Simulation study on quality of CPR between manual chest compression and mechanical chest compression devices performed in ambulance.

BACKGROUND: Maintaining good quality CPR while transporting out-of-hospital cardiac arrest patients is very challenging. We aim to determine how different ambulance speed can affect the quality of chest compression performed either manually or mechanically. METHODS: This was an observational manikin-based study. A total of 96 participants as well as two types of mechanical compression devices: Lucas-2 and AutoPulse, performed one minute of continuous chest compression on BT-CPEA programmed manikin while the ambulance travelled at different speeds, i.e., idle state, 30km/hr and 60km/hr. Seven outcome variables of chest compression were measured. Performance data of different groups of compressor were compared and analysed using repeated measures analysis of variance (ANOVA). RESULTS: In manual chest compression, significant variation were noted among different speeds in term of average compression rate (p<0.001), average compression depth (p=0.007), fraction of adequate/insufficient compression depth and fraction of normal hands positioning with p=0.018, 0.022 and 0.034 respectively. Overall, AutoPulse and Lucas-2 were not affected by ambulance speed. Lucas- 2 showed more consistent average compression rate, higher fraction of adequate compression depth and reduced fraction of insufficient compression depth as compared to manual compression with p<0.001, 0.001 and 0.043 respectively. CONCLUSION: In this study we found that ambulance speed significantly affected certain aspects of manual chest compression most notably compression depth, rate and hand positioning. AutoPulse and Lucas-2 can improve these aspects by providing more consistent compression rate, depth and fraction of adequate compression depth during transport.

Consensus-led recommendations defining practical principles of achieving optimal surgical outcomes in robotic colorectal surgery in the Asia-Pacific region.

Recent innovations within the field of robotic surgery have particular relevance to colorectal surgery. Although a robotic approach has been associated with satisfactory outcomes, there remains a wide variation in levels of adoption. In particular, this study focuses on patient positioning, docking, and table placement, with the intent of understanding the strength of opinion of colorectal surgeons in the Asia-Pacific region to the practical application of these developments to achieve optimal surgical outcomes. Using a modified Delphi methodology, a steering group of colorectal surgeons with experience in robotic surgery from across the Asia-Pacific region identified 35 consensus statements. An online 4-point Likert scale questionnaire was distributed to surgeons in the Asia-Pacific region using convenience sampling. Respondents were excluded from further analysis if they did not perform colorectal surgery or had no experience in robotic surgery. A total of 140 responses (71.8% response rate) were received between August and October 2021. 22 statements attained a very high degree of agreement (≥ 90%). High agreement (< 90% and ≥ 75%) was achieved in another 12, and one failed to meet the consensus threshold (< 75%). A set of five recommendations were developed based on these results. The high levels of agreement demonstrate recognition amongst colorectal surgeons within the Asia-Pacific region of the potential advantage of recent improvements in robotic surgery technology to further improve surgical outcomes. The recommendations may inform a set of practical principles to help standardise the use of colorectal robotic surgery, which may also be relevant to other surgical fields.

Correlation between serum levels of antibodies to the 96-kD antigen of Plasmodium falciparum and protective immunity in Cameroon: a longitudinal study.

A longitudinal study was conducted in the Yaounde area of Cameroon that involved 211 individuals in June 1990, and 70 individuals for the follow-up study in December 1990. Sera from these subjects were tested against the recombinant 96-thermoresistant antigen of Plasmodium falciparum and the kinetics of antibody production to this protein show that titers tend to increase with age and are also related to antigen exposure. The increase in antibody titers with age correlates positively with the ability of the individual to prevent development of a high parasitemia. Adults who maintained stable high titers generally did not experience clinical attacks during the study period. The data suggest that antibodies against the 96-kD antigen participate in conferring some immunity to falciparum malaria.

Characterization of a recombinant Onchocerca volvulus antigen (Ov33) produced in yeast.

A yeast (Saccharomyces cerevisiae) expression system has been adapted to produce reagent quantities of a major Onchocerca antigen, Ov33. Using a pool of monoclonal antibodies produced against third-stage larvae, a cDNA library constructed from adult O. volvulus worms was screened. Twenty-seven cDNAs were isolated, two of which had sequence homology to Ov33, a putative aspartyl protease inhibitor, which is the immunodominant antigen of O. volvulus. These cDNAs were expressed at high levels intracellularly or through the secretory pathway of S. cerevisiae. Localization studies using antisera produced against purified recombinant protein demonstrated that Ov33 is a very abundant parasite protein present in the hypodermis, muscle, and uterus of female worms, as well as in embryonic microfilariae. The soluble recombinant protein secreted by yeast (C71) demonstrated inhibitory activity against the aspartyl protease pepsin. Antibodies to the recombinant protein-mediated leukocyte adherence to and killing of skin microfilariae. The sensitivity of a diagnostic test using recombinant Ov33 was evaluated using sera from 441 patients. The mean sensitivities for the two recombinant constructs, C27 and C71, were 82.2% and 85.4%, respectively. The combined sensitivity using both recombinant proteins was 94%.

The epidemiology of Plasmodium falciparum malaria in two Cameroonian villages: Simbok and Etoa.

In support of ongoing immunologic studies on immunity to Plasmodium falciparum, demographic, entomologic, parasitologic, and clinical studies were conducted in two Cameroonian villages located 3 km apart. Simbok (population = 907) has pools of water present year round that provide breeding sites for Anopheles gambiae, whereas Etoa (population = 485) has swampy areas that dry up annually in which A. funestus breed. Results showed that individuals in Simbok receive an estimated 1.9 and 1.2 infectious bites per night in the wet and dry season, respectively, whereas individuals in Etoa receive 2.4 and 0.4 infectious bites per night, respectively. Although transmission patterns differ, the rate of acquisition of immunity to malaria appears to be similar in both villages. A prevalence of 50-75% was found in children < 10 years old, variable levels in children 11-15 years old, and 31% in adults. Thus, as reported in other parts of Africa, individuals exposed to continuous transmission of P. falciparum slowly acquired significant, but not complete, immunity.

Variation in delayed hypersensitivity in onchocerciasis.

Soluble antigen preparations were made from Onchocerca volvulus adults recovered from subcutaneous nodules, and from Necator americanus third-stage larvae. Intradermal skin tests were carried out on a total of 100 individuals clinically classified as having either the generalized form of onchocerciasis (86 cases, or the localized sowda form (14 cases). 91 of the people studied produced immediate reactions to the onchocercal antigen, but only those with sowda showed delayed reactions, though one person with generalized disease showed a doubtful delayed reaction. Reactions to N. americanus antigen, both immediate and delayed, were seen in both forms of the disease. The lack of delayed skin reaction in the generalized form of onchocerciasis is discussed, and a comparison is made with other diseases. Preliminary evidence for the existence of a true spectrum of clinical and immunological forms of onchocerciasis is suggested by one case in this study.

Immunological studies on onchocerciasis. Varying skin hypersensitivity and leucocyte migration inhibition in a clinical spectrum of the disease.

Soluble antigen was prepared from adult worms and microfilariae of Onchocerca volvulus. In 27 patients clinically characterized as having generalized type (17) and localized reaction type (10) onchocerciasis, the response to this antigen was assessed in vivo by skin testing and in vitro by leucocyte migration inhibition assay. Three varieties of skin hypersensitivity were observed: Immediate, Arthus-type and delayed or type IV hypersensitivity. The first 2 occurred in all patients, but type IV hypersensitivity was noted only in 10, eight of whom had localized reactive type onchocerciasis, whilst the other 2 had mild generalized lesions which had for the most part healed with treatment. The leucocyte migration inhibition assay showed a spectrum of responsiveness with significant inhibition in the presence of antigen in 8 patients with localized lesions and in 2 others with mild generalized disease which had largely healed.--The specificity of the skin reaction and leucocyte migration inhibition to the antigen used was confirmed by the results obtained when a control group of 18 subjects, with no evidence of previous filarial infection, was similarly tested. 16 of them showed no skin hypersensitivity and 2 had a doubtful immediate reaction. No significant inhibition of leucocyte migration in the presence of antigen was noted in this group.

Selective recovery of living microfilariae from Onchocerca volvulus nodules. Determination of optimal conditions for their culture in vitro for excretory/secretory products.

A method for the selective recovery of living microfilariae from Onchocerca volvulus nodules is described. The microfilariae migrate through solidified agar gel into overlayering Hanks balanced salt solution (HBSS). The highest recovery rates of the worms were obtained with 0.3 and 0.4% agar. Optimal conditions for in vitro cultures of the larvae in HBSS were established; pH range 7.0-7.5, glucose concentration 2-5 mg/ml for long term cultures, osmolality 200-309 mOsmoles/l, temperature 4 degrees C for prolonged cultures and 24-28 degrees C for overall best yield of excretory/secretory products (ESP). Subculturing of the larvae reduced contamination of ESP with human serum protein to minimal amounts after 9 recultures done within 96 h.

Nephropathy in Cameroon: evidence for filarial derived immune-complex pathogenesis in some cases.

This study was carried out in two parts. Part 1 consisted of an epidemiological survey of 1011 subjects aged 3-65 yrs from 2 adjoining villages hyper-endemic for Onchocerciasis and 890 subjects in a control area, relatively free from this infection but otherwise with a similar parasitological profile. There was a significantly higher prevalence of proteinuria in subjects from the onchocercal zone than in controls (observed difference greater than 5 1/2 times its standard error). Part 2 comprised detailed investigations, including renal biopsy, of 63 consecutive patients admitted into hospital with severe proteinuria and/or renal failure from a caption area extending into the onchocercal zone. There were a variety of causative factors, but in 9 cases filarial antigen was demonstrable in the immune-complex deposits in the kidney. A plenum of renal histopathological changes were seen in patients with onchocerciasis. The significance of these findings is discussed.

Patterns of antibody levels to the 96 tR recombinant protein of Plasmodium falciparum in children over a six-month period.

Several Plasmodium falciparum asexual stage antigens have been reported as possible candidate antigens for vaccines against malaria. One such is the 96-kDa antigen. We used the 96 tR recombinant protein to determine the levels of antibodies to this protein over a 6-mo period in children 4 mo to 15 yr old, who make up the population at risk in Cameroon. The mean enzyme-linked immunosorbent assay (ELISA) on 83 children at the start of the study in June was 0.270, with 13% of these children having ELISA values considered to be positive (> or = 0.36). In the follow-up study in early December, the mean ELISA was 0.320 with 20% of the children having positive values. In the period between June and December, 85% of the children who returned for follow-up had had 1 or more attacks of malaria. The mean ELISA values of this latter group had increased from 0.235 in June to 0.318 in December, with 6% of the children in June having positive values compared with 18% in December. These findings reinforce our evidence from a previous study that reactivity to the 96-kDa antigen is related to adequate exposure or repeated infection.

Adult response to initial treatment with ampicillin in community acquired pneumonia in Yaoundé, Cameroon.

A prospective study was conducted to evaluate the efficacy of ampicillin as an initial therapy in 60 adult patients with community acquired pneumonia. Bacteriological etiology was obtained only in 24 (40pc) patients by microscopic examination, culture and antigen detection. Streptococcus pneumoniae was the leading causative agent identified in 15 cases. Other etiologies were Klebsiella pneumoniae (3), Streptococcus pyogenes (2) Staphylococcus aureus (2), Haemophilus influenzae (1) and Moraxella catarrhails (1). Patients were started on ampicillin one gram twice daily, empirically, and treated for 10 days. There were 52(86.7pc) patients cured, two(3.3pc) patients improved and six (10pc) were therapeutic failures. The causative agents in patients with failures were: Klebsiella pneumoniae (1), Staphylococcus aureus (1), Streptococcus pneumoniae (1) and unknown in three cases. Only six of 60 patients still febrile after three days were switched to amoxycillin/clavulanic acid or cefaclor according to culture results and susceptibilities or to roxythromycin because no organisms were isolated. Side effects were observed in only one (1.7pc) patient who developed a mild skin rash. Due to its low cost and its high efficacy, ampicillin still appears to be the drug of choice in adult community acquired pneumonia in our region.

[Variations under genetic control of onchocerca infection as a function of clinical profile in the endemic center of Cameroon]. / Variations sous contrôle génétique de l'infection onchocerquienne en fonction du profil clinique dans les foyers endémiques du Cameroun.

Onchocerciasis, also known as "river blindness", presents a plenum of clinical manifestations which vary from one individual to another, and from one area to another. This large spectrum of clinical manifestations of the disease is an indication of the complexity of the pathogenesis of onchocerciasis and suggests that many interacting factors might influence the clinical features of the disease. The present study has focused on the heterogenicity of the host immune response as a plausible explanation for differences in clinical manifestations of the infection. Host genetic factors, namely HLA genes, might play an important role in determining the nature of the immune response mounted against the parasite Onchocerca volvulus, and thus the development of different manifestations of the infection. Genetic diversity of onchocerciasis was assessed in different endemic foci in Cameroon. In order to investigate the possibility that the Major Histocompatibility Complex (MHC) genes might be associated with the different clinical types of onchocerciasis, 146 subjects living in three endemic areas of Cameroon were studied. They were classified in four groups: A (asymptomatic subjects), P (putatively immune subjects) L (patients with localised disease) and G (patients with generalised disease). The four groups differed in the distribution of HLA class II alleles as determined by Direct Heteroduplex Analysis. On the one hand, allele HLA-DQA1*0501 appeared to be associated with protection against severe onchocerciasis; on the other, allele HLA-DQB1*0201 might play an important role in the severe form of the disease.

Resistant hypertension in Yaounde.

Sixty six consecutive patients with resistant hypertension were studied over a period of 12 months. During that same period 565 patients were seen in all for hypertension given an average prevalence of 11.7% of resistant hypertension. Men were more frequently affected, however mean systolic and diastolic blood pressure levels were higher in women. Past history of poor compliance, overweight, renal impairment and cardiac abnormalities were important predictors of poor response to therapy. Resistance to therapy was not related to the class or the type of medication taken. Side effects were more numerous in the resistant group. Biochemically, apart from abnormal renal function tests, the other baseline tests were similar in both groups of resistant and non resistant hypertensives.

Glycolipid antigens of adult O. volvulus reactive with patients sera from onchocerciasis endemic areas in Cameroon.

Lipid extraction of adult O. volvulus worms using a chloroform/methanol/water mixture yielded 10 lipid fractions of which 8 were demonstrated by the orcinol reagent to be glycolipids. In TLC, two of these lipid fractions had mobilities similar to cholesterol and cholesterol ester (Rf.: 0.95, 0.86) whereas two others migrated as sphingomyelin and lecithin (Rf.: 0.40, 0.35) respectively. Other components migrated at intermediate positions. The glycolipids were immunologically active and reacted with sera from onchocerciasis patients. The highest reaction was obtained with the IgG antibody class, followed by IgM while no appreciable reactivity was observed with IgE. Sera from patients infected with other filariae such as Loa-loa and Dipetalonema perstans did not show any significant reaction with these antigens. The significance of these results is discussed.

An evaluation of the reactivity of the card agglutination test for trypanosomiasis (CATT) reagent in the Fontem sleeping sickness focus, Cameroon.

The TestrypR Card Agglutination Test for Trypanosomiasis (CATT) used for the serodiagnosis of gambiense trypanosomiasis is based on the variant antigen type (VAT) LiTat 1.3. This antigen is rarely expressed by trypanosomes in the Fontem focus of Cameroon, but the CATT has been used for serodiagnosis in the focus since 1985. We give here a summary of results obtained with the CATT in Fontem from 1985 to 1989. The CATT is specific for trypanosome antibodies since: (a) sera from persons with other parasitoses from areas non endemic for trypanosomiasis fail to react and (b) an enzyme-linked immunosorbent assay (ELISA) based on the detection of antibodies to somatic antigens of T.b gambiense from Fontem concorded with the CATT. CATT reactions in Fontem seem to be specific for the variant surface glycoprotein (VSG) since absorption of CATT reactive sera with formalin fixed bloodstream T. gambiense from Fontem and with culture produced procyclics of T. gambiense from Fontem failed to abrogate CATT reactivity. CATT on serum failed to confirm 37% of CATT positive cases on whole blood. Although immunoconglutinin (IK), anti-human red blood cell (RBC) antibodies and complement fixing immune complexes (ICs) were found in sera from Fontem, our results failed to incriminate immunoconglutination of RBCs, reactions of RBCs with their autoantibodies and immune adherence hemagglutination as contributory factors in this lack of agreement between CATT on serum and whole blood. Further, comparison of whole blood and serum CATT results of parasitologically confirmed patients leads to the conclusion that screening with the CATT in the Fontem focus should be done on whole blood, not serum or plasma. CATT reactions in Fontem are based on cross-reactions with as yet undefined VATs.