Elucidation of the life cycle of the intestinal protozoan Blastocystis hominis

This paper elucidates the status of the different morphological forms of Blastocystis and reports the existence of thin- and thick-walled cysts in B. hominis on the basis of current experimental evidence. It is suggested that the thin-walled cysts are autoinfectious, leading to multiplication of the organism in the intestinal tract. The thick-walled cysts are responsible for external transmission via the faecal-oral route. A life cycle for B. hominis is postulated on the basis of these findings.

Augmentation of murine natural killer cell and antibody dependent cellular cytotoxicity activities by Phyllanthus emblica, a new immunomodulator

When administered orally, Phyllanthus emblica, an excellent source of vitamin C (ascorbate), has been found to enhance natural killer (NK) cell activity and antibody dependent cellular cytotoxicity (ADCC) in syngeneic BALB/c mice, bearing Dalton's lymphoma ascites (DLA) tumor. P. emblica elicited a 2-fold increase in splenic NK cell activity on day 3 post tumor inoculation. Enhanced activity was highly significant on days 3, 5, 7 and 9 after tumor inoculation with respect to the untreated tumor bearing control. A significant enhancement in ADCC was documented on days 3, 7, 9, 11 and 13 in drug treated mice as compared to the control. An increase in life span (ILS) of 35% was recorded in tumor bearing mice treated with P. emblica. This increased survival was completely abrogated when NK cell and killer (K) cell activities were depleted either by cyclophosphamide or anti-asialo-GM1 antibody treatment. These results indicate: (a) an absolute requirement for a functional NK cell or K cell population in order that P. emblica can exert its effect on tumor bearing animals, and (b) the antitumor activity of P. emblica is mediated primarily through the ability of the drug to augment natural cell mediated cytotoxicity.

Differentiation of the various stages of Blastocystis hominis by acridine orange staining

Acridine orange staining differentiates the cystic and the central body forms of Blastocystis hominis and offers a very convenient and easy method to observe the internal structure of the parasite. Acridine orange stains the nuclei and the central body of the rounded vacuolar forms of the parasite bright and dull green, respectively. The colour changes to yellow and then to flaming red-orange when the rounded central body forms of the parasite become cystic.

Ultrastructural changes during in vitro encystment of Blastocystis hominis

The morphological changes occurring in Blastocystis hominis at different time points following in vitro encystment were studied by electron microscopy. The following stages of the parasite were sequentially seen: (a) the amoebic form, which was irregular in shape, with a majority of the organelles being concentrated at the condensed cytoplasmic region; (b) the pre-cystic form, which was rounded and had an electron-dense material forming a homogeneous wall around the central body; and (c) the cystic form, which had a very prominent, thick osmiophilic electron-dense wall, within which there were many inclusions and possibly reproductive granules. The amoebic form appeared to be an intermediate stage between the vacuolar form and the pre-cystic form, as this stage allowed the parasite to ingest bacteria to enhance encystment. The pre-cystic stage had previously been shown in experimental infection to be infective. The role of the cystic stage in producing infection is currently being investigated.

Constant Scallop-height Machining of Free-form Surfaces

A novel approach for the NC tool-path generation of free-form surfaces is presented. Traditionally, the distance between adjacent tool-paths in either the Euclidean space or in the parametric space is kept constant. Instead, in this work, the scallop-height is kept constant. This leads to a significant reduction in the size of the CL (cutter location) data accompanied by a reduction in the machining time. This work focuses on the zig-zag (meander) finishing using a ball-end milling cutter.

Natural-killer-cell and antibody-dependent cellular cytotoxicity in gastric-carcinoma patients - modulatory effects of IL-2 and 5-Fluorouracil

Non-adherent peripheral blood mononuclear cells (PBMC) from 15 patients with carcinoma of the stomach and 6 normal healthy controls were assessed for natural killer cell mediated cytotoxicity (NKCMC) and antibody dependent cellular cytotoxicity (ADCC) in a 4 hour (51)Chromium release assay against target cells, K-562 and sensitized chicken red blood cells (CRBC), respectively. NKCMC and ADCC were significantly reduced in patients with respect to normal controls. However, significant enhancement in NKCMC and ADCC was observed when PBMC from patients were cultured in RPMI-1640 containing 200 IU/ml of Interleukin-2 (IL-2) for 4 days in 5% CO2 atmosphere at 37 degrees C. Augmentation of NKCMC and ADCC was also detected when a follow-up study of the patients was conducted after one month following initial trial of chemotherapy with 5-fluorouracil (5-Fu). Patients, who had undergone clinical trial with 5-Fu were better responders of IL-2 activation as reflected on NK cell and ADCC potential of these patients. Our investigations highlight the synergistic effect of 5-Fu and IL-2 on effecters of natural immunity in patients with carcinoma of the stomach, Judicious modulation of effecters may be beneficial in killing residual cancer cells in vivo.

A multiple fission-like mode of asexual reproduction in Blastocystis hominis

A non-axenic and an axenic isolate of Blastocystis hominis have been induced to form cysts in vitro using an encystation medium. The morphology of the parasite at different time points was observed by scanning electron microscopy. In day-2 cultures the cysts were spherical and had a non-uniform, coarse outer surface around the body. A deep, pore-like opening was seen in some of the parasites. Most of the cysts from day-4 and day-6 cultures ruptured, revealing small, uniformly sized spherical bodies occurring in grape-like clusters. Acridine orange staining confirmed that these bodies were the progeny of Blastocystis hominis. A multiple fission-like reproduction process giving rise to many daughter Blastocystis occurs within the cyst.

Gliclazide in the treatment of obese non-insulin dependent diabetic patients

The clinical efficacy of gliclazide and its effect on plasma glucose, body weight and serum lipids was assessed in a 3 months open trial of 30 obese, Non-Insulin Dependent diabetes mellitus (NIDDM) patients who failed to respond to diet therapy alone. By day 20, the mean post prandial plasma glucose (PPG), and fasting plasma glucose (FPG) were significantly reduced from 276 +/- 13.5 to 195.8 +/- 13.9 mg % (p < 0.01) and 179 +/- 9.3 to 130.6 +/- 9.6 mg % (p < 0.01) respectively. This early glycaemic control was maintained, and by 3 months a further significant decrease occurred in PPG to 156.46 +/- 7.6 mg % (p < 0.01), and FPG to 106.9 +/- 3.8 mg % (p < 0.01). Mean glycosylated haemoglobin (HbA1c) was reduced from 10.3% to 7.7%. The drug had a favourable effect on serum lipids, significantly increasing high density lipoprotein fraction of cholesterol (HDL-C) (p < 0.034), and decreasing low density lipoprotein fraction of cholesterol (LDL-C) (p < 0.049). Mean body weight showed a significant reduction of 1.5 kg (p < 0.003). We conclude that gliclazide is an effective hypoglycaemic agent that ensures a rapid and sustained blood glucose control with a favourable effect on lipids and body weight in obese NIDDM patients.

In vitro encystment and experimental infections of Blastocystis hominis

Cultures of Blastocystis hominis were induced to encyst using three encystation media: (a) an encystation medium (EM) comprising yeast extract in buffered saline containing 50% horse serum, (b) an encystation medium (CEM) comprising EM conditioned with bacterial soluble products and (c) an encystation medium (TEM) containing 0.5% trypticase in EM. Two isolates of B. hominis were studied, an axenized isolate C and a non-axenized isolate MS. In EM, isolate C did not encyst, whereas 6.1% of isolate MS had encysted by day 1. However, in CEM and TEM, 17.4% and 25.7% of isolate C, respectively, had encysted by day 5. In all three media, isolate MS encysted more readily than isolate C, with as much as 91.7% of the former encysting in TEM. As viewed by phase-contrast microscopy, cyst-like stages appeared highly refractile. Direct stool examination of juvenile Wistar rats infected with 10,000 cyst-like stages of both C and MS isolates showed Blastocystis at day 2 post-infection. At autopsy on day 7, large numbers of Blastocystis were seen in the cecum, with smaller numbers being observed in the large intestine. In contrast, rats fed with various inocula of the vacuolar stages of isolates C and MS did not become infected, indicating the importance of the encysted stages in the transmission of the parasite.

Long term maintenance of Toxoplasma gondii (Rh strain) in Vero cell line and use of harvested antigens for immunodiagnosis

Thirty in vitro serial passages of Toxoplasman gondii cultures in Vero cell line performed once in every five days had a mean increase in parasite count of 74.4 +/- 14.8 times from that of initial counts. Long term cultures in Vero cell line did not alter the virulence of the parasite. The good correlation (r = 0.99) between the IFA titer and ELISA OD values using the parasite antigens from in vitro sources indicates that long term maintenance of T. gondii in culture does not affect significantly the ability to recognize antibodies to surface and soluble antigens. The results also show that soluble antigens containing host cells can be directly used for immunodiagnostic purposes without purification. The in vitro maintenance of T. gondii is safer and cheaper when compared to the in vivo method.

A comparative study of X-ray pelvimetry and CT pelvimetry

In this study 24 patients who had conventional erect lateral X-ray pelvimetry had a CT pelvimetry done after delivery to complete the pelvimetry views. The erect lateral pelvimetry was read independently by a Consultant Radiologist, Consultant Obstetrician and a Medical Officer training in Obstetrics and Gynaecology. Using CT pelvimetry as the 'gold standard' (as the error of measurement was known with the machine used) the 3 readings were compared. There was no statistical difference in the values suggesting that X-ray pelvimetry is comparable to CT pelvimetry. However CT pelvimetry is preferred, if available, because of the lower dose of radiation involved, more comfort for the patient and shorter time in performing the procedure. Measurements done are easily read directly from the CT console.

Antifilarial activity of intravenous suramin and oral diethylcarbamazine citrate on subperiodic Brugia malayi in the leaf-monkey, Presbytis cristata

The known filaricides, suramin and diethylcarbamazine citrate, were tested against subperiodic Brugia malayi infection in the leaf-monkey, Presbytis cristata. As expected, intravenous suramin at 10 mg/kg daily x 5 days or 17 mg/kg weekly x 5 weeks, did not show any microfilaricidal activity, but substantially reduced the recovery of live adult worms to 50.6% and 13.6% of controls respectively. Oral diethylcarbamazine citrate at 6 mg/kg daily x 6 or 10 days reduced final microfilarial counts to 30% of initial counts four weeks post-treatment and adult worm recovery was reduced to 4.5% and 0% of controls respectively. Although the antifilarial activity of these drugs against the infection in this non-human primate model appears to be similar to that seen in man, these results have to be confirmed using larger groups of animals.

Complete heart block in rheumatoid arthritis

A case of rheumatoid arthritis with complete AV heart block is reported. The relevant literature is briefly reviewed.

Experimental infection of the leaf-monkeys, Presbytis cristata and Presbytis melalophos with subperiodic Brugia malayi

The leaf-monkeys, Presbytis cristata and Presbytis melalophos, experimentally infected with subperiodic Brugia malayi, have been used for studies on the pathoimmunology of the infection and the screening of potential filaricides during the last 6-8 years, and considerable information on the pattern of microfilaraemia and adult worm recoveries have been obtained. The prepatent periods in 97 P. cristata and 45 P. melalophos, each infected with about 200 infective larvae, were similar, these being approximately 70 and 68 days respectively. Although all infected animals became microfilaraemic, the peak geometric mean count was much higher in P. cristata than in P. melalophos, this being 182.0 and 65.8 per ml blood respectively. Mean adult worm recovery expressed as the percentage of the infective dose was 4.7% and 2.5%, respectively. Most worms were recovered from the sacral nodes/thoracic duct or inguinal lymph nodes in these animals. In view of the higher worm recovery and the higher peak microfilaraemia attained, it is concluded that P. cristata is a better model for the infection than P. melalophos.

Number and types of hemocytes in Sunetta scripta and Villorita cyprinoides var. cochinensis (Bivalvia), and leukocytosis subsequent to bacterial challenge

The number and types of hemocytes in four size groups of the clam species Sunetta scripta and Villorita cyprinoides var. cochinensis, and leukocytosis in the 38- to 40-mm-size-group clams of both species subsequent to challenge with Vibrio alginolyticus at a concentration of 1 x 10(8) cells/0.02 ml of sterile 2% saline was investigated. In S. scripta, the mean total hemocyte count in the 42- to 44-mm size group was significantly lower than that of the three other size groups but there was no significant variation in total cell counts in the four size groups of V. cyprinoides var. cochinensis. Only two types of hemocytes, granulocytes and agranulocytes, occur and the percentage of agranulocytes was roughly half of that of granulocytes. The data on the effects of sham injection and Vibrio injection suggest that there is significant leukocytosis early in both clam species as a result of sham injection; the bacterial challenge produces significant leukocytosis in V. cyprinoides var. cochinensis both early (6 and 12 hr) and later (48,96 and 120 hr), but only at 48 hr in S. scripta; and in both clam species there is significant increase in total cell counts in Vibrio-injected ones than in untampered controls at various time intervals.