Observation of Seven Astrophysical Tau Neutrino Candidates with IceCube

We report on a measurement of astrophysical tau neutrinos with 9.7 yr of IceCube data. Using convolutional neural networks trained on images derived from simulated events, seven candidate ν_{τ} events were found with visible energies ranging from roughly 20 TeV to 1 PeV and a median expected parent ν_{τ} energy of about 200 TeV. Considering backgrounds from astrophysical and atmospheric neutrinos, and muons from π^{±}/K^{±} decays in atmospheric air showers, we obtain a total estimated background of about 0.5 events, dominated by non-ν_{τ} astrophysical neutrinos. Thus, we rule out the absence of astrophysical ν_{τ} at the 5σ level. The measured astrophysical ν_{τ} flux is consistent with expectations based on previously published IceCube astrophysical neutrino flux measurements and neutrino oscillations.

Observation of high-energy neutrinos from the Galactic plane

The origin of high-energy cosmic rays, atomic nuclei that continuously impact Earth's atmosphere, is unknown. Because of deflection by interstellar magnetic fields, cosmic rays produced within the Milky Way arrive at Earth from random directions. However, cosmic rays interact with matter near their sources and during propagation, which produces high-energy neutrinos. We searched for neutrino emission using machine learning techniques applied to 10 years of data from the IceCube Neutrino Observatory. By comparing diffuse emission models to a background-only hypothesis, we identified neutrino emission from the Galactic plane at the 4.5σ level of significance. The signal is consistent with diffuse emission of neutrinos from the Milky Way but could also arise from a population of unresolved point sources.

Evidence for neutrino emission from the nearby active galaxy NGC 1068

A supermassive black hole, obscured by cosmic dust, powers the nearby active galaxy NGC 1068. Neutrinos, which rarely interact with matter, could provide information on the galaxy’s active core. We searched for neutrino emission from astrophysical objects using data recorded with the IceCube neutrino detector between 2011 and 2020. The positions of 110 known gamma-ray sources were individually searched for neutrino detections above atmospheric and cosmic backgrounds. We found that NGC 1068 has an excess of 79 − 20 + 22 neutrinos at tera–electron volt energies, with a global significance of 4.2σ, which we interpret as associated with the active galaxy. The flux of high-energy neutrinos that we measured from NGC 1068 is more than an order of magnitude higher than the upper limit on emissions of tera–electron volt gamma rays from this source.

Search for Unstable Sterile Neutrinos with the IceCube Neutrino Observatory

We present a search for an unstable sterile neutrino by looking for a resonant signal in eight years of atmospheric ν_{μ} data collected from 2011 to 2019 at the IceCube Neutrino Observatory. Both the (stable) three-neutrino and the 3+1 sterile neutrino models are disfavored relative to the unstable sterile neutrino model, though with p values of 2.8% and 0.81%, respectively, we do not observe evidence for 3+1 neutrinos with neutrino decay. The best-fit parameters for the sterile neutrino with decay model from this study are Δm_{41}^{2}=6.7_{-2.5}^{+3.9}  eV^{2}, sin^{2}2θ_{24}=0.33_{-0.17}^{+0.20}, and g^{2}=2.5π±1.5π, where g is the decay-mediating coupling. The preferred regions of the 3+1+decay model from short-baseline oscillation searches are excluded at 90% C.L.

Strong Constraints on Neutrino Nonstandard Interactions from TeV-Scale ν_{μ} Disappearance at IceCube

We report a search for nonstandard neutrino interactions (NSI) using eight years of TeV-scale atmospheric muon neutrino data from the IceCube Neutrino Observatory. By reconstructing incident energies and zenith angles for atmospheric neutrino events, this analysis presents unified confidence intervals for the NSI parameter ε_{μτ}. The best-fit value is consistent with no NSI at a p value of 25.2%. With a 90% confidence interval of -0.0041≤ε_{μτ}≤0.0031 along the real axis and similar strength in the complex plane, this result is the strongest constraint on any NSI parameter from any oscillation channel to date.

Search for Relativistic Magnetic Monopoles with Eight Years of IceCube Data

We present an all-sky 90% confidence level upper limit on the cosmic flux of relativistic magnetic monopoles using 2886 days of IceCube data. The analysis was optimized for monopole speeds between 0.750c and 0.995c, without any explicit restriction on the monopole mass. We constrain the flux of relativistic cosmic magnetic monopoles to a level below 2.0×10^{-19}  cm^{-2} s^{-1} sr^{-1} over the majority of the targeted speed range. This result constitutes the most strict upper limit to date for magnetic monopoles with β≳0.8 and up to β∼0.995 and fills the gap between existing limits on the cosmic flux of nonrelativistic and ultrarelativistic magnetic monopoles.

Assessment of microhardness and color stability of micro-hybrid and nano-filled composite resins

Background and Aims

Composite resins are among the most popular restorative dental materials because of the strength and esthetic properties. The goal of this study was to assess the effect of commonly consumed beverages on microhardness and color stability of microhybrid (MH) and nanofilled NF) composite resins.

Material and Methods

240 samples were prepared from the composite material [MH = 120 (material I) and NF = 120 (material II)] and allocated into eight groups of 30 samples. In each group, half of the samples were tested for microhardness and another-half for color stability. After baseline measurements, the samples were immersed in test media, that is, distilled water and beverages (tea, cola, and coffee) for 15 days. Microhardness and color stability measurements were carried out after 15 days to assess the effect of beverages. The color stability and microhardness values were compared and evaluated by analysis of variance (ANOVA) using Tukey's alteration test.

Results

It was reported that the microhardness decreased for both the materials after immersion in all the beverages. Percentage change in microhardness was considerably higher in material II in comparison to the material I in cola drink. Color change was significantly higher in material II compared to material I in water and coffee. Cola drink caused the maximum change in microhardness among all the beverages and coffee caused the maximum color change among all the beverages.

Conclusion

Both composite materials (I and II) showed a reduction in microhardness and change in color after immersion in a different type of test media.

eV-Scale Sterile Neutrino Search Using Eight Years of Atmospheric Muon Neutrino Data from the IceCube Neutrino Observatory

The results of a 3+1 sterile neutrino search using eight years of data from the IceCube Neutrino Observatory are presented. A total of 305 735 muon neutrino events are analyzed in reconstructed energy-zenith space to test for signatures of a matter-enhanced oscillation that would occur given a sterile neutrino state with a mass-squared differences between 0.01 and 100  eV^{2}. The best-fit point is found to be at sin^{2}(2θ_{24})=0.10 and Δm_{41}^{2}=4.5  eV^{2}, which is consistent with the no sterile neutrino hypothesis with a p value of 8.0%.

Characteristics of the Diffuse Astrophysical Electron and Tau Neutrino Flux with Six Years of IceCube High Energy Cascade Data

We report on the first measurement of the astrophysical neutrino flux using particle showers (cascades) in IceCube data from 2010-2015. Assuming standard oscillations, the astrophysical neutrinos in this dedicated cascade sample are dominated (∼90%) by electron and tau flavors. The flux, observed in the sensitive energy range from 16 TeV to 2.6 PeV, is consistent with a single power-law model as expected from Fermi-type acceleration of high energy particles at astrophysical sources. We find the flux spectral index to be γ=2.53±0.07 and a flux normalization for each neutrino flavor of ϕ_{astro}=1.66_{-0.27}^{+0.25} at E_{0}=100  TeV, in agreement with IceCube's complementary muon neutrino results and with all-neutrino flavor fit results. In the measured energy range we reject spectral indices γ≤2.28 at ≥3σ significance level. Because of high neutrino energy resolution and low atmospheric neutrino backgrounds, this analysis provides the most detailed characterization of the neutrino flux at energies below ∼100  TeV compared to previous IceCube results. Results from fits assuming more complex neutrino flux models suggest a flux softening at high energies and a flux hardening at low energies (p value ≥0.06). The sizable and smooth flux measured below ∼100  TeV remains a puzzle. In order to not violate the isotropic diffuse gamma-ray background as measured by the Fermi Large Area Telescope, it suggests the existence of astrophysical neutrino sources characterized by dense environments which are opaque to gamma rays.

Time-Integrated Neutrino Source Searches with 10 Years of IceCube Data

This Letter presents the results from pointlike neutrino source searches using ten years of IceCube data collected between April 6, 2008 and July 10, 2018. We evaluate the significance of an astrophysical signal from a pointlike source looking for an excess of clustered neutrino events with energies typically above ∼1  TeV among the background of atmospheric muons and neutrinos. We perform a full-sky scan, a search within a selected source catalog, a catalog population study, and three stacked Galactic catalog searches. The most significant point in the northern hemisphere from scanning the sky is coincident with the Seyfert II galaxy NGC 1068, which was included in the source catalog search. The excess at the coordinates of NGC 1068 is inconsistent with background expectations at the level of 2.9σ after accounting for statistical trials from the entire catalog. The combination of this result along with excesses observed at the coordinates of three other sources, including TXS 0506+056, suggests that, collectively, correlations with sources in the northern catalog are inconsistent with background at 3.3σ significance. The southern catalog is consistent with background. These results, all based on searches for a cumulative neutrino signal integrated over the 10 years of available data, motivate further study of these and similar sources, including time-dependent analyses, multimessenger correlations, and the possibility of stronger evidence with coming upgrades to the detector.

Constraints on Minute-Scale Transient Astrophysical Neutrino Sources

High-energy neutrino emission has been predicted for several short-lived astrophysical transients including gamma-ray bursts (GRBs), core-collapse supernovae with choked jets, and neutron star mergers. IceCube's optical and x-ray follow-up program searches for such transient sources by looking for two or more muon neutrino candidates in directional coincidence and arriving within 100 s. The measured rate of neutrino alerts is consistent with the expected rate of chance coincidences of atmospheric background events and no likely electromagnetic counterparts have been identified in Swift follow-up observations. Here, we calculate generic bounds on the neutrino flux of short-lived transient sources. Assuming an E^{-2.5} neutrino spectrum, we find that the neutrino flux of rare sources, like long gamma-ray bursts, is constrained to <5% of the detected astrophysical flux and the energy released in neutrinos (100 GeV to 10 PeV) by a median bright GRB-like source is <10^{52.5}  erg. For a harder E^{-2.13} neutrino spectrum up to 30% of the flux could be produced by GRBs and the allowed median source energy is <10^{52}  erg. A hypothetical population of transient sources has to be more common than 10^{-5}  Mpc^{-3}  yr^{-1} (5×10^{-8}  Mpc^{-3}  yr^{-1} for the E^{-2.13} spectrum) to account for the complete astrophysical neutrino flux.

Search for neutrinos from decaying dark matter with IceCube: IceCube Collaboration

With the observation of high-energy astrophysical neutrinos by the IceCube Neutrino Observatory, interest has risen in models of PeV-mass decaying dark matter particles to explain the observed flux. We present two dedicated experimental analyses to test this hypothesis. One analysis uses 6 years of IceCube data focusing on muon neutrino 'track' events from the Northern Hemisphere, while the second analysis uses 2 years of 'cascade' events from the full sky. Known background components and the hypothetical flux from unstable dark matter are fitted to the experimental data. Since no significant excess is observed in either analysis, lower limits on the lifetime of dark matter particles are derived: we obtain the strongest constraint to date, excluding lifetimes shorter than10 28 s at 90% CL for dark matter masses above 10 TeV .

Elevated plasma ferritin in elderly individuals with high neocortical amyloid-β load

Ferritin, an iron storage and regulation protein, has been associated with Alzheimer's disease (AD); however, it has not been investigated in preclinical AD, detected by neocortical amyloid-β load (NAL), before cognitive impairment. Cross-sectional analyses were carried out for plasma and serum ferritin in participants in the Kerr Anglican Retirement Village Initiative in Aging Health cohort. Subjects were aged 65-90 years and were categorized into high and low NAL groups via positron emission tomography using a standard uptake value ratio cutoff=1.35. Ferritin was significantly elevated in participants with high NAL compared with those with low NAL, adjusted for covariates age, sex, apolipoprotein E ɛ4 carriage and levels of C-reactive protein (an inflammation marker). Ferritin was also observed to correlate positively with NAL. A receiver operating characteristic curve based on a logistic regression of the same covariates, the base model, distinguished high from low NAL (area under the curve (AUC)=0.766), but was outperformed when plasma ferritin was added to the base model (AUC=0.810), such that at 75% sensitivity, the specificity increased from 62 to 71% on adding ferritin to the base model, indicating that ferritin is a statistically significant additional predictor of NAL over and above the base model. However, ferritin's contribution alone is relatively minor compared with the base model. The current findings suggest that impaired iron mobilization is an early event in AD pathogenesis. Observations from the present study highlight ferritin's potential to contribute to a blood biomarker panel for preclinical AD.

Delay and attrition before treatment initiation among MDR-TB patients in five districts of Gujarat, India

Setting: Gujarat, a state in west India. Background: Although treatment initiation has been improving among patients diagnosed with multidrug-resistant tuberculosis (MDR-TB) in programme settings, it has still not reached 100%. Objectives: To determine pre-treatment attrition (not initiated on treatment within 6 months of diagnosis), delay in treatment initiation (>7 days from diagnosis) and associated factors among MDR-TB patients diagnosed in 2014 in five selected districts served by two genotypic drug susceptibility testing (DST) facilities and a drug-resistant TB centre in Gujarat. Design: This was a retrospective cohort study involving record review. Results: Among 257 MDR-TB patients, pre-treatment attrition was seen in 20 (8%, 95%CI 5-12). Patients with 'follow-up sputum-positive' as their DST criterion and sputum smear microscopy status 'unknown' at the time of referral for DST were less likely to be initiated on treatment. The median delay to treatment initiation was 8 days (interquartile range 6-13). Patients referred for DST from medical colleges were more likely to face delays in treatment initiation. Conclusion: The Gujarat TB programme is performing well in initiating laboratory-confirmed MDR-TB patients on treatment. However, there is further scope for reducing delay.

Pretreatment sputum smear grade and smear positivity during follow-up of TB patients in Ahmedabad, India

In Ahmedabad, India, a retrospective record review was undertaken among 2842 sputum smear-positive tuberculosis patients registered for treatment from April to September 2011 to assess the association of pretreatment sputum smear grade with sputum positivity and the additional yield of a second sputum sample during each follow-up examination. Respectively 39%, 26%, 28% and 7% of patients had pretreatment sputum grade 3+, 2+, 1+ and scanty. The higher the pretreatment sputum grade, the higher the proportion found positive during various follow-up periods. Overall, the additional yield of the second sputum sample was <2%; it did not vary with pretreatment smear grading.

Ability of Bottle Cap Color to Facilitate Accurate Patient-Physician Communication Regarding Medication Identity in Patients with Glaucoma

PURPOSE

To determine the accuracy of patient-physician communication regarding topical ophthalmic medication use based on bottle cap color, particularly among individuals who may have acquired color vision deficiency from glaucoma.

DESIGN

Cross-sectional, clinical study.

PARTICIPANTS

Patients aged ≥18 years with primary open-angle, primary angle-closure, pseudoexfoliation, or pigment dispersion glaucoma, bilateral visual acuity of ≥20/400, and no concurrent conditions that may affect color vision.

METHODS

A total of 100 patients provided color descriptions of 11 distinct medication bottle caps. Color descriptors were then presented to 3 physicians. Physicians matched each color descriptor to the medication they thought the descriptor was describing.

MAIN OUTCOME MEASURES

Frequency of patient-physician agreement, occurring when all 3 physicians accurately matched the color descriptor to the correct medication. Multivariate regression models evaluated whether patient-physician agreement decreased with degree of better-eye visual field (VF) damage, color descriptor heterogeneity, or color vision deficiency, as determined by the Hardy-Rand-Rittler (HRR) score and Lanthony D15 color confusion index (D15 CCI).

RESULTS

Subjects had a mean age of 69 (±11) years, with VF mean deviation of -4.7 (±6.0) and -10.9 (±8.4) decibels (dB) in the better- and worse-seeing eyes, respectively. Patients produced 102 unique color descriptors to describe the colors of the 11 bottle caps. Among individual patients, the mean number of medications demonstrating agreement was 6.1/11 (55.5%). Agreement was less than 15% for 4 medications (prednisolone acetate [generic], betaxolol HCl [Betoptic; Alcon Laboratories Inc., Fort Worth, TX], brinzolamide/brimonidine [Simbrinza; Alcon Laboratories Inc.], and latanoprost [Xalatan; Pfizer, Inc., New York, NY]). Lower HRR scores and higher D15 CCI (both indicating worse color vision) were associated with greater VF damage (P < 0.001). Extent of color vision deficiency and color descriptor heterogeneity significantly predicted agreement in multivariate models (odds of agreement = 0.90 per 1 point decrement in HRR score, P < 0.001; odds of agreement = 0.30 for medications exhibiting high heterogeneity [≥11 descriptors], P = 0.007).

CONCLUSIONS

Physician understanding of patient medication use based solely on bottle cap color is frequently incorrect, particularly in patients with glaucoma who may have color vision deficiency. Errors based on communication using bottle cap color alone may be common and could lead to confusion and harm.

Screening patients with tuberculosis for diabetes mellitus in Gujarat, India

SETTING

Anklav Tuberculosis Unit, Anand, Gujarat, India.

OBJECTIVE

To determine in a cohort of TB patients 1) the prevalence of diabetes (DM) and impaired fasting glucose (IFG), 2) the time taken for diagnosis, 3) demographic and clinical factors associated with DM and IFG, and 4) the number needed to screen (NNS) for diagnosing new cases of DM and IFG.

DESIGN

Descriptive study. TB patients registered between January and September 2012 were asked whether they had a history of DM. Those with unknown DM were tested for random and fasting blood glucose (FBG). FBG of ≥126 mg/dl and 110-125 mg/dl were considered indicative of DM and IFG, respectively.

RESULTS

Of 556 TB patients, 553 (99%) were assessed: 36 (6.5%) had diabetes (14 had been previously diagnosed DM and 22 were newly diagnosed), and 39 (7%) had IFG. The median (interquartile range) time to DM diagnosis was 5 (1-17) days. Age ≥35 years was associated with DM. The NNS was 25 and 14 for one new case of DM and IFG, respectively, with a lower NNS in males, those aged ≥35 years, those with smear-positive pulmonary TB, retreatment patients and smokers.

CONCLUSION

This pilot project shows that it is feasible and valuable to screen patients with TB for DM in a routine setting, resulting in earlier identification of DM and opportunities for better management of comorbidity.

Tobacco sales and marketing within 100 yards of schools in Ahmedabad City, India

OBJECTIVES

The Government of India passed the Cigarettes and Other Tobacco Products (Prohibition of Advertisement and Regulation of Trade and Commerce, Production, Supply and Distribution) Act, 2003 (COPTA 2003), which prohibits the sale of tobacco products within 100 yards of educational institutions and regulates tobacco advertising. The aim of this research was to monitor compliance with the section of COPTA 2003 regarding the advertisement, display and sale of tobacco products around educational institutions in Ahmedabad City, India.

STUDY DESIGN

Observational study around 30 randomly selected schools.

METHODS

In March 2010, an observational study was conducted to assess compliance with COPTA 2003 in Ahmedabad City, India. All vendors within a 100-yard radius of 30 randomly selected schools were identified. At locations where tobacco was sold, information was collected regarding type of product sold, sale of tobacco in single units and advertising.

RESULTS

Twenty public schools and 10 private schools were sampled. Of these, 87% [n = 26, 95% confidence interval (CI) 69-95%] had tobacco sales within 100 yards of their entrance. Of the 771 vendors observed, 24% (n = 185, 95% CI 18-32%) sold tobacco products. Tobacco advertising in violation of the law was found around 57% of schools (n = 17, 95% CI 39-73%), product displays around 83% of schools (n = 25, 95% CI 65-93%) and single sales around 70% of schools (n = 21, 95% CI 51-84%).

CONCLUSIONS

Violation of the sections of COPTA 2003 regarding sale of tobacco products around educational institutions and advertising in general is widespread in Ahmedabad City, India. Effective enforcement of the existing law is necessary to protect the children in India from widespread exposure to the sale and marketing of tobacco products.

KRAS G>A mutation favors poor tumor differentiation but may not be associated with prognosis in patients with curatively resected duodenal adenocarcinoma

KRAS mutations have been found in duodenal adenocarcinomas and may have prognostic significance. The purpose of this study was to classify clinicopathological characteristics, microsatellite instability and KRAS mutations and identify possible prognostic role of KRAS mutations in duodenal adenocarcinomas. Demographics, tumor characteristics and survival were recorded for 78 patients with duodenal adenocarcinomas (Stages I-III). KRAS mutations were detected in 27 (34.6%) cases, of which the majority (74.1%) were G>A transitions. Multivariate logistic regression analysis showed that KRAS G>A mutation was significantly associated with late stage (p = 0.025) and poor tumor differentiation (p = 0.035), when compared with wild-type and other than G>A mutations. KRAS G>A mutation carriers were at increased risk for distant relapse (p = 0.022) and had significantly shorter overall survival (OS; log-rank p = 0.045) and a trend toward shorter relapse-free survival (RFS; log-rank p = 0.062) when compared with those who did not carry the KRAS G>A mutation. In multivariate analyses, there was a significant correlation between ≥ 3 positive lymph nodes and poor OS (p < 0.001) and RFS (p = 0.001) and KRAS G>A mutation carriers demonstrated no effect on clinical outcome. In conclusion, KRAS G>A mutation correlates significantly with late stage and poor tumor differentiation in duodenal adenocarcinoma. Among patients who undergo a curative resection of duodenal adenocarcinoma, KRAS G>A mutation carriers will more likely experience distant relapse but may not exhibit a poor prognosis. The number of positive lymph nodes should be incorporated in future staging systems.

CpG island methylator phenotype-positive tumors in the absence of MLH1 methylation constitute a distinct subset of duodenal adenocarcinomas and are associated with poor prognosis

PURPOSE

Little information is available on genetic and epigenetic changes in duodenal adenocarcinomas. The purpose was to identify possible subsets of duodenal adenocarcinomas based on microsatellite instability (MSI), DNA methylation, mutations in the KRAS and BRAF genes, clinicopathologic features, and prognosis.

EXPERIMENTAL DESIGN

Demographics, tumor characteristics, and survival were available for 99 duodenal adenocarcinoma patients. Testing for KRAS and BRAF mutations, MSI, MLH1 methylation, and CpG island methylator phenotype (CIMP) status was conducted. A Cox proportional hazard model was built to predict survival.

RESULTS

CIMP(+) was detected in 27 of 99 (27.3%) duodenal adenocarcinomas and was associated with MSI (P = 0.011) and MLH1 methylation (P < 0.001), but not with KRAS mutations (P = 0.114), as compared with CIMP(-) tumors. No BRAF V600E mutation was detected. Among the CIMP(+) tumors, 15 (55.6%) were CIMP(+)/MLH1-unmethylated (MLH1-U). Kaplan-Meier analysis showed that tumors classified by CIMP, CIMP/MLH1 methylation status, or CIMP/MSI status could predict overall survival (OS; P = 0.047, 0.002, and 0.002, respectively), whereas CIMP/MLH1 methylation status could also predict time-to-recurrence (TTR; P = 0.016). In multivariate analysis, CIMP/MLH1 methylation status showed a significant prognostic value in both OS (P < 0.001) and TTR (P = 0.023). Patients with CIMP(+)/MLH1-U tumors had the worst OS and TTR.

CONCLUSIONS

Our results showed existence of CIMP in duodenal adenocarcinomas. The combination of CIMP(+)/MLH1-U seems to be independently associated with poor prognosis in patients with duodenal adenocarcinomas. This study also suggests that BRAF mutations are not involved in duodenal tumorigenesis, MSI, or CIMP development.

Cellulitis on face in a patient with congenital afibrinogenemia

Congenital afibrinogenemia is a rare coagulation disorder, with an estimated prevalence of 1 : 1,000,000, characterized by a complete absence to reduced level of circulating fibrinogen. This article presents a case of congenital afibrinogenemia, which presented as cellulitis on the face.

Management of Combat Related Vascular Injuries in a Zonal Hospital

BACKGROUND

The extremity gunshot wound (GSW) and penetrating splinter injuries from mine blast present a surgical challenge in the treatment of arterial trauma especially at non-vascular surgery centre. Adherence to specific principles of management is required for optimal limb salvage.

METHODS

Fourteen vascular injuries in patients of GSW and mine explosions were managed at a zonal military hospital with successful outcome in two years. The diagnosis of arterial injury was done clinically.

RESULTS

The commonest site of vascular injury was femoral. The methods of choice for repair were autogenous vein interposition or end-to-end anastomosis. All except for two patients retained a functional limb.

CONCLUSION

All surgeons in peripheral hospitals should be trained in vascular injury repair to save life and limb. Our series shows that right timing and prompt treatment of vascular injuries in a peripheral hospital, can give satisfactory results.

Mine Blast Injuries - Our Experience

BACKGROUND

The sudden increase in incidence and magnitude of mine blast injuries prompted us to highlight the problem and its management.

METHODS

The cases of mine blast injuries occurring during mining and demining in a particular geographical area were analysed. Total 27 cases of mine blast injuries occurred during mining or demining operations in a period of 13 months.

RESULTS

Various body regions were involved in the mine blast injuries but the main brunt was borne by feet and legs followed by multiple body regions due to splinters. 14 patients underwent below knee (BK) amputation while 4 patients required through knee (TK) amputations. The effect of blast was so severe that most of the cases required 2 to 5 times wound debridements. The initial aggressive debridement / open stump amputation saved the limb and life of all patients.

CONCLUSION

A mine blast causes extensive injuries and psychological trauma. Management is needed urgently, surgery is difficult, and amputation is often inevitable. Maximum lives and limbs can be saved with aggressive debridement, repeated inspections and dressings under anaesthesia and definitive closure at optimum time.

Lead in paint and soil in Karnataka and Gujarat, India

Blood lead surveys in several areas of India have found very high percentages of children with elevated blood lead levels. Fifty-three percent of children under 12 years of age in a seven-city screening had blood lead levels equal to or greater than 10 microg/dL, the level currently considered elevated by the U.S. Centers for Disease Control and Prevention (CDC). A number of these surveys focused on populations near lead smelters or in areas with high lead levels from combustion of lead-containing gasoline. There is little information available, however, on the levels of lead in paint in India and in soil. Field portable X-ray fluorescence analyzers were used to determine environmental lead levels in paint, dust, air, soil, and other bulk samples near several lead-using industries and in the residential environments of children with very high blood lead levels, at least four times as high as the CDC limit. Soils near industrial operations, such as secondary lead smelters, and battery dismantling units contained levels up to 100,000 ppm of lead. Four of 29 currently available paints from five manufacturers measured 1.0 mg/cm2 or above--the current U.S. definition of lead-based paint in housing-after the application of a single coat; four others measured at least 1.0 after three coats, and three others likely reached this level after the application of an additional one or two coats. In 5 of 10 homes of the elevated blood lead children, three or more locations in or around the home were found to have lead paint levels of 1.0 mg/cm2 or higher. Soil exceeding the U.S. standard for residential areas (400 ppm) was found at only one of the houses. Other sources of lead exposure, including traditional ayurvedic medicine tablets, were also observed. Similar surveys would be useful elsewhere in India and in other developing countries.

Bone marrow examination at a paediatric hospital in Kenya

OBJECTIVE

To investigate the main indications for, and common conditions found in bone marrow examinations (BME) of children.

METHODS

This was a retrospective study from September 1, 1993 to September 3 1998. All bone marrow aspirate and trephine biopsy results were retrieved. The clinical data provided by clinicians were also noted.

RESULTS

A total of 97 BME were recorded from patients aged two months to 13 years. The peak ages for BME were six to eight years (24% of patients). The more frequent indications for BME were unexplained anaemia found in 26% request forms, investigation for solid tumours (10%) and lymphoma (10%) and remission assessment after treatment for leukaemia (26%). The main findings were malignancy (27%) with leukaemia being commonest (ALL) 16% of patients and acute myeloblastic leukaemia (5%). Haematinic deficiency was seen in 12.7% of cases with iron deficiency being the commonest. There were some notable differences and similarities in the study as compared to a similar one performed at a local referral hospital.

CONCLUSION

The importance of BME as a crucial investigational tool in the management of patients is underscored. Interpretation is more meaningful when the haematologist has adequate clinical data.

A study of the therapeutic efficacy of various regimes in chronic urticaria

A total of sixty patients with chronic urticaria (>3 months duration) were divided into three groups. Group A - was treated once daily with tab loratadine 10 mg. Group B- with cetrizine 10 mg and Group C - with tab fexofenadine hydrochloride 180 mg. Total duration of treatment was 4 weeks. Pre and Post treatment evaluation were made. It was observed that loratadine was superior to all, cetrizine was second and fexofenadine was third regarding over all clinical efficacy, while side effects like sedation was maximum observed in nine cases, with cetrizine, No side effects were observed with the other two regimens.

Megaloblastic marrow in macrocytic anaemias at Kenyatta National and M P Shah Hospitals, Nairobi

OBJECTIVE

To determine the diagnostic value of megaloblastic marrow in patients with possible vitamin B12 and/or folate deficiency and to look for criteria that could be used in diagnosis of vitamin B12 deficiency.

DESIGN

Prospective study.

SETTING

Kenyatta National Hospital and M P Shah Hospital, Nairobi.

SUBJECTS

Patients of all age groups and both sexes presenting with clinical and blood picture of macrocytic anaemia.

MAIN OUTCOME MEASURES

Response to vitamin B12 injections. Vitamin B12 deficiency diagnosed by the following methods: Vitamin B12 serum level assays alone, bone marrow examination alone and both vitamin B12 assays and bone marrow examination. Response was measured clinically and by increase in haemoglobin level after three weeks of treatment.

RESULTS

Three hundred and forty-three patients were evaluated; 156 (45.5%) were males, and 187 (54.5%) females. Age range was 13-80 years and a mean of 37.7 years. Initial investigations were as follows: 21.9% had vitamin B12 assays only, 59.2% bone marrow examination only and 19.9% both vitamin B12 assayed and bone marrow evaluated. Haemoglobin increase after a total of 6,000 mcg of vitamin B12 was between 2.6-4.6 g/dl in three weeks. Reticulocytes measured on day ten ranged between 12% and 17%. Uniform improvement in all patients was observed for white blood cells (WBC) and platelet counts. Other significant results and observations included clinical improvement in the signs and symptoms of anaemia after the 6,000 mcg injection of vitamin B12 given over three weeks. Serum folic acid level was determined in 21% of cases and in all these it was normal.

CONCLUSION

The important practical points were response to vitamin B12 in all cases and the importance of re-assessing patients after a total of 6,000 mcg of vitamin B12. Folic acid deficiency was not detected. Patients in these two institutions with megaloblastic anaemia had vitamin B12 deficiency. It is proposed that a model consisting of oval macrocytosis on blood film and megablastic bone marrow be treated with vitamin B12 injections in settings where vitamin B12 serum level assays are not easily available.

Physicochemical consequences of amino acid variations that contribute to fibril formation by immunoglobulin light chains

The most common form of systemic amyloidosis originates from antibody light chains. The large number of amino acid variations that distinguish amyloidogenic from nonamyloidogenic light chain proteins has impeded our understanding of the structural basis of light-chain fibril formation. Moreover, even among the subset of human light chains that are amyloidogenic, many primary structure differences are found. We compared the thermodynamic stabilities of two recombinant kappa4 light-chain variable domains (V(L)s) derived from amyloidogenic light chains with a V(L) from a benign light chain. The amyloidogenic V(L)s were significantly less stable than the benign V(L). Furthermore, only the amyloidogenic V(L)s formed fibrils under native conditions in an in vitro fibril formation assay. We used site-directed mutagenesis to examine the consequences of individual amino acid substitutions found in the amyloidogenic V(L)s on stability and fibril formation capability. Both stabilizing and destabilizing mutations were found; however, only destabilizing mutations induced fibril formation in vitro. We found that fibril formation by the benign V(L) could be induced by low concentrations of a denaturant. This indicates that there are no structural or sequence-specific features of the benign V(L) that are incompatible with fibril formation, other than its greater stability. These studies demonstrate that the V(L) beta-domain structure is vulnerable to destabilizing mutations at a number of sites, including complementarity determining regions (CDRs), and that loss of variable domain stability is a major driving force in fibril formation.

Expression of Saccharomyces cerevisiae MATa and MAT alpha enhances the HO endonuclease-stimulation of chromosomal rearrangements directed by his3 recombinational substrates

Radiation resistance in Saccharomyces cerevisiae is greater in a/alpha diploids than in aa or alpha alpha diploids, and higher levels of radiation resistance correlates with more mitotic recombination. Specifically, we investigated whether the stimulation of directed translocations, inversions, and unequal sister chromatid exchanges (SCEs) by HO endonuclease-induced double-strand breaks (DSBs) is enhanced in a/alpha cells. These rearrangements result from mitotic recombination between two truncated his3 genes, his3-delta 5' and his3-delta 3'::HOcs, positioned on non-homologous chromosomes or positioned in juxtaposition on the same chromosome in inverted or direct orientation. Mitotic recombination was initiated by HO endonuclease-induced DSBs at the HO cut site (HOcs) located at his3-delta 3'::HOcs, and His+ recombinants were selected. In MATa-inc haploid strains, which do not switch mating-type, the DSB reduced viability, relative to undamaged cells, and increases the frequency of His+ recombinants containing translocations to 2.4 x 10(-4) (seven-fold), SCEs to 5.4 x 10(-4) (five-fold), and inversions to 1.8 x 10(-3) (six-fold). Compared to a haploids, DSB-stimulated frequencies in a/alpha haploids were three-fold higher for translocations, two-fold higher for SCEs, and ten-fold higher for inversions; however DSB-induced lethality was greater in a/alpha haploids. Compared to aa diploids, DSB-stimulated frequencies of translocations and viability after chromosome cleavage were greater in a/alpha diploids. We suggest that heterozygosity at MAT may elevate the frequency of DSB-initiated reciprocal exchange events in both haploid and diploid cells, but may only increase viability after chromosome cleavage in diploid cells.

Experiences in paying for health care in India's voluntary sector

This article summarizes the results of four in-depth case studies on the financing and costs of the health care programmes of well-known non-government organizations (NGOs) in India. These organizations have shown a high degree of creativity and innovation in developing varied sources of financing to reduce dependency and enable them to sustain their programmes. Government funds play a major role in supporting these voluntary health activities, with less significant roles played by foreign donations, user charges, pre-paid memberships, and public fund raising. Some effective methods of assuring access for poor clients while developing self financing are described. Cost studies of the NGOs' health schemes indicate that they operate at least as efficiently as public services and primarily supplement rather than substitute for such services. Suggestions for further development of voluntary sector financing are put forward.

Mating type regulates the radiation-associated stimulation of reciprocal translocation events in Saccharomyces cerevisiae

Both ultraviolet (UV) and ionizing radiation were observed to stimulate mitotic, ectopic recombination between his3 recombinational substrates, generating reciprocal translocations in Saccharomyces cerevisiae (yeast). The stimulation was greatest in diploid strains competent for sporulation and depends upon both the ploidy of the strain and heterozygosity at the MATlocus. The difference in levels of stimulation between MATa/MAT alpha diploid and MAT alpha haploid strains increases when cells are exposed to higher levels of UV radiation (sevenfold at 150 J/m2), whereas when cells are exposed to higher levels of ionizing radiation (23.4 krad), only a twofold difference is observed. When the MAT alpha gene was introduced by DNA transformation into a MATa/mat alpha::LEU2+ diploid, the levels of radiation-induced ectopic recombination approach those obtained in a strain that is heterozygous at MAT. Conversely, when the MATa gene was introduced by DNA transformation into a MAT alpha haploid, no enhanced stimulation of ectopic recombination was observed when cells were irradiated with ionizing radiation but a threefold enhancement was observed when cells were irradiated with UV. The increase in radiation-stimulated ectopic recombination resulting from heterozygosity at MAT correlated with greater spontaneous ectopic recombination and higher levels of viability after irradiation. We suggest that MAT functions that have been previously shown to control the level of mitotic, allelic recombination (homolog recombination) also control the level of mitotic, radiation-stimulated ectopic recombination between short dispersed repetitive sequences on non-homologous chromosomes.

DNA-damaging agents stimulate the formation of directed reciprocal translocations in Saccharomyces cerevisiae

DNA-damaging agents can stimulate the formation of directed reciprocal translocations in strains of Saccharomyces cerevisiae containing his3 recombinational substrates to generate chromosomal rearrangements. Such agents were compared with those that can stimulate sister-chromatid recombination. We show that chemicals and environmental agents that produce a variety of DNA lesions, including bulky adduct, thymidine dimers, interstrand cross-links, double-strand breaks alkylated bases, can stimulate recombination to yield reciprocal translocations. Of the agents tested, only the alkylating agents methyl methanesulfonate (MMS) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), and a bifunctional agent that causes bulky DNA adducts, 4-nitroquinoline-N-oxide (4-NQO), significantly stimulate sister-chromatid recombination in our assay. Factors that contribute to the stimulation of interchromosomal recombination include strain genetic background and ploidy.

Significance of pleural effusion in patients with acute pancreatitis

We retrospectively reviewed the charts of all patients with acute pancreatitis admitted to our hospital between July 1987 and June 1991 to determine the relationship of a pleural effusion in patients with acute pancreatitis with the severity of the disease, the etiology of the pancreatitis, pseudocyst formation, and triglyceride levels. Eleven (13.4%) of the 82 patients with acute pancreatitis had evidence of pleural effusion. Eight of 42 patients with alcoholic pancreatitis developed an effusion, compared with one of 33 patients with biliary pancreatitis, indicating that an alcoholic etiology may be a risk factor. Seven (63%) of the 11 patients had associated pseudocysts. Patients with severe disease had a greater incidence of pleural effusion. The effusion was on the left side in six, bilateral in four, and on the right side in one patient. Hypertriglyceridemia did not appear to be an independent risk factor associated with pleural effusions. Diagnostic thoracentesis was performed in three patients because of the presence of fever. Pleural fluid amylase was normal in one case and mildly elevated in the other two. All effusions resolved spontaneously without the need for any therapeutic intervention.

Serum lipase: a better test to diagnose acute alcoholic pancreatitis

OBJECTIVE

To determine whether serum lipase is a better test than serum amylase to diagnose acute alcoholic pancreatitis.

PATIENTS

Two hundred two asymptomatic chronic alcoholics (Group A) and 29 patients with image-proven pancreatitis (Group P).

MEASUREMENTS

Serum lipase was measured using the Kodak Ektachem clinical chemistry slide. Serum amylase was estimated using the Kodak Ektachem clinical chemistry slide or the Beckman Astra amylase chemistry module.

RESULTS

The level of serum amylase in Group A ranged from 17 to 347 U/L (mean 71, SD +/- 36 U/L) and in Group P from 180 to 2,985 U/L (mean 722, SD +/- 663 U/L). Thirteen of 29 patients (45%) with image-proven pancreatitis had levels that overlapped those found in asymptomatic alcoholics. The serum lipase levels in Group A ranged from 34 to 600 U/L (mean 186, SD +/- 111 U/L), while in Group P, the corresponding figures were 1,011 to 25,706 U/L (mean 5,822, SD +/- 5,664 U/L). None of the 29 patients with image-proven pancreatitis had levels that overlapped those found in asymptomatic alcoholics.

CONCLUSIONS

Serum lipase is a better test that serum amylase to diagnose acute alcoholic pancreatitis.

Damage to the plasma membrane in Escherichia coli K-12 induced by far-ultraviolet radiation and its repair

Escherichia coli cells treated with low fluences of far-uv radiation (up to 90 J/m2) showed repairable damage to the plasma membrane. The loss of the ability of the cells to exclude citrate was evident from the respiratory stimulation of irradiated cells when citrate was provided exogenously. This loss of a barrier was a result of a structural disorganization of the plasma membrane as seen by freeze-etching electron microscopy. Analysis of the plasma membrane proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed a characteristic loss of certain membrane proteins. When irradiated cells were incubated in glucose minimal medium at 37 degrees C for various times, a gradual recovery of membrane structure and function was observed. The recovery process was inhibited in the absence of an energy source as well as protein synthesis. The majority of the recovery occurred in the initial 1 h of the postirradiation holding. These results demonstrated that far-uv radiation at a fluence less than the D10 value had a direct or indirect effect on plasma membrane proteins, causing their release from the membrane bilayer. The lost proteins were subsequently regained by de novo protein synthesis.

Serum lipase levels in chronic alcoholics

Using an elevated serum amylase level to diagnose acute pancreatitis in an alcoholic patient with abdominal pain may not be appropriate, because hyperamylesemia is common in asymptomatic alcoholics without acute pancreatitis. To determine whether serum lipase also suffers from the same drawback, we undertook a prospective study involving 202 asymptomatic alcoholics admitted to the detoxification unit of our hospital. Sixty-six of the 202 patients had serum lipase levels above the normal range (0-213 U/L). Of these 66, 55 (83%) had levels that were one to two times normal, while 11 patients had levels ranging between two and three times normal. No patient exceeded three times the normal level. This background information is important in the interpretation of serum lipase levels in alcoholic patients with abdominal pain.

Influence of far-ultraviolet radiation on the permeability of the outer membrane of Escherichia coli

Far-ultraviolet radiation (254 nm) at a dose of 10, 20, and 30 J/m2 was found to disrupt the outer membrane permeability barrier of Escherichia coli to various antibiotics, dyes, and detergents. The degree of sensitization to these agents was proportional to the radiation dose. The irradiated cells showed a significant increase in the sensitivity of hydrophilic antibiotics (ampicillin, carbenicillin, penicillin), whereas much less sensitization was found towards hydrophobic probes (kanamycin, erythromycin, rifamycin SV, crystal violet, phenol, novobiocin) and detergents (dodecyl sulfate, bile salt, Triton X-100). The biochemical data and ultrastructural analysis of the outer membrane by freeze-etching have shown that the increase in phospholipid:protein ratio after irradiation had changed the architecture of the outer membrane from a highly asymmetric bilayer structure with densely packed lipopolysaccharide--protein particles on the outer half, to one predominantly exhibiting smooth phospholipid bilayer characteristics. The structure, composition, and barrier function of the outer membrane were restored to normal within 3 h of postirradiation incubation in nonproliferative medium. During this period, the acquisition of resistance towards a hydrophilic antibiotic (ampicillin) was faster than that for a hydrophobic agent (phenol).

Cerebellar hemorrhage complicating methylmalonic and propionic acidemia

Methylmalonic (MMA) and propionic (PPA) acidemias are inherited disorders characterized by a wide spectrum of clinical and biochemical findings. We report the neuropathologic findings in two young infants with MMA and PPA in which death probably resulted from cerebellar hemorrhage. When combined with a previous report of isovaleric acidemia complicated by diffuse subarachnoid and parenchymal cerebellar hemorrhage, it is apparent that cerebellar hemorrhage must be considered in any infant with a fulminating organic acidemia. Rapid neurologic deterioration despite an improvement in acidosis and hyperammonemia is an indication for computed tomography of brain. Surgical evacuation of the blood may improve the chance for survival in this catastrophic illness.

Fatal hemorrhage from rectal varices. Report of two cases

We report two cirrhotic patients who succumbed to massive rectal bleeding. The source of this hemorrhage remained undiscovered clinically despite endoscopy, a bleeding scan, and celiac angiogram in one patient. Autopsy revealed that the source of the bleeding was rectal varices in both cases.