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S J Connor

Publications and source records attributed to S J Connor.

11 recordsLinked to original sources
PubMed1998

Appendiceal tumors: retrospective clinicopathologic analysis of appendiceal tumors from 7,970 appendectomies.

BACKGROUND: Appendiceal tumors are rare and often unexpectedly discovered in an acute situation, in which decision-making is difficult. To help define the most appropriate management, a retrospective analysis was undertaken to describe the clinicopathologic behavior of appendiceal tumors, and the literature was reviewed of the management of the different types of appendiceal tumors. METHOD: From a single center, a histopathologic database of 7,970 appendectomies, all appendiceal tumors, were identified and case notes reviewed. Analysis of clinical presentation, histopathology, operation, and outcome is presented. RESULTS: During a 16-year period (7,970 appendectomies), 74 patients (0.9 percent) with appendiceal tumors were identified: 42 carcinoid, 12 benign, and 20 malignant. Acute appendicitis was the most common presentation (49 percent), and 9.5 percent were incidental findings. Primary malignant tumors of the appendix were found in 0.1 percent of all appendectomies. Secondary malignant disease was identified in the appendix of 11 patients, most commonly (55 percent) from patients with primary colorectal disease. There was a high incidence of synchronous and metachronous colorectal cancer in all appendiceal tumors: carcinoids, 10 percent; benign tumors, 33 percent; secondary malignancies, 55 percent; primary malignancies, 89 percent. CONCLUSION: Appendiceal tumors are uncommon and most often present as appendicitis. Most are benign and can be managed by appendectomy, except adenocarcinomas and carcinoids larger than 2 cm, which are most appropriately managed by right hemicolectomy. A suggested management algorithm is provided. Controversy exists over the management of carcinoids 1 to 2 cm in size and adenocarcinoids. All types of appendiceal tumors have a high incidence of synchronous and metachronous colorectal cancer.

Adenocarcinoma↗
PubMed1998

Environmental information systems in malaria risk mapping and epidemic forecasting.

Every year between one and two million African children under five die of malaria. If one adds to this the contribution of malaria to all-cause infant mortality then clearly the burden of the disease is catastrophic--a disaster quietly happening each and every year. New tools are needed urgently to support those currently available for control of the disease. An effective vaccine remains elusive. This article outlines the potential contribution to malaria control services of satellite information, which is being used by resource managers in other sectors. In particular, it highlights the lessons which can be learned from early warning systems in other areas, especially those designed to respond to famine. An appendix provides a brief introduction to satellite data and their interpretation.

Africa South of the Sahara↗
PubMed1996

The ecology of malaria--as seen from Earth-observation satellites.

Data from sensors on board geostationary and polar-orbiting, meteorological satellites (Meteosat and NOAA series) are routinely obtained free, via local reception systems, in an increasing number of African countries. Data collected by these satellites are processed to produce proxy ecological variables which have been extensively investigated for monitoring changes in the distribution and condition of different natural resources, including rainfall and vegetation state. How these data products (once incorporated, along with other data, into a geographical information system) could contribute to the goals of monitoring patterns of malaria transmission, predicting epidemics and planning control strategies is the subject of the present review. By way of illustration, an analysis of two of these products, normalized difference vegetation index (NVDI) and cold-cloud duration (CCD), is given in conjunction with epidemiological and entomological data from The Gambia, a country where extensive studies on malaria transmission have been undertaken in recent years. Preliminary results indicate that even simple analysis of proxy ecological variables derived from satellite data can indicate variation in environmental factors affecting malaria-transmission indices. However, it is important to note that the associations observed will vary depending on the local ecology, season and species of vector. Whilst further quantitative research is required to validate the relationship between satellite-data products and malaria-transmission indices, this approach offers a means by which detailed knowledge of the underlying spatial and temporal variation in the environment can be incorporated into a decision-support system for malaria control.

Africa↗
PubMed1995

Entomological evaluation of the Gambia's National Impregnated Bednet Programme.

Entomological studies were conducted in paired study villages in three of the five study areas used for the epidemiological assessment of the Gambia's National Impregnated Bednet Programme. Baseline data collected in 1991 were compared with post-intervention data from 1992, when one of each village pair (from areas II, III and V) was included in the treatment programme in which villagers' nets were dipped in permethrin. In a longitudinal study, indoor-resting densities of Anopheles gambiae s.l. in the treated villages were significantly reduced, when compared with their paired untreated village, in areas II (t = 3.32, 13 degrees of freedom, P = 0.006) and III (t = 3.71, 13 degrees of freedom, P = 0.003). However, this was not associated with higher outdoor-biting rates in the evenings in the treated villages than in the controls. The reduction in vector population was most evident in area II, where the treated village was relatively isolated and 74% of the population slept under a treated net. Anopheles gambiae s.l. were also collected during two fortnightly periods in area V, where the sporozoite rates in 1991 had been relatively high (7.65% and 6.07%). There was no significant decrease in the sporozoite rate in the treated village in area V in 1992, despite the fact that this village was over 5 km from its nearest neighbouring village. However, the proportion of villagers sleeping under a treated net in this village was < 50%. No clear evidence for an epidemiologically significant 'mass killing effect', resulting from the village-wide use of treated nets, emerges in this or any other study undertaken in The Gambia. However, such an effect is indicated by results from Salikene, where the village mosquito population was relatively isolated and where the majority of the population slept under a treated net. This situation is unlikely to be repeated in most Gambian villages in the primary-health-care scheme, since treated and untreated villages are generally interspersed and the mosquito populations move freely between them. We must therefore conclude that, on a national scale, the nets provide an exceptionally high level of personal rather than community protection. The mechanisms underlying the personal protection are, however, still unclear.

Animals↗
PubMed1995

Movement of Anopheles gambiae s.l. malaria vectors between villages in The Gambia.

Movement of mosquitoes belonging to the Anopheles gambiae complex (mixed wild populations of An.arabiensis, An.gambiae and An.melas) between three neighbouring rural villages in The Gambia was investigated by mark-release-recapture. A total of 12,872 mosquitoes were collected in bednets, marked with a magenta fluorescent powder and released over a 15-day period in one of the villages. A further 15,507 mosquitoes were collected in exit traps, marked with a yellow powder and released over the same period. Mosquitoes were captured daily in all three villages using pyrethrum spray catches, as well as bednet and exit trap catches. The catching period extended for 6 days after the last day of release. Of the mosquitoes released, 372 (1.3%) were recaptured 2-21 days later. Of these recaptures, 272 were caught in the release village, and 98 were caught in other villages situated 1-1.4 km away. The 'movement index' between villages was calculated as 17.2% (12.2-22.4% confidence limits) for mosquitoes released after feeding and 20.1% (14.7-25.3%) for those released unfed. These results suggest that movement of mosquitoes between neighbouring villages in The Gambia seriously affects the entomological evaluation of pyrethroid-impregnated bednet programmes in areas where treated and untreated villages are interspersed.

Animals↗
PubMed1993

Vasodilating effect of dipyridamole on rat endoneurial vessels: morphometric study.

Ischaemia plays an important role in the pathogenetic mechanism of various neuropathies. To study the possible vasodilating effects of dipyridamole on peripheral nerve vessels, morphometric analysis of endoneurial vessels was undertaken in rat sciatic and tibial nerves after chronic dipyridamole treatment. Each rat was injected with 4 mg/kg of dipyridamole intraperitoneally twice daily for 5 days/week and once daily during the weekend for a period of 6 weeks. The mean luminal area and perimeter of endoneurial vessels in the sciatic nerve were significantly greater in dipyridamole-treated animals than in controls. The total fascicular area and densities of endoneurial vessels were not significantly different between experimental and control groups. This study demonstrated that daily administration of dipyridamole over a 6 week period caused endoneurial vessels to dilate resulting in increased luminal area and perimeter. Dipyridamole might be a potent therapeutic agent for peripheral neuropathies attributed to nerve ischaemia.

Animals↗
PubMed1992

In vitro hydrogen production by enteric bacteria cultured from children with small bowel bacterial overgrowth.

Lactulose breath hydrogen test and Enterotest string test were carried out simultaneously on 19 children 3-5 years old. Bacteria isolated from the jejunal fluid in upper small intestines of these children were incubated with lactulose at neutral pH. Anaerobes were present in all but one child, and in 15 children they were present in numbers greater than 5 log10 organisms per ml. Most of these bacteria did not produce hydrogen in vitro. Hydrogen production (greater than 100 ppm) was observed with the following bacteria: Bacteroides (5%), clostridia (8%), anaerobic corynebacteria (5%), Escherichia coli (67%), Lactobacillus (8%), Staphylococcus (8%), and Streptococcus (9%). The following bacteria did not produce hydrogen in vitro: Actinobacter, Actinomyces, anaerobic cocci, Bifidobacterium, Fusobacterium, micrococci, Neisseria, Sarcina, and Veillonella. This study suggests that in the diagnosis of small bowel bacterial overgrowth using lactulose breath hydrogen test, it is important to consider that patients with a flat breath hydrogen response to a carbohydrate challenge during the first 60 min may be infected with enteric bacteria which are not capable of producing H2.

Bacteria↗
PubMedDate not supplied

Malaria prevalence is inversely related to vector density in The Gambia, West Africa.

Baseline epidemiological and entomological studies were conducted in 5 different areas of The Gambia before the introduction of a national malaria control programme, the objective of which was to treat all the bed nets belonging to people living in primary health care villages with insecticide. All malariometric indices used (parasite density, parasite rates, splenomegaly, and packed cell volume) indicated that malaria transmission was more intense in the east of the country than elsewhere. High transmission in the east was associated with a high sporozoite rate but not with the greatest vector abundance; the lowest malaria prevalence rates were found in villages which were close to very productive breeding sites of Anopheles gambiae s.l. Bed net usage was strongly correlated with vector density and the highest malaria rates were found in villages where bed net usage was relatively low. These results suggest that in The Gambia malaria prevalence rates are reduced where nuisance biting by mosquitoes is sufficient to encourage the population to protect themselves with bed nets.

Animals↗