Infection-interactions in Ethiopian village chickens.

Chickens raised under village production systems are exposed to a wide variety of pathogens, and current or previous infections may affect their susceptibility to further infections with another parasite, and/or can alter the manifestation of each infection. It is possible that co-infections may be as important as environmental risk factors. However, in cross-sectional studies, where the timing of infection is unknown, apparent associations between infections may be observed due to parasites sharing common risk factors. This study measured antibody titres to 3 viral (Newcastle disease, Marek's disease and infectious bursal disease) and 2 bacterial (Pasteurella multocida and Salmonella) diseases, and the infection prevalence of 3 families of endo- and ecto-parasites (Ascaridida, Eimeria and lice) in 1056 village chickens from two geographically distinct populations in Ethiopia. Samples were collected during 4 cross-sectional surveys, each approximately 6 months apart. Constrained ordination, a technique for analysis of ecological community data, was used to explore this complex dataset and enabled potential relationships to be uncovered and tested despite the different measurements used for the different parasites. It was found that only a small proportion of variation in the data could be explained by the risk factors measured. Very few birds (9/1280) were found to be seropositive to Newcastle disease. Positive relationships were identified between Pasteurella and Salmonella titres; and between Marek's disease and parasitic infections, and these two groups of diseases were correlated with females and males, respectively. This may suggest differences in the way that the immune systems of male and female chickens interact with these parasites. In conclusion, we find that a number of infectious pathogens and their interactions are likely to impact village chicken health and production. Control of these infections is likely to be of importance in future development planning.

Altered fibroblast proliferation and apoptosis in diabetic gingival wounds.

Although it is known that diabetes impairs oral wound healing, relatively little is known about the cellular parameters affected, particularly in connective tissue. This study investigated the hypothesis that diabetes impairs connective tissue formation in healing gingiva, and that impaired healing is associated with factors that decrease fibroblast numbers. Full-thickness wounds were created in the palatal gingiva of type 1 and type 2 diabetic and normoglycemic mice. Five days after wounding, diabetic mice had less epithelial wound coverage, less new connective tissue formation, and reduced fibroblast density (p < 0.05). This occurred with increased numbers of caspase-3- and TUNEL-positive fibroblasts, decreased fibroblast proliferation, increased nuclear translocation of the pro-apoptotic transcription factor FOXO1, and increased numbers of polymorphonuclear leukocytes, all of which were significant (p < 0.05). The results suggest that diabetes may decrease fibroblast numbers through increased apoptosis and reduced proliferation, both of which may be mediated through increased activation of FOXO1.

Impaired wound healing in mouse models of diabetes is mediated by TNF-alpha dysregulation and associated with enhanced activation of forkhead box O1 (FOXO1).

AIMS/HYPOTHESIS: The role of TNF-alpha in impaired wound healing in diabetes was examined by focusing on fibroblasts. METHODS: Small excisional wounds were created in the db/db mice model of type 2 diabetes and normoglycaemic littermates, and in a streptozotocin-induced type 1 diabetes mouse model and control mice. Fibroblast apoptosis was measured by the TUNEL assay, proliferation by detection of proliferating cell nuclear antigen, and forkhead box O1 (FOXO1) activity by DNA binding and nuclear translocation. TNF-alpha was specifically inhibited by pegsunercept. RESULTS: Diabetic wounds had increased TNF-alpha, fibroblast apoptosis, caspase-3/7 activity and activation of the pro-apoptotic transcription factor FOXO1, and decreased proliferating cell nuclear antigen positive fibroblasts (p < 0.05). TNF-alpha inhibition improved healing in the diabetic mice and increased fibroblast density. This may be explained by a decrease in fibroblast apoptosis and increased proliferation when TNF-alpha was blocked (p < 0.05). Although decreased fibroblast proliferation and enhanced FOXO1 activity were investigated in type 2 diabetes, they may also be implicated in type 1 diabetes. In vitro, TNF-alpha enhanced mRNA levels of gene sets related to apoptosis and Akt and p53 but not mitochondrial or cell-cycle pathways. FOXO1 small interfering RNA reduced gene sets that regulate apoptosis, Akt, mitochondrial and cell-cycle pathways. TNF-alpha also increased genes involved in inflammation, cytokine, Toll-like receptor and nuclear factor-kB pathways, which were significantly reduced by FOXO1 knockdown. CONCLUSIONS/INTERPRETATION: These studies indicate that TNF-alpha dysregulation in diabetic wounds impairs healing, which may involve enhanced fibroblast apoptosis and decreased proliferation. In vitro, TNF-alpha induced gene sets through FOXO1 that regulate a number of pathways that could influence inflammation and apoptosis.

Incidence of neonatal morbidity at Gondar town, Ethiopia.

OBJECTIVE: To determine the incidence and pattern ofneonatal morbidity. DESIGN: For all neonates delivered in the hospital at least one home visit was arranged to collect morbidity data during neonatal period. This collection took place for a period of one year from 1 September 1995 to 31 August 1996. SETTING: Maternity Ward of the Gondar College of Medical Sciences Hospital. PATIENTS: 320 neonates were visited at home and were evaluated for any morbidity. RESULTS: Of the 320 neonates visited at home during the first 24 to 38 days post delivery 83 (25.9%) were found to be sick. URTI (Upper Respiratory Tract Infection), jaundice, pneumonia and neonatal septicimia were diagnosed by physical examination. Non-breastfeeding was associated with neonatal morbidity (p<0.001). CONCLUSIONS: The neonatal morbidity found during the home visit in this study is very high. A concerted effort is needed to improve both antenatal and postnatal care services to prevent neonatal morbidity and to identify sick neonates timely to provide appropriate care in this setting.

Inhibition of experimental periodontitis by a topical boron-based antimicrobial.

AN0128 is a boron-containing compound with antibacterial and anti-inflammatory properties. To test its potential effectiveness in treating periodontal disease, we induced experimental periodontitis in the rat by placing ligatures and assessed the impact of AN0128 and positive and negative controls by micro-CT and histologic measurements. The formation of an inflammatory infiltrate was measured in hematoxylin-and-eosin-stained sections. Daily application of AN0128 (1%) compared with controls reduced bone loss by 38 to 44% (P < 0.05), while vehicle alone had no effect (P > 0.05). The reduction in bone loss with AN0128 was similar to that achieved with a NSAID, ketorolac, and Total toothpaste containing triclosan. AN0128 also reduced the level of gingival inflammation 42% compared with the ligature only (P < 0.05), whereas vehicle alone had no effect (P > 0.05). The results indicate that AN0128 significantly reduces the formation of an inflammatory infiltrate and reduces bone loss, measured histologically and by micro-CT.

Diabetes enhances periodontal bone loss through enhanced resorption and diminished bone formation.

Using a ligature-induced model in type-2 Zucker diabetic fatty (ZDF) rat and normoglycemic littermates, we investigated whether diabetes primarily affects periodontitis by enhancing bone loss or by limiting osseous repair. Diabetes increased the intensity and duration of the inflammatory infiltrate (P < 0.05). The formation of osteoclasts and percent eroded bone after 7 days of ligature placement was similar, while four days after removal of ligatures, the type 2 diabetic group had significantly higher osteoclast numbers and activity (P < 0.05). The amount of new bone formation following resorption was 2.4- to 2.9-fold higher in normoglycemic vs. diabetic rats (P < 0.05). Diabetes also increased apoptosis and decreased the number of bone-lining cells, osteoblasts, and periodontal ligament fibroblasts (P < 0.05). Thus, diabetes caused a more persistent inflammatory response, greater loss of attachment and more alveolar bone resorption, and impaired new bone formation. The latter may be affected by increased apoptosis of bone-lining and PDL cells.

Modeling the internal dynamics of energy and mass transfer in an imperfectly mixed ventilated airspace.

UNLABELLED: The present paper outlines a modeling approach, which has been developed to model the internal dynamics of heat and moisture transfer in an imperfectly mixed ventilated airspace. The modeling approach, which combines the classical heat and moisture balance differential equations with the use of experimental time-series data, provides a physically meaningful description of the process and is very useful for model-based control purposes. The paper illustrates how the modeling approach has been applied to a ventilated laboratory test room with internal heat and moisture production. The results are evaluated and some valuable suggestions for future research are forwarded. PRACTICAL IMPLICATIONS: The modeling approach outlined in this study provides an ideal form for advanced model-based control system design. The relatively low number of parameters makes it well suited for model-based control purposes, as a limited number of identification experiments is sufficient to determine these parameters. The model concept provides information about the air quality and airflow pattern in an arbitrary building. By using this model as a simulation tool, the indoor air quality and airflow pattern can be optimized.

Tumor necrosis factor modulates fibroblast apoptosis, PMN recruitment, and osteoclast formation in response to P. gingivalis infection.

P. gingivalis is an important oral pathogen, which has been closely linked to periodontal disease as well as lesions of endodontic origin. Both infections are associated with a decrease in fibroblast numbers, formation of an inflammatory infiltrate, and bone resorption. The goal of this study was to investigate the role that the host response plays in the capacity of P. gingivalis to stimulate fibroblast apoptosis, PMN recruitment, and osteoclastogenesis. This was accomplished by the use of an in vivo calvarial model in mice with targeted deletion of TNF receptors p55 and p75 and matched wild-type mice. The results indicate that P. gingivalis induces fibroblast apoptosis in vivo and establish for the first time that this involves the stimulation of a host response. Moreover, bacteria-stimulated PMN recruitment and osteoclastogenesis were also dependent upon the host response. The results suggest that much of the damage caused by P. gingivalis infection, including fibroblast apoptosis, at least under some circumstances, results from stimulation of the host response rather than the direct effect of bacterial products. Furthermore, this may represent a more general mechanism by which bacterial challenge induces apoptosis of matrix-producing cells through the induction of TNF.

In vitro evaluation of antibiotic prophylaxis in the prevention of biliary stent blockage.

BACKGROUND: Bacterial adherence and biofilm formation are important factors in the blockage of biliary stents. Clinical studies with oral antibiotic prophylaxis to prevent stent blockage have produced conflicting results. The aim of this study was to evaluate the in vitro effect of single antibiotic (ciprofloxacin, ceftazidime, or ampicillin) treatment on adherence of Escherichia coli and Enterococcus to plastic stents. METHODS: Selected clinical isolates of E coli and Enterococcus were perfused through a modified Robbins device containing segments of polyethylene stents. The stents were removed daily and the number of bacteria attached was measured. The effect of antibiotic treatment on bacterial adherence was tested by the perfusion of individual antibiotics into separate modified Robbins devices using a side-arm adaptor and the results were compared with saline controls. RESULTS: Compared with the saline controls, ciprofloxacin and ceftazidime caused a 10- to 100-fold reduction in the number of E coli attached to the stents, whereas ampicillin had no effect on adherence of E coli. Ampicillin caused a 5- to 10-fold reduction in Enterococcus adherence but there was no change with ceftazidime. Sustained reduction in E coli adherence was observed with prolonged ciprofloxacin perfusion. CONCLUSION: Timely treatment with appropriate antibiotics reduced bacterial adherence in vitro and may be potentially beneficial in the prevention of stent blockage.

Is there a synergistic effect between mixed bacterial infection in biofilm formation on biliary stents?

BACKGROUND: Biliary sludge which forms as a result of bacterial adherence and biofilm formation in the biliary system is a recognized cause of blockage of plastic stents. Bacteriological cultures of sludge have revealed a mixed infection with gram-positive and gram-negative bacteria. Animal studies have shown that prophylactic ciprofloxacin, which selectively suppress gram-negative bacteria, results in prolonged stent patency despite colonization of the stents by gram-positive bacteria. METHODS: We tested a possible synergistic effect between gram-negative and gram-positive bacteria in adherence and biofilm formation on plastic stents. Clinical isolates of Escherichia coli and Enterococcus were cultured in separate chemostats to achieve a steady growth. Adherence of the two bacteria on plastic stent surface were tested separately by perfusing infected bile with the respective bacteria through different modified Robbins devices containing 10F polyethylene stent pieces up to 4 days. In a second experiment, Enterococcus was perfused through stent pieces precolonized with E. coli for 24 hours. The stent pieces were then removed daily and analyzed by bacteriologic culture and scanning electron microscopy for bacterial adherence and biofilm formation. RESULTS: Gram-negative E. coli were more adherent than gram-positive Enterococcus. Precolonization with E. coli facilitates subsequent attachment of Enterococcus. CONCLUSIONS: We concluded that there is a synergistic effect between gram-positive and gram-negative bacteria in adherence and biofilm formation.

Performance of health workers after training in integrated management of childhood illness in Gondar, Ethiopia.

The performance of six primary health workers was evaluated after following a 9-day training course on integrated management of childhood illness (IMCI). The participants were selected from three primary health centres in the Gondar District, Ethiopia, and the course was focused on assessment, classification, and treatment of sick children (aged 2 months to 5 years) and on counselling of their mothers. Immediately following this training, a 3-week study was conducted in the primary health centres to determine how well these workers performed in assessing, classifying and treating the children and in counselling the mothers. A total of 449 sick children who presented at the three primary health centres during the study period were evaluated. Most of the complaints (87%) volunteered by the mothers (fever, cough, diarrhoea, and ear problems) were covered by the IMCI charts. The assessment of commonly seen signs (tachypnoea or ear pain) or easily identifiable signs (slow return after skin pinch, wasting, or pedal oedema) was good, with sensitivities of 67-91%, whereas the assessment of uncommonly seen signs (dry mouth, corneal clouding) or less easily quantifiable signs (eyelid pallor, absence of tears) had a fair or poor sensitivity of 20-45%. The classification of pneumonia, diarrhoea with signs of dehydration, and malnutrition showed sensitivities of 88%, 76%, and 85% and specificities of 87%, 98%, and 96%, respectively. However, the classification of febrile illnesses had a sensitivity of only 39% due to problems in using the draft algorithm in areas with a mixture of high, low, and no malaria risk, and due to confusion between axillary and rectal temperature thresholds. Of 39 children classified as having severe disease, 9 were misclassified, mostly by one nurse. Treatment of patients improved over the three weeks of observation, their completeness increasing from 69% to 88%. Health workers usually communicated appropriate advice to the mother. They learned to use checking questions but failed to adequately solve problems in the majority of cases. The mother's counselling card, which summarized recommendations on feeding and home fluids, and advice on when to return, was widely used to aid communication. The time taken to perform the complete management of children did not change significantly (20 to 19 minutes) during the study. Lessons from our findings have been incorporated into an improved version of the IMCI charts.

PIP: 6 outpatient clinic nurses selected from 3 primary health centers in the Gondar District of Ethiopia were trained over the course of 9 days in the integrated management of childhood illnesses (IMCI), after which their performance was evaluated. The training course focused upon the assessment, classification, and treatment of sick children aged 2 months to 5 years, and upon the counselling of their mothers. Immediately following the training, the trainees were observed working in the health centers for a 3-week period to determine how well they assessed, classified, and treated children, and counseled mothers. 449 children who presented at the centers during the study period were evaluated. 87% of the complaints noted by the mothers on fever, cough, diarrhea, and ear problems were covered by the IMCI charts. There was good assessment of commonly seen signs such as tachypnoea and ear pain, as well as of readily identifiable signs such as a slow return after skin pinch, wasting, and pedal oedema; sensitivities were 67-91%. However, sensitivities were only 20-45% for rarely seen signs such as dry mouth and corneal clouding and the more difficult to recognize signs of eyelid pallor and the absence of tears. The classification of pneumonia, diarrhea with signs of dehydration, and malnutrition had sensitivities of 88%, 76%, and 85%, and specificities of 87%, 98%, and 96%, respectively. The classification of febrile illnesses was 39% sensitive. 9 of 39 children with severe disease were misclassified, mostly by one nurse. Patient treatment improved over the 3 weeks of observation and health workers usually communicated appropriate advice to mothers.

A labor and delivery service unit model for a multihospital health maintenance organization.

Number of deliveries is no longer a relevant measurement for allocation of nursing resources in labor and delivery. A service unit model, which reflected the nursing effort to care for labor and delivery patients and the variability and unpredictability of these patients' needs, was designed for a major multihospital system. The development of the Labor and Delivery Service Unit Model for the Northern California Region of the Kaiser Permanente Medical Care Program is described.

Diabetic ketoacidosis in an Addis Abeba children's hospital.

A retrospective study was carried out to determine the precipitating factors and clinical profiles of diabetic ketoacidosis (DKA) among 46 paediatric patients (mean age 9 yrs) with 52 episodes admitted to the Ethio-Swedish Children's Hospital (ESCH) from January 1, 1982 to December 30, 1988. Thirty (58%) episodes occurred in newly diagnosed diabetics and 22 (42%) episodes in known diabetics. The most common precipitating factors were infection (52%), omission of insulin (16%) and parasitic infection (12%). The mortality rate was 6%, with all fatal cases occurring in previously undiagnosed diabetics. Several of these episodes of DKA may have been prevented by prompt and effective treatment of infections and proper health education.

A study and analysis of spinal canal diseases in the Black Lion Hospital by myelography.

Sixty seven lumbar and thoracic myelographic examinations were performed during the period February 1987 to September 1988. Fourteen patients (21%) had normal myelography while 53 (79%) patients had pathological findings. Spinal canal tumours accounted for the majority of complete CSF blocks (76.7%) Seventy-five per cent of the intradural tumours showed no abnormality on plain films of the vertebral column, whereas 75% of the extradural tumours had pathological findings. Dorsal (central) disc herniation was more frequent (70%) than lateral herniation with almost equal distribution at L5-S1 and L4-L5 disc spaces. Central disc herniation was more common at L4-L5 (71%). The measurement of the interpedicular distance on plain radiograph was not found to be diagnostic in our single case of spinal stenosis.

A survey of colonic pathology with a double contrast method and analysis of the indication for a barium enema.

A prospective study of colonic pathology with double contrast method was made of 146 patients sent to the X-ray department of the Black Lion Hospital, Addis Ababa. The barium enemata were done for complaints like constipation, diarrhoea, rectal bleeding and palpable abdominal mass often without any relevant prior physical clinical examinations. Of those examined only 26 (17.8%) patients were found to have radiologically colonic pathology and the rest, 120 (82.2%) patients were reported normal. The policy of prior clinical examination before any barium enema such as rectal digital examination, sigmoidoscopy and stool occult blood studies would reduce the normal barium enema. The survey compared bowel preparation with adequate fluid intake and laxative without cleansing enema serves as a good method of bowel preparation for ambulatory patients.