Centrifugal Sedimentation Technique Research Articles

Zoonotic Enteric Nematodes and Dermatophytes in Cat Cafés: An Investigation in the Bangkok Metropolitan Area, Thailand.

Cat cafés have gained significant popularity worldwide, offering a unique interface between humans and cats. The present study aims to assess the prevalence of potentially zoonotic endoparasites and dermatophytes from cats living in cat cafés situated in the Bangkok metropolitan area in 2017-2018. Cat fecal samples were subjected to microscopic examination employing centrifugal flotation and centrifugal sedimentation techniques. The hair samples from every cat were cultured on a dermatophyte test medium and Sabouraud dextrose agar and subsequently confirmed by visualization of the typical colony and macroconidia morphology. Findings from 11 cat cafés indicated an 18.2% (2/11) prevalence of gastrointestinal parasites, including Toxocara spp., Ancylostoma spp., Physaloptera spp., and Eucoleus aerophilus. Dermatophytes were prevalent in 16.2% (32/198) of the total number of cats tested, with Microsporum canis being the sole species identified. Notably, the presence of dermatophyte was significantly correlated with the presence of skin lesions and the cats' origin. In summary, the findings of this study have provided evidence of potentially zoonotic endoparasites and dermatophytes in cats residing in cat cafés. Therefore, it is imperative to heighten awareness and encourage preventive measures among cat café owners and customers to halt the dissemination of these pathogens.

Spurious infection by Calodium hepaticum (Bancroft, 1983) Moravec, 1982 and intestinal parasites in forest reserve dwellers in Western Brazilian Amazon.

ABSTRACTSubsistence hunting is the main source of protein for forest reserve dwellers, contributing to the development of spurious infections by Calodium hepaticum, frequently associated with the consumption of the liver from wild mammals. The prevalence of infections by soil-transmitted helminths (STHs) and intestinal protozoa is considered an indicator of the social vulnerability of a country, besides providing information on habits, customs and quality of life of a given population. Intestinal parasites mostly affect poor rural communities with limited access to clean water and adequate sanitation. This study reports the results of a parasitological survey carried out in 2017 and 2019, in two municipalities (Xapuri and Sena Madureira) in Acre State. Stool samples were collected from 276 inhabitants. Upon receipt, each sample was divided into two aliquots. Fresh samples without preservative were processed and examined by the Kato-Katz technique. Samples fixed in 10% formalin were processed by the spontaneous sedimentation and the centrifugal sedimentation techniques. Calodium hepaticum eggs were found in three stool samples. The overall STH prevalence was 44.9%. The hookworm prevalence (19.2%) was higher than that of Ascaris lumbricoides (2.5%) and Trichuris trichiura (0.7%), an unexpected finding for municipalities belonging to the Western Brazilian Amazon. When considering parasites transmitted via the fecal-oral route, Endolimax nana and Entamoeba coli showed the highest positivity rates, of 13% and 10.9%, respectively. This study is the first report of spurious infection by C. hepaticum among forest reserve dwellers that consume undercooked liver of lowland pacas. Additionally, this is the first report of Blastocystis sp. in Acre State.

Prevalence of strongylids of pigs in Ogun State, southwest Nigeria

This study was carried out to determine the prevalence of strongyles infecting pigs in Ogun State , Southwestern Nigeria. Faecal samples were collected from 209 pigs which were initially screened by centrifugal sedimentation technique. Faeces positive nematode eggs were then cultured using a modified Baermann's technique. Out of the 36.8% (77/209) infected pigs, 84.4%, 58.4%, 57.1%, 19.5% and 6.5% were for Hyostrongylus rubidus, Trichostrongylus colubriformis, Oesophagostomum spp., Strongyloides ransomi and Dictyocaulus viviparus respectively. Mixed infection with various nematode species accounted for 94.8% of the prevalence. The infection rate in piglets (43.7%) was higher than in weaners and adults without any significant differences. Similarly no significant differences were observed between diarrhoeic and non-diarrhoeic pigs. The results of this study thus showed the economic importance of strongylid nematode infections in intensively reared pigs in Ogun state. Regular screening to ascertain worm load and species involved will facilitate appropriate control and prevention strategies.

Prevalence of Intestinal Parasitosis in Children of a Primary School in Pedro Juan Caballero - PY

Introduction: Parasitosis is a type of endoparasitism, which is directly related to sanitary conditions and is an important public health problem in developing countries. Objective: To determine the prevalence of intestinal parasites in children attending a primary public school in Pedro Juan Caballero - PY. Materials and Methods: 85 (eighty-five) stool samples were analyzed using the centrifugal sedimentation technique. Results: Cysts and/or parasite eggs were observed in the stool samples of 67 (78.8%) children. Giardia lamblia cysts were those that showed the highest incidence in the children. Conclusion: The high Giardia lamblia index demonstrates the lack of access to drinking water for consumption, inadequate sanitation and the absence of a public health network. This study highlights the importance of encouraging the use of serial analysis of stool, strengthening preventive measures for parasitosis, developing protocols for their approach, and designing a strategy that includes the preschool population in the programs that periodically evaluate the development of children.

Preparation and Characterization of Stabilizer-Free Phytantriol-Based Water-in-Oil Internally Liquid Crystalline Emulsions

Despite the widespread use of surfactants, there are known issues such as allergic reactions and formulation complications in their use as emulsion stabilizers. In this study, stabilizer-free water-in-oil (W/O) emulsions containing water, phytantriol, and almond oil were prepared by an ultra-turrax homogenizer, a standard laboratory equipment, and a high specialized high-shear device. Parameters such as mixing time, stirring rate, composition, order of addition of phases, and temperature were investigated to systematically optimize the preparation of the formulations through evaluating their accelerated physical stability by a centrifugal sedimentation technique. The liquid crystalline structure of the continuous phase was studied by small-angle X-ray scattering indicating a reverse hexagonal phase (H2). Microscopy images showed the emulsions prepared via high-shear method had smaller water droplets with more uniform shape and better dispersion as confirmed by Fourier-transform infrared–attenuated total reflection spectroscopy. Rheology studies showed a larger yield stress value for emulsions with higher content of phytantriol. Our results indicated that emulsions prepared by the high-shear device with higher amount of phytantriol were the most stable formulations. Applying the correct variables in the preparation of the stabilizer-free emulsions using ultra-turrax homogenizer, one could obtain similarly stable emulsions lacking the uniformity of the droplets.

A Survey of Urinary Schistosomiasis among Secondary School Students in Jalingo Town, Jalingo Local Government Area, Taraba State

This study was carried out to determine the prevalence of urinary Schistosomiasis among secondary school students in Jalingo town, Jalingo local government area, Nigeria. Ordinary centrifugal sedimentation technique was used and the deposits were examined microscopically. Data collected were analyzed using chi square. Out of the 200 samples examined, 37 (18.5%) had infection, with no significant difference (p>0.05) in infection rates between males (21.1%) and females (15.1%). Among the two schools sampled School A had the highest prevalence (22.0%) followed by School B (15.0%) with no significant difference (p>0.05). Children aged 9-12 years (60.0%) were more infected than those aged 19-21 (13.0%) (p<0.05).There was a close relationship between haematuria and positive urine samples as 72.7% of the students tested positive excreted blood in their urine (p<0.05). Major risk factors were poor hygiene, ignorance and poverty. The results of this study show that secondary school students harbor infection and are a source of transmission of Schistosomiasis in the study area. Planning and provision of drugs for treatment should be considered in disease prevention and control programmes. Community participatory health education should be encouraged as the first step in reducing infection and transmission of the disease.

Focal persistence of soil-transmitted helminthiases in impoverished areas in the State of Piaui, Northeastern Brazil.

ABSTRACTThis study aims to describe the prevalence, distribution, and factors associated with soil-transmitted helminthiases (STHs) in rural localities in Piaui, Brazil. Two cross-sectional surveys (n=605 subjects; 172 families) were carried out in order to obtain socio-demographic, anthropometric, spatial and parasitological data. Parasites were evaluated using Kato-Katz and centrifugal sedimentation techniques. Eggs were measured to assess infection with zoonotic Strongylida parasites. Kernel maps were constructed with Q-GIS. The prevalence of hookworm infection was 12.4% (75/605). Other helminthes found were Trichuris trichiura (n=1; 0.2%) and Hymenolepis nana (n=1; 0.2%). The hookworm positivity rate was significantly lower among subjects who had used albendazole when compared with individuals who had not used anthelmintics or had used antiprotozoal drugs in the last 6 months (8/134 [6.0%] vs. 59/415 [14.2%]; p=0.009). A total of 39/172 (22.7%) families had at least one infected member. The association between the number of dwellers and hookworm positivity in the family was present in a logistic regression multivariate model. Assessment of worm burdens showed 92.2% light, 6.2% moderate, and 1.6% heavy infections. Hookworm eggs (n=34) measured 57.2 - 75.4 µm in length and 36.4 - 44.2 µm in width (mean ± SD = 65.86 ± 4.66 µm L and 40.05 ± 1.99 µm W), commensurate with human hookworms. Hotspots suggest that transmission has a focal pattern. STHs persist in impoverished rural areas in Northeastern Brazil where currently available control strategies (mass drug administration) apparently do not allow the elimination of the infection.

Applicability of FLOTAC® technique in recovering equine strongyle larvae in the pasture: A comparison study

The FLOTAC® technique represents a highly sensitive method for the isolation of oocysts, eggs, and larvae of parasites in faeces. This assay could be used for detecting free-living stages of nematodes in the pasture but no attempt has been assessed so far. Therefore, the performance of FLOTAC® technique for isolating infective larvae of nematodes in the environment was investigated and compared with the spontaneous sedimentation (SST) and centrifugal sedimentation (CST) techniques. The study was conducted in a horse farm located in northeastern Brazil, where the occurrence of strongyle larvae had been previously reported. Pasture samplings were collected monthly from January to May 2016 in a 376 m2 crop area harvested with the Guinea grass Panicum cultivar Massai. The recovery of third-stage larvae (L3) was performed using the FLOTAC®, SST and CST techniques. Values of Cohen's kappa coefficient, sensitivity, specificity, positive and negative predictive values, and accuracy of each technique were assessed. Although strongyle larvae were evenly detected, with the FLOTAC® technique yielded the highest number of positive samples (i.e., 41%, 41/100, p < .0001). The main parasites isolated belonged to the Cyathostominae and Strongylinae subfamilies. Based on these results, the FLOTAC® technique should be considered as practical and safe method for the isolation of nematode larvae in the pasture, thus opening a new potential use for this tool in the field.

The influence of flaxseed gum on the microrheological properties and physicochemical stability of whey protein stabilized β-carotene emulsions.

The impact of flaxseed gum (FG) on the microrheological properties and physicochemical stability of whey protein isolate (WPI) stabilized β-carotene emulsions at pH 3.0 was studied. A layer-by-layer electrostatic deposition method was used to prepare multilayered β-carotene emulsions with interfacial membranes consisting of WPI and FG. The microrheological behavior of the multilayered β-carotene emulsions was measured through the diffusive wave spectroscopy technique. WPI alone and WPI-FG (concentration of FG = 0.1, 0.2, 0.3 wt%) stabilized β-carotene emulsions were purely viscous giving a mean square displacement that scaled linearly with decorrelation time (τ). The presence of 0.01, 0.02, and 0.05 wt% FG in the WPI-stabilized emulsions caused them to exhibit viscoelastic properties. Meanwhile, the increase in τ reflected the increase in the length scale of connectivity in the emulsions until a "cluster" was formed and the droplets were not free to move due to droplet-network interaction. The apparent increase in the macroscopic viscosity and elasticity index and decrease in the solid lipid balance and fluidity index of emulsions with lower concentrations (0.01, 0.02, 0.05 wt%) of FG indicated that the bridging flocculation of FG had a much more appreciable influence on the microrheological properties than depletion flocculation (higher concentrations, 0.1, 0.2, 0.3 wt%). Droplet size, zeta-potential, and transmission profiles using the centrifugal sedimentation technique and β-carotene degradation during storage were also characterized. With the addition of FG, the zeta-potential of WPI coated β-carotene droplets decreased from positive to negative, and an increase in the apparent droplet size was also noted. LUMISizer analysis exhibited an improvement in physical stability with the addition of 0.1 wt% FG. FG also helped to chemically stabilize the WPI emulsions against β-carotene degradation mainly by slowing down the mobility of the droplets.

Concordance between the zinc sulphate flotation and centrifugal sedimentation methods for the diagnosis of intestinal parasites

The diagnosis of intestinal parasitic infections depends on the parasite load, the specific gravity density of the parasite eggs, oocysts or cysts, and the density and viscosity of flotation or sedimentation medium where faeces are processed. To evaluate the concordance between zinc sulphate flotation and centrifugal sedimentation in the recovery of parasites in faecal samples of children. Faecal samples of 330 children from day care centers were evaluated by zinc sulphate flotation and centrifugal sedimentation techniques. The frequencies of detection of parasites by each method were determined and the agreement between the diagnostic techniques was evaluated using the kappa index, with 95% confidence intervals. The faecal flotation in zinc sulphate diagnosed significantly more cases of Trichuris trichiura infection when compared to centrifugal sedimentation (39/330; 11.8% vs. 13/330; 3.9%, p<0.001), with low diagnostic concordance between methods (kappa=0.264; 95% CI: 0.102-0.427). Moreover, all positive samples for Enterobius vermicularis eggs (n=5) and Strongyloides stercoralis larvae (n=3) were diagnosed only by zinc sulphate. No statistical differences were observed between methods for protozoa identification. The results showed that centrifugal flotation in zinc sulphate solution was significantly more likely to detect light helminths eggs such as those of T. trichiura and E. vermicularis in faeces than the centrifugal sedimentation process.

Physicochemical characterisation of β-carotene emulsion stabilised by covalent complexes of α-lactalbumin with (−)-epigallocatechin gallate or chlorogenic acid

In this study the impact of covalent complexes of α-lactalbumin (α-La) with (−)-epigallocatechin gallate (EGCG) or chlorogenic acid (CA) was investigated on the physicochemical properties of β-carotene oil-in-water emulsions. EGCG, or CA, was covalently linked to α-La at pH 8.0, as evidenced by increased total phenolic content and declined fluorescence intensity. Compared with those stabilised by α-La alone and α-La–CA or EGCG mixture, the emulsion stabilised by the α-La–EGCG covalent complex exhibited the least changes in particle size and transmission profiles, using a novel centrifugal sedimentation technique, indicating an improvement in the physical stability. The least degradation of β-carotene occurred in the emulsion stabilised with the α-La–EGCG covalent complex when stored at 25°C. These results implied that protein–polyphenol covalent complexes were able to enhance the physical stability of β-carotene emulsion and inhibit the degradation of β-carotene in oil-in-water emulsion, and the effect was influenced by the types of the phenolic compounds.

Common gastrointestinal parasites of indigenous camels (Camelus dromedarius) with traditional husbandry management (free-ranging system) in central deserts of Iran

Gastrointestinal parasites of domesticated animals, especially in animals with traditional husbandry management cause reduction in production and performance of them. Aim of our study was to determine prevalence of gastrointestinal parasites in indigenous camels, with traditional husbandry management that have no direct contact with other livestock. This study was carried out between Kerman and Yazd provinces of Iran, midsummer 2011. Fecal samples of 100 randomly selected camels of all age and sex, collected directly from their rectum. The fecal samples were examined by direct smear, simple flotation technique, centrifugal sedimentation technique, and McMaster egg counting technique and fecal culture to identification and determine the burden of parasites in different age groups. Nematode eggs and Eimeria oocysts were found (64%) and (24%) in fecal samples respectively. Parasite eggs that observed in camel feces were belong to Nematodirus spp. (52%), Trichostrongyle type eggs (49%), Haemonchus spp. (38%), Trichuris spp. (14%) Marshallagia spp. (10%) and Eimeria cameli (24%), the age of infected camels with helminthic infections was significantly higher than non-infected camels (p<0.05), there was also a significant correlation between age and severity of coccidiosis (p<0.05). Camel calves and camels below 5years old were more infected with the Eimeria sp. than older ones. This study revealed gastrointestinal parasites is a major problem of indigenous camels with traditional husbandry, so parasite control programs must be established for increasing the productivity of this useful animal and industrial system for breeding camels recommended to increase productivity of them, especially where harsh climatic condition affected other livestock.

Prevalence of Schistosomiasis among Secondary School Boarding Students in Potiskum Metropolis, Yobe State, North-Eastern Nigeria

Schistosomiasis remains one of the world&#8217;s most prevalent diseases of public health importance. Despite more than a century of control efforts and the introduction of highly effective antischistosomal drug the eradication of the disease is still far from actualization. Six hundred (300 stool and300 urine) samples were collected randomly from the students who consented after obtaining some vital demographic data from them. The stool samples were processed using formol ether concentration techniques while the urine samples were processed by ordinary centrifugal sedimentation technique. The result obtained was tested using Chi-square. Of 600 samples, 30 urine samples were positive for S.haematobium giving 10.0% urinary schistosomiasis, while 6 faecal samples were positive for S. mansoni giving 2.0% intestinal schistosomiasis and an overall 6.0% of schistosomiasis.The result indicates that there is an increase in prevalence with increase in age. The infection rate was significantly higher (p &lt; 0.05) among males (8.5%) than among females (1.0%).Infection was higher (11.2%) among students whose normal source of drinking water is stream, followed by those whose source of drinking water is well (4.0%) and the least among those using tap water (2.2%). The prevalence of schistosomiasis in relation to schools indicates a significant relationship (p &lt; 0.05).FGSS had the highest prevalence (11.5%), followed by GSSTSS with 5.5% and GGSS recorded the least with 1.0%. Lack of prompt diagnosis, inadequate knowledge on the causes of schistosomiasis, unsuitable water supply and exposure to water bodies may be the likely predisposing factors responsible for the prevalence rate recorded in the study area.

Impact of whey protein – Beet pectin conjugation on the physicochemical stability of β-carotene emulsions

The aim of the present study was to investigate the impact of whey protein isolate (WPI)-beet pectin conjugation on the physical and chemical properties of oil-in-water emulsions incorporating β-carotene within the oil droplets. Covalent coupling of WPI to beet pectin was achieved by dry heating of WPI-beet pectin mixtures of different weight ratios at 80, 90, 100 °C and 79% relative humidity for incubation times ranging from 1 to 9 h. It was confirmed by SDS-polyacrylamide gel electrophoresis that WPI covalently linked to beet pectin. The physical and chemical stability of β-carotene emulsions was characterized by droplet size and distribution, transmission profiles using novel centrifugal sedimentation technique, microstructure and β-carotene degradation during the storage. Compared with those stabilized by WPI alone and unheated WPI-beet pectin mixtures, β-carotene emulsions stabilized by WPI-beet pectin conjugates had much smaller droplet sizes, more homogenous droplet size distribution, less change in centrifugal transmission profiles and obviously improved freeze–thaw stability, indicating a very substantial improvement in the physical stability. Rheological analysis exhibited that emulsions stabilized by WPI-beet pectin conjugates changed from a shear thinning to more like Newtonian liquid compared those with WPI alone and unheated WPI-beet pectin mixtures. Degradation of β-carotene in emulsion during storage was more obviously retarded by WPI-beet pectin conjugate than WPI and unheated WPI-beet pectin mixture, probably due to a thicker and denser interfacial layer in emulsion droplets. These results implied that protein–polysaccharide conjugates were able to improve the physical stability of β-carotene emulsion and inhibit the deterioration of β-carotene in oil-in-water emulsions.

Impact of High Hydrostatic Pressure on the Emulsifying Properties of Whey Protein Isolate–Chitosan Mixtures

The influence of high hydrostatic pressure (HHP) on the emulsifying properties of whey protein isolate (WPI) and chitosan mixtures in sunflower oil-in-water emulsion has been investigated at pH 4.0. WPI and chitosan mixtures at various ratios were treated at pressure levels in the range of 0–600 MPa for 10–30 min. The emulsifying properties of the mixtures were analyzed by dynamic light scattering and a centrifugal sedimentation technique. HHP treatments of the mixtures resulted in improvement in their emulsifying properties, with the emulsions formed showing more than threefold reductions in droplet size, much more homogeneous droplet distribution, and better creaming stability. The higher the treatment pressure was, the smaller the droplet size and more stable the emulsions were, with those prepared with the mixtures treated at 600 MPa showing no noticeable creaming after 30 days of storage at ambient temperature. The ratio of WPI to chitosan and treatment time also affected the emulsification stability of the mixtures, with a WPI to chitosan ratio of 1:4 (w/w) and treatment time of 20 min found to be the optimum conditions. These results showed that HHP could be a useful method for enhancing the emulsifying properties of protein–polysaccharide mixtures.

Prevalence of urinary schistosomiasis in Comboni and Toklokpo Junior High Schools (JHS) at Sogakope

Schistosomiasis remains an important parasitic disease worldwide. The level of prevalence of schistosomiasis in the Sogakope district is essentially due to the frequent exposure of the inhabitants to water bodies such as the Lake Volta and other lakes. This research investigated the prevalence of schistosomiasis in Toklokpo (about two kilometres from the bank of the Volta River) and Comboni (situated along the bank of the river Volta) in the Sogakope district. A total of 150 samples of urine were taken: Seventy-five from Toklokpo JHS and 75 from Comboni JHS. Each of the 75 samples was selected randomly from boys and girls. The urine samples were processed by the centrifugal sedimentation technique. The total prevalence of urinary schistosomiasis in the study area was 26%. The prevalence rates of urinary schistosomiasis in the two schools were 12.6% and 13.3% for Comboni JHS and Toklokpo JHS respectively. The highest prevalence occurred in the males between 10-11 years age group. For both sexes, Toklokpo Junior High School recorded higher prevalence of the disease numerically .It is recommended that urgent measure is taken to curb the menace.doi: 10.4314/ajcem.v12i3.5

Improving the breakdown strength of rutile capacitor by gelcasting

Gelcasting, one of the colloidal in-situ forming techniques, has been highly concerned and utilized in the forming of many sorts of ceramic material systems [1–3], for homogeneous microstructures of bodies can be assured by this low-cost and near-net-shape molding process [4–8]. Thus the parts exhibit good mechanical performances and high reliability [9, 10]. Because of high power and large breakdown strength, rutile capacitors have been widely used in high frequency appliances such as broadcast emitters, radars, high frequency welding machines and smelting furnaces. There are more than one hundred kinds of such products with various sizes and complex shapes. In the past decades, rutile capacitors with complex shape and large size were made by extrusion forming and then machining. First, the rutile mixture with a definite composition obtained by ball-milling, was filtered one day, aged for one month, and mixed in vacuum. Second, after extruded, cylindric green bodies were rolled, and dried for more than two weeks. Next, by means of machining, the green bodies possessed a desired complex shape. Finally, through sintering and some sequent process, the high power rutile capacitor can be prepared. The whole procedure needed two and a half months, and the machining of dried green bodies resulted in a great deal of environment pollution and waste of starting materials. Furthermore, in the traditional process of high power rutile capacitors, a bottleneck, which results from the large size, complex shape and many kinds of components in raw materials, greatly impairs their functional properties, so the breakdown strength by this process generally reached only 15 KV/mm. A new route for preparing rutile capacitors by gelcasting, as indicated in Fig. 1, has been developed. By this route, not only can the production cycle be decreased to three weeks, but also the dust pollution caused by machining can be eliminated due to the insitu forming. Thus the production cost can be reduced and the environment can also be improved. And particularly, the breakdown voltage is improved from original 15 KV/mm to more than 22 KV/mm. The composition of rutile capacitors is shown in Table I. The commercial rutile powder and additives are of industrial purity, from Shanghai, China. The following are used in our work: deionized water with conductivity of 1.02 μS·cm−1, acrylamide (AM) as monomer, methylenebisacrylamide (MBAM) as crosslinker, (NH4)2S2O8 as initiator, N,N,N′,N′tetraethylmethylenediamine (TEMED) as catalyst and PMAA-NH4 as dispersant. The rutile mixture was pre-calcined at 900 ◦C and then ball-milled for 50 h. The particle size distribution measured by an X-ray centrifugal sedimentation technique (Instrument type: BI-XDC, made in Brookhaven Instrument Co., USA) is shown in Fig. 2. The volume moment mean diameter was 1.8 μm. A concentrated 53 vol% rutile suspension with low viscosity was successfully prepared. The apparent viscosity was measured by rotating viscometer (model NSX-11, Chengdu Instrument Plant, People’s Republic of China). Microstructures of sintered bodies were observed by S450 SEM from Hitachi of Japan. The rutile mixture pre-calcined was well dispersed in premixed solution made up of acrylamide, deionized water, and N,N′-methylenbisacrylamide in the aid of a PMAA-NH4, after ball-milling 50 h. It can be seen from Fig. 3 that the apparent viscosity strikingly decreased

Cryptosporidium muris in dairy cattle in Brazil

A total of 580 fecal samples from 30 cows and their calves from three dairy farms in São Paulo State, Brazil, was collected monthly over a period of 1 year (April 1994 to March 1995). A combination of water-ether centrifugal sedimentation technique followed by sucrose centrifugal flotation was used for neonatal samples and sucrose centrifugal flotation for the remainder of the samples. Cryptosporidium muris was found in calves from all farms, although the parasite was not detected in the dams. C. muris oocysts were excreted by 14 of the 30 calves, on at least one occasion during the year. Of the 307 calf fecal samples examined, 53 (17.3%) were positive for C. muris. The mean persistency of oocyst shedding in feces was 4 ± 3 months. Sixty-four per cent of the positive calves excreted few oocysts, while 36% discharged many oocysts for a longer period (P < 0.05). Oocysts were first detected at the mean age of 3±1 months. The age of the positive calves ranged from 6 weeks to 14 months.

Status of intestinal parasitic infections in a remote island, Yondo, Jeonranam-do: province.

This study was performed to observe the present status of intestinal parasitic infections in a remote island, Yondo, located in southern part of Jeonranam-do(province), Korea. In February and May 1988, total 1,011 individual stool samples were collected and examined for intestinal helminths and protozoa using formalin-ether centrifugal sedimentation technique. The results are summarized as follows: Of 1,011 ingabitants examined, 398(39.4%) were positive for intestinal parasites. Helminth positives were 372(36.8%), and protozoan cyst positives were 56(5.5%). Ten species of parasites were found. Trichuris trichiura revealed the highest infection rate of 27.5%, Ascaris lumbricoides 17.4%, Taenia sp. 5.8%, Entamoeba coli 3.3%, Giardia lamblia 1.5%, Endolimax nana 0.8%, Hymenolepis nana 0.4%, hookworm 0.2%, Trichostrongylus orientalis 0.2%, and Entamoeba histolytica 0.2%, respectively. The female group showed higher positive rate (44.0%) than males (34.7%). Also, higher positive rates were observed among adults as compared with the group younger than 10 years old. Average value of E.P.G. was 1,876(range 200-17,800) in A. lumbricoides positives, and 327(range 200-1,600) in T. trichiura positive cases. In helminth egg positive cases, single infection was 63.4%, double infection 34.7%, and triple infection 1.9%, respectively. Among protozoan cyst positives, single infection was 94.6%, and double infection was 5.4%. The present study revealed that the prevalence of intestinal parasites among inhabitants in Yondo island is still so high that special control measures should be performed.

Size and Density of Protein Inclusion Bodies

The size distribution and density of two types of protein inclusion bodies arising from the synthesis in E. coli of recombinant calf prochymosin and γ–interferon were examined. A combination of electrical sensing zone and centrifugal sedimentation techniques were used to characterize the particles. The mean size and standard deviation (sd) of the distributions for the γ–interferon and prochymosin–based inclusion bodies were 0.81 μm, sd 0.17 μm, and 1.28 μm, sd 0.46 μm, respectively. Sedimentation studies indicated that the density of the protein inclusion bodies increases with the density of the suspending solvent. These density variations are consistent with the bodies having a voidage, accessible to the suspending fluid of 70% (γ–interferon) and 85% (prochymosin) of the total volume.