蚊虫的共生菌及其在媒介控制中的应用

许多昆虫与寄生在昆虫体表或肠道细胞中的微生物建立了共生关系。臭虫、蚜虫、猎蝽等昆虫可以依靠非最佳食物为生，这一是由于其特殊的生存环境，还由于其体内的共生微生物可以帮助合成和补充其食物中所缺乏的必需营养物质。蚊虫也与其肠道中共生细菌有着密切的联系。成蚊喜产卵于富舍细菌的水体中，水体细菌成为蚊虫幼虫的重要食物来源。伊蚊和库蚊幼虫正常生长发育不可缺少细菌，在无菌条件下饲养，蚊虫或其他媒介昆虫不能正常发育至成熟或不能传播人畜疾病。该文对蚊虫与细菌的共生现象以及其在以下几方面的应用进行综述，（1）蚊虫共生细菌的分离与鉴定，（2）共生细菌的形成与传代，（3）共生细菌在昆虫中的分布，并讨论了经过遗传改造的蚊虫共生细菌对蚊虫防治及控制疟疾等由昆虫传播的疾病的应用前景。     

Information technology infusion model for health sector in a developing country: Nigeria as a case.

To date, information technology (IT) has not been widely adopted in the health sector in the developing countries. Information Technology may bring an improvement on health care delivery systems. It is one of the prime movers of globalization. Information technology infusion is the degree to which a different information technology tools are integrated into organizational activities. This study aimed to know the degree and the extent of incorporation of Information Technology in the Nigerian health sector and derive an IT infusion models for popular IT indicators that are in use in Nigeria (Personal computers, Mobile phones, and the Internet) and subsequently investigates their impacts on the health care delivery system in Nigerian teaching hospitals. In this study, data were collected through the use of questionnaires. Also, oral interviews were conducted and subsequently, the data gathered were analyzed. The results of the analysis revealed that out of the three IT indicators considered, mobile phones are spreading fastest. It also revealed that computers and mobile phones are in use in all the teaching hospitals. Finally in this research, IT infusion models were developed for health sector in Nigeria from the data gathered through the questionnaire and oral interview.     

Fibre optic confocal imaging (FOCI) of keratinocytes, blood vessels and nerves in hairless mouse skin in vivo

Fibre optic confocal imaging (FOCI) enabled subsurface fluorescence microscopy of the skin of hairless mice in vivo. Application of acridine orange enabled imaging of the layers of the epidermis. The corneocytes of the stratum corneum, the keratinocytes in the basal layers and redundant hair follicles were visualised at depths greater than 100 μm. Cellular and nuclear membranes of keratinocytes of the skin were visualised by the use of acridine orange and DIOC5(3). Imaging of the skin after injection of FITC-dextran revealed an extensive network of blood vessels with a size range up to 20 μm. Blood cells could be seen moving through dermal vessels and the blood circulation through the dermal vascular bed was video-taped. The fluorescent dye 4-di-2-ASP showed the presence of nerves fibres around the hair follicles and subsurface blood vessels. Comparison was made between images obtained in vivo using FOCI and in vitro scanning electron microscopy and conventional histology. FOCI offers the potential to study dynamic events in vivo, such as blood flow, skin growth, nerve regeneration and many pathological processes, in ways which have not previously been possible.     

Coaggregation of black-pigmented Bacteroides species with other oral bacteria

Coaggregation of Bacteroides gingivalis and other black-pigmented bacteroides with several oral bacteria was studied with "reagent" strains specially prepared by methods that have been described previously. B. gingivalis coaggregated with Veillonella, Capnocytophaga and Actinomyces spp., but not with any Streptococcus spp. Coaggregation of B. gingivalis with other bacteria was inhibited and reversed by lactose. Of the asaccharolytic black-pigmented bacteroides, only B. gingivalis demonstrated any coaggregation with other bacteria, whereas within the saccharolytic species, B. loescheii showed a marked ability to coaggregate with several species of oral bacteria. This property of coaggregation by B. gingivalis may be an important factor in the pathogenesis of periodontal infections.     

An analysis of hospital-acquired bacteraemia in intensive care unit patients in a university hospital in Kuwait.

An analysis of hospital-acquired bacteraemia among ICU patients was carried out over a two-year period in order to determine the incidence, associated mortality rate and susceptibility pattern of causative pathogens. There was a high incidence of bacteraemia, occurring in 127 (18.4%) of 692 patients. Mortality attributable to nosocomial bacteraemia was 52% of the total 79 deaths from all causes. The highest mortality rate (58.5%) occurred in patients with fungal infections, whilst death from Gram-negative bacteraemia was only 17%. Over 98% of patients had underlying disease. Nearly half (46.8%) of 267 organisms isolated were Gram-positive. In comparison, Gram-negative bacteria accounted for 36.6% and the rest (17.6%) were fungi (mainly Candida albicans). The majority of the bactereamic episodes were monomicrobial (90.2%). Coagulase-negative staphylococci (CNS) were the commonest pathogens isolated, representing 32.6% of all organisms. Inducible beta-lactamase producing organism (Enterobacter spp. 9.7%, Serratia marcescens 6.7%, Klebsiella pneumoniae 6% and Pseudomonas aeruginosa 6%) formed the bulk of Gram-negative bacteria. In contrast, Escherichia coli (7.5%) and K. pneumoniae (4%) were the commonest Gram-negative bacteria from hospital-acquired bacteraemia in the general hospital population. The majority (80%) of CNS were resistant to methicillin (MRSE) but susceptible to vancomycin; they were relatively resistant to erythromycin, clindamycin and beta-lactams antibiotics. Whilst Gram-negative organisms were relatively susceptible to imipenem (85%), ciprofloxacin (88%) and amikacin (87%), they had unacceptably low levels of susceptibility to cefuroxime (59.3%), cefotaxime (71%), ceftazidime (60.9%), and piperacillin (51.1%). This study shows that hospital-acquired bacteraemia in ICU patients carries a poor prognosis. Information regarding the infective agents and their susceptibility in the ICU setting is valuable for the selection of empirical therapy before culture and susceptibility results are known.     

Predictive value of abdominal obesity cut-off points for hypertension in blacks from west African and Caribbean island nations

BACKGROUND: Waist circumferences (WC) >/=94 cm for men and >/=80 cm for women (action level I) and >/=102 cm for men and >/=88 cm for women (action level II) have been suggested as limits for health promotion purposes to alert the general public to the need for weight loss. In this analysis we examined the ability of the above cut-off points to correctly identify subjects with or without hypertension in Nigeria, Cameroon, Jamaica, St Lucia and Barbados. We also determined population- and gender-specific abdominal adiposity cut-off points for epidemiological identification of risk of hypertension. METHODS: Waist measurement was made at the narrowest part of the torso as seen from the front or at midpoint between the bottom of the rib cage and 2 cm above the top of the iliac crest. Sensitivity and specificity of the established WC cut-off points for hypertension were compared across sites. With receiver operating characteristics (ROC), population- and gender-specific cut-off points associated with risk of hypertension were determined over the entire range of WC values. RESULTS: Predictive abilities of the established WC cut-off points for hypertension were poor compared to the specific cut-off points estimated for each population. Different values of WC were associated with increased risk of hypertension in these populations. In men, WC cut-off points of 76, 81, 80, 83 and 87 cm provided the highest sensitivity for identifying hypertensives in Nigeria, Cameroon, Jamaica, St Lucia and Barbados, respectively. The analogous cut-off points in women were 72, 82, 85, 86 and 88 cm. CONCLUSIONS: The waist cut-off points from this study represent values for epidemiological identification of risk of hypertension. For the purpose of health promotion, the decision on what cut-off points to use must be made by considering other additional factors including overall impact on health due to intervention (e.g. weight reduction) and potential burden on health services if a low cut-off point is employed. There is a need to develop abdominal adiposity cut-off points associated with increased risks for cardiovascular diseases in different societies, especially for those populations where the distribution of obesity and associated risk factors tends to be very different from those of the technologically advanced nations. International Journal of Obesity (2000) 24, 180-186