristics in normally growing triplets. Comparisons of coefficient c values for six anatomical measurements indicated no statistically significant differences in the second-trimester growth of triplets, twins, and singletons. Third-trimester triplet values for HC, AC, and femur diaphysis length were predicted with an accuracy of +/- 6-8%. For thigh circumference and EFW, the comparable values were +/- 17 and +/- 15%, respectively. The HC at birth was predicted without bias; the random error was approximately -27 to 9.0%. Weight, AC, and thigh circumference were systematically overestimated (16.5, 20.9, and 16.3%, respectively). After correction for systematic errors, these characteristics could be predicted with random errors of -13.0 to 9.5% (weight), -12.0 to 2.8% (AC), and -16.7 to 11.3% (thigh circumference). Growth Potential Realization Index values had means of approximately 100% and ranges from 90-121%. The mean triplet value of the Neonatal Growth Assessment Score was 13.6, ranging from 2.8-26.5. These results are similar to those for singletons and twins and indicate that individual assessment of growth in triplets can be performed with the same methods used for both singletons and twins.

Tonicity of human tear fluid sampled from the cul-de-sac.

A 'freezing point' depression technique was used to determine the osmolality of 384 samples of tear fluid originating from the middle of the lower tear prism and the lower cul-de-sac of one eye of each of 12 young adults. Tear fluid from the cul-de-sac (mean 341.0 mosm/kg) was found overall to be significantly hypertonic (p less than 0.0001) relatively to fluid from the tear prism (mean 315.5 mosm/kg). However, the difference between the two sampling sites was highly variable between individuals, ranging from a maximum mean site difference of 64.5. mosm/kg for one of the six cul-de-sacs found to be significantly hypertonic, to a mean site difference of 25.0 mosm/kg for one of the two cul-de-sacs found to be significantly hypotonic. These results suggest that a unique localised tear environment exists inside the lower cul-de-sac, which has several clinical consequences--for example, for pharmaceutical absorption, ocular microbiology, and hydrophilic contact lens performance.

Corneal oxygenation: blink frequency as a variable in rigid contact lens wear.

Using a micropolarographic system, we measured the responses of six human corneas to nine oxygen exposure conditions: to air (continuous open-eye) with no contact lens in place, and to eight interblink intervals (1, 2, 3, 4, 5, 6, 7, and 300 s durations) with an oxygen impermeable lens in place. The corneal oxygen uptake rates immediately following each of those conditions were direct indices of tear bulk-flow exchange under a rigid contact lens as an oxygen route. Greatest efficiencies in reducing corneal oxygen demand were associated with the two highest blink frequencies examined (namely, for interblink intervals of 2 s or less). Even at those frequencies oxygen demands ranging from 4 to 6 times the open-eye, non-wearing, baseline rate for each eye typically occurred, clearly justifying the need for a supplementary oxygenation route, for example, directly through rigid contact lens materials having inherently high oxygen permeabilities.