Timing and causes of forest fire at the K-Pg boundary.

We report K-Pg-age deposits in Baja California, Mexico, consisting of terrestrial and shallow-marine materials re-sedimented onto the continental slope, including corals, gastropods, bivalves, shocked quartz grains, an andesitic tuff with a SHRIMP U-Pb age (66.12 ± 0.65 Ma) indistinguishable from that of the K-Pg boundary, and charred tree trunks. The overlying mudstones show an iridium anomaly and fungal and fern spores spikes. We interpret these heterogeneous deposits as a direct result of the Chicxulub impact and a mega-tsunami in response to seismically-induced landsliding. The tsunami backwash carried the megaflora offshore in high-density flows, remobilizing shallow-marine fauna and sediment en route. Charring of the trees at temperatures up to > 1000 °C took place in the interval between impact and arrival of the tsunami, which on the basis of seismic velocities and historic analogues amounted to only tens of minutes at most. This constrains the timing and causes of fires and the minimum distance from the impact site over which fires may be ignited.

Asphaltene detection using surface enhanced Raman scattering (SERS).

Surface enhanced Raman spectroscopy using a gold substrate and excitation at 514 nm can detect sub parts per million quantities of asphaltene and thereby petroleum. This simple format and sensitivity make it transformative for applications including sample triage, flow assurance, environmental protection and analysis of unique one of a kind materials.

Liquid vs. solid culture for tuberculosis: performance and cost in a resource-constrained setting.

SETTING: National Health Laboratory Services tuberculosis (TB) laboratory, South Africa. OBJECTIVES: To compare Mycobacterium Growth Indicator Tube (MGIT) with Löwenstein-Jensen (LJ) medium with regard to Mycobacterium tuberculosis yield, time to positive culture and contamination, and to assess MGIT cost-effectiveness. DESIGN: Sputum from gold miners was cultured on MGIT and LJ. We estimated cost per culture, and, for smear-negative samples, incremental cost per additional M. tuberculosis gained with MGIT using a decision-tree model. RESULTS: Among 1267 specimens, MGIT vs. LJ gave a higher yield of mycobacteria (29.7% vs. 22.8%), higher contamination (16.7% vs. 9.3%) and shorter time to positive culture (median 14 vs. 25 days for smear-negative specimens). Among smear-negative samples that were culture-positive on MGIT but negative/contaminated on LJ, 77.3% were non-tuberculous mycobacteria (NTM). Cost per culture on LJ, MGIT and MGIT+LJ was respectively US$12.35, US$16.62 and US$19.29. The incremental cost per additional M. tuberculosis identified by standard biochemical tests and microscopic cording was respectively US$504.08 and US$328.10 using MGIT vs. LJ, or US$160.80 and US$$109.07 using MGIT+LJ vs. LJ alone. CONCLUSION: MGIT gives higher yield and faster results at relatively high cost. The high proportion of NTM underscores the need for rapid speciation tests. Minimising contaminated cultures is key to cost-effectiveness.

Correlation of clinicopathological features with immunohistochemical expression of cell cycle regulatory proteins p16 and retinoblastoma: distinct association with keratinisation and differentiation in oral cavity squamous cell carcinoma.

BACKGROUND: The p16 and retinoblastoma (Rb) gene products are part of the retinoblastoma pathway controlling the G1-S transition of the cell cycle. Few studies on the expression of p16 and retinoblastoma proteins in oral cavity squamous carcinomas have been conducted. AIM: To correlate the expression of p16 and retinoblastoma proteins to clinicopathological characteristics in these tumours. METHODS: 45 patients with resected oral cavity squamous carcinoma were selected, for whom this was the initial treatment and who were followed up for 5 years or until death. Immunohistochemical stains with antibodies to the Rb and p16 gene products were carried out on paraffin wax-embedded tissue. Data on clinicopathological features such as tumour differentiation, nodal status, stage and survival outcome were collected. RESULTS: Retinoblastoma expression was seen in 39 of 45 (87%) patients and p16 expression in 6 of 45 (13%) patients. A significant inverse correlation was observed between retinoblastoma and p16 expression as nearly all retinoblastoma negative cases were p16 positive, and vice versa. When examined for clinicopathological correlates, it was found that all 39 tumours that expressed retinoblastoma displayed marked keratinisation and were of low-moderate histological grade. Conversely, five of the six tumours that expressed p16 were found to be poorly differentiated, with minimal keratin expression. CONCLUSIONS: Salient relationships were seen between expression of retinoblastoma and p16 and keratinisation. A marked loss of keratin production was evident in the tumours that expressed p16. Tumours expressing retinoblastoma were seen to exhibit more widespread keratinisation. In addition, an inverse staining pattern was found for retinoblastoma and p16 as retinoblastoma-expressing tumours were nearly universally p16 negative and vice versa. No correlation of expression of either p16 or retinoblastoma was found with survival or stage. A link between the histologically observable morphology and expression of cell cycle regulatory protein with the expression of p16 and retinoblastoma has been suggested with keratinisation and differentiation of status.

Women's experiences of and preferences for services after rape in South Africa: interview study.

OBJECTIVES: To describe aspects of delivery of health services after rape, including trade-offs, that would most influence choice of service, and to compare views of patients who had used such services with views of members of the community who may be future users or may have experienced barriers to service use. DESIGN: Discrete choice analysis of stated preferences with interviews. Attributes included travel time to the service, availability of HIV prophylaxis, number of returns to the hospital, medical examination, and counselling skills and attitude of the provider. SETTING: One rural and one urban site in South Africa. PARTICIPANTS: 319 women: 155 who had been raped and four carers recruited through health facilities and 160 comparable women recruited from the community. Of these, 156 were from an urban site and 163 from a rural site. MAIN OUTCOME MEASURES: Strength of preferences over a range of attributes through the estimation of a benefit function through random effects probit modelling. RESULTS: Factors such as the availability of prophylactic treatment for HIV infection and having a sensitive healthcare provider who could provide counselling are more important in women's decisions to seek care after rape than the travel time necessary to access those services. CONCLUSION: Our findings support the need for holistic rape services.

Characterization of freshwater natural aquatic colloids by atomic force microscopy (AFM).

Atomic force microscopy (AFM) has been used to image and quantify riverine colloids in a quantitative and relatively nonperturbing manner. Three main classes of material have been imaged including fibrils (about 10 nm in diameter and 100 nm or more in length), discrete, near-spherical, small colloids primarily below 30-50 nm in diameter, and a surface film, of at least several nanometers thickness, which coatsthe entire mica surface within 30 min of exposure to river water. Colloid structure was found to vary as a function of pH, particularly at high pH. Substantially different structures were observed at high pH values, with the loss of the near-spherical colloids possibly due to rearrangement and aggregation. In addition,film thicknesses of up to 100 nm were estimated on the silicon nitride AFM cantilever after 30 h of deposition in the same water (unperturbed and size fractionated). The observation of these surface films has important implications for understanding the mechanisms by which colloids might bind trace elements. In particular, development of surface coatings implies that binding of pollutants (at least initial surface binding) may be dominated by adsorbed surface layers.

The epidemiology and cost of trauma to the orthopaedic department at a secondary-level hospital

Trauma in South Africa is indeed a 'malignant epidemic'. Approximately 70 000 South Africans die every year; and a further 3.5 million seek care at health care facilities; as a result of trauma. From 1990 to 2020 there is likely to be a significant increase in the injury-related burden of disease in sub-Saharan Africa unless effective prevention measures are put in place. Approximately 9 000 people are killed on South Africa's roads every year; and 33 000 seriously injured. Our road traffic death rate of 11.7 per 100 million kilometres travelled ranks in the top 10 in the world. Nationally; 39of those killed on the road are pedestrians; although this figure has decreased from 47in 1987. This study attempted to outline the epidemiological pattern of trauma and the costs of this trauma over a year in the orthopaedic department at a single secondary-level urban hospital in Durban. For the purposes of this study; trauma was defined as injury arising from assault; gunshot or motor vehicle accidents (MVAs)

The epidemiology and cost of trauma to the orthopaedic department at a secondary-level hospital : trauma

Trauma in South Africa is indeed a 'malignant epidemic'. Approximately 70 000 South Africans die every year; and a further 3.5 million seek care at health care facilities; as a result of trauma. From 1990 to 2020 there is likely to be a significant increase in the injury-related burden of disease in sub-Saharan Africa unless effective prevention measures are put in place. Approximately 9 000 people are killed on South Africa's roads every year; and 33 000 seriously injured. Our road traffic death rate of 11.7 per 100 million kilometres travelled ranks in the top 10 in the world. Nationally; 39of those killed on the road are pedestrians; although this figure has decreased from 47 in 1987. This study attempted to outline the epidemiological pattern of trauma and the costs of this trauma over a year in the orthopaedic department at a single secondary-level urban hospital in Durban. For the purposes of this study; trauma was defined as injury arising from assault; gunshot or motor vehicle accidents (MVAs)

Clinical course correlates poorly with muscle pathology in nemaline myopathy.

OBJECTIVE: To report pathologic findings in 124 Australian and North American cases of primary nemaline myopathy. METHODS: Results of 164 muscle biopsies from 124 Australian and North American patients with primary nemaline myopathy were reviewed, including biopsies from 19 patients with nemaline myopathy due to alpha-actin (ACTA1) mutations and three with mutations in alpha-tropomyosin(SLOW) (TPM3). For each biopsy rod number per fiber, percentage of fibers with rods, fiber-type distribution of rods, and presence or absence of intranuclear rods were documented. RESULTS: Rods were present in all skeletal muscles and diagnosis was possible at all ages. Most biopsies contained nemaline bodies in more than 50% of fibers, although rods were seen only on electron microscopy in 10 patients. Rod numbers and localization correlated poorly with clinical severity. Frequent findings included internal nuclei and increased fiber size variation, type 1 fiber predominance and atrophy, and altered expression of fiber type specific proteins. Marked sarcomeric disruption, increased glycogen deposition, and intranuclear rods were associated with more severe clinical phenotypes. Serial biopsies showed progressive fiber size variation and increasing numbers of rods with time. Pathologic findings varied widely in families with multiple affected members. CONCLUSIONS: Very numerous nemaline bodies, glycogen accumulation, and marked sarcomeric disruption were common in nemaline myopathy associated with mutations in skeletal alpha-actin. Nemaline myopathy due to mutations in alpha-tropomyosin(SLOW) was characterized by preferential rod formation in, and atrophy of, type 1 fibers. Light microscopic features of nemaline myopathy correlate poorly with disease course. Electron microscopy may correlate better with disease severity and genotype.

Geographic patterns of deprivation in South Africa: informing health equity analyses and public resource allocation strategies

Provides some insights into how to strengthen resource allocation in pursuit of vertical equity goals within South Africa. The resource allocation implications of this study have particular relevance to countries that have pursued a devolution approach to decentralization. Document in PDF format, required Acrobat Reader.

Geographic patterns of deprivation in South Africa: informing health equity analyses and public resource allocation strategies.

There is a growing interest in the use of small area analyses in investigating the relationship between socioeconomic status and health, and in informing resource allocation decision-making. However, few such studies have been undertaken in low- and middle-income countries (LMICs). This paper reports on such a study undertaken in South Africa. It both looked at the feasibility of developing a broad-based area deprivation index in a data scarce context and considered the implications of such an index for geographic resource allocations. Despite certain data problems, it was possible to construct and compare three different indices: a general index of deprivation (GID), compiled from census data using principal component analysis; a policy-perspective index of deprivation (PID), based on groups identified as priorities within policy documents; and a single indicator of deprivation (SID), selected for relevance and feasibility of use. The findings demonstrate clearly that in South Africa deprivation is multi-faceted, is concentrated in specific areas within the country and is correlated with ill-health. However, the formula currently used by the National Treasury to allocate resources between geographic areas, biases these allocations towards less deprived areas within the country. The inclusion of the GID within this formula would dramatically alter allocations towards those areas suffering from human development deficits. The area in which analysis was undertaken was not, however, sufficiently small to identify pockets of deprivation within the less deprived metropolitan areas. These findings suggest that it is feasible to conduct small area analyses in LMICs but that specific attention needs to be given to the size of the geographic unit used in analysis. In addition, they highlight the importance of considering deprivation in resource allocation mechanisms if vertical equity goals are to be promoted through resource allocation, particularly within decentralized health systems.

Ultrastructural observations on the platelets of the Arabian tahr (Hemitragus jayakari).

The ultrastructure of platelets was studied in specimens of peripheral blood from 18 healthy adult Arabian tahrs (Hemitragus jayakari). The platelets were characterized by their extreme polymorphism. The number of alpha granules, typically one to six per cell, was considerably less than that reported for most animal platelets. Similar to humans, the platelets of the Arabian tahr had nucleoids within the alpha granules. However, nucleoids were not a consistent finding. One or more electron-dense granules, most commonly contained within clear vesicles, was commonly observed. A unique feature was the lack of an open canalicular system, which is considered a hallmark feature of this cell type in most mammalian and reptilian platelets.

Ultrastructural changes in caprine lungs infected with Mycoplasma capricolum subspecies capripneumonia.

Ultrastructural examination of the lungs from goats with natural infections with Mycoplasma capricolum subspecies capripneumonia, the causative agent of contagious caprine pleuropneumonia, revealed extensive hyperplasia of type II pneumocytes. Typically, these type II cells contained abundant numbers of osmiophilic lamellar bodies that had lost most of their characteristic lamellar ultrastructure. These findings were absent in healthy control goats.

Frictional amyloidosis: a study of 10 cases.

Ten patients with macular amyloidosis were studied with particular reference to the role of friction. All 10 patients had a history of prolonged rubbing over a period of 2-5 years with various objects, such as bath sponges, brushes, towels, plant sticks and leaves. The presence of amyloid was confirmed by histochemical stains in six cases and by electron microscopy in four cases. The study confirms the role of friction in the causation of macular amyloidosis and hence, the term 'frictional amyloidosis' aptly describes the condition. The study also emphasizes the need for electron microscopy in the diagnosis of frictional amyloidosis.

Acute myelomonocytic leukaemia with pseudo-Chediak-Higashi inclusions in leukaemic blasts report of an unusual case.

Giant inclusions in the blast cells resembling that of Chediak-Higashi syndrome have been reported only in a handful of cases with acute leukaemia. There is a paucity of data on the ultrastructural appearance of such unique light microscopic findings. As many of such patients were reported in late seventies and early eighties [1-4] the outcome of treatment using present day multiple induction/consolidation regimens in such patients has also been rarely reported due to the rarity of such patients. We report here on a patient with acute myeloid leukaemia showing pseudo-Chediak-Higashi inclusions in leukaemic blasts with unusual ultrastructural morphology.

Intense eosinophilia with abnormal ultrastructure as presenting manifestation of acute lymphoblastic leukemia.

A patient with acute lymphoblastic leukemia presented with intense eosinophilia. Under the light microscope these eosinophils showed smaller eosinophilic granules and were detected as neutrophils by Coulter Gen-S cell counter. This counter identifies cell morphology by size and forward and right angle light scatter of cells. Under electron microscopy these eosinophils had smaller and fewer granules and very few crystalloid structures, thereby explaining the inability of the cell counter to identify them as eosinophils. Eosinophilia subsided at 6 months of treatment, i.e. 5 months after the patient went into morphological remission; cytogenetic and bone marrow analyses revealed no abnormality.

An abattoir survey of caprine liver diseases in the sultanate of Oman.

The examination of 675 caprine livers from a slaughterhouse in the Greater Muscat area in the Sultanate of Oman revealed that 63 (9.3%) exhibited gross pathological changes leading to condemnation of this organ. Forty of these livers (71.4%) exhibited one major abnormality, whereas the remaining 28.6% had two or more lesions. The most frequently occurring disorder was diffuse hepatic lipidosis (4.0%), followed by bacterial associated abscesses (2.4%), cysticercosis (1.9%), and eosinophilic granulomata (1%). Although the cause for the hepatic lipidosis was not determined it appeared to be a reversible condition based on the absence of degenerative nuclei within the affected hepatocytes. Conditions observed in only a single liver were subcapsular (non-parasitic) cysts, focal necrosis, micronodular cirrhosis, extensive bile duct proliferation and diffuse haemorrhage.

Atypical outbreak of caprine cryptosporidiosis in the Sultanate of Oman.

An outbreak of cryptosporidiosis occurred in goats ranging in age from two days to adult, on a well-managed closed farm. None of the other animals on the farm, including sheep, cows and buffalo, were affected. Morbidity approached 100 per cent in goats less than six months of age. Despite intensive supportive care, 238 goats died, ranging in age from two days to over one year. Cryptosporidia were detected in large numbers in the intestinal contents of dead animals and in faecal smears of animals with diarrhoea. Massive numbers of the organisms were also demonstrated histopathologically and by electronmicroscopy, and no other significant pathogens were detected. The outbreak was unique in terms of the extreme virulence of the organism, its apparent species-specificity, and the shedding of the organism by animals over four weeks of age.