Continuous cultivation of intraerythrocytic Plasmodium falciparum in a serum-free medium with the use of a growth-promoting factor

Serum-free media were used to culture Plasmodium falciparum. A commercial preparation, Daigo's GF21 developed as a growth-promoting factor for many kinds of mammalian cells, and consisting of the 55-70% ammonium sulphate fraction of adult bovine serum, insulin, transferrin, ethanolamine and sodium selenite, was found to sustain growth of the parasite when Daigo's T was employed as a basal medium. The optimal Daigo's GF21 concentration for parasite growth was between 5 and 20% (v/v), with the best results at 10%. Differential counts indicated that Daigo's GF21 is essential for schizogony. Established serum-free medium, GIT, consisting of Daigo's T basal medium and Daigo's GF21, yielded good parasite growth without any supplementation. Growth-promoting factor derived from adult bovine serum in Daigo's GF21 was shown to be crucial to parasite growth. The results presented here will not only be of practical value, but will provide important information about the developmental requirements for the parasite.

[Changes of cytokine levels in ascitic fluid after intraperitoneal administration of OK-432 or CDDP]

In order to evaluate the biological response after intraperitoneal administration of OK-432 and CDDP, we studied the changes of cytokine levels in ascitic fluid. A total of 53 gastric cancer patients were included in this study. OK-432 20KE was administered in 7 patients and CDDP was administered in 4 patients intraperitoneally during operation. The IL-6, IL-8, TNF-alpha and sTNF RI levels in ascitic fluid were measured from 0 to 5 postoperative day. These results were compared with those obtained from the control groups (42 patients). The ascitic level of IL-6 increased immediately after operation, then gradually decreased. The elevations of IL-6 from 0 to 5 postoperative day were remarkably higher in the OK-432 treated group, and those on 0 and 1 postoperative days were remarkably lower in CDDP treated group than in the control group. Similarly, the ascitic level of IL-8 elevated soon after operation and then decreased gradually. In the OK-432 treated group, the ascitic level of IL-8 was significantly higher than in the control group from 0 to 2 postoperative day. Ascitic TNF-alpha was detectable only in the ascites soon after operation in the OK-432 treated group. The ascitic level of sTNF RI peaked on 2 postoperative day in the control and the OK-432 treated group and 1 postoperative day in the CDDP treated group. There were no significant differences between these groups.

Epidemiological survey of dementia and depression among the aged living in the community in Japan

The authors surveyed the prevalence of depression and dementia in the elderly in Ohira town in Japan from 1989 to 1990. The total population of this town was 26,712, with 2,778 people aged 65 and above, constituting 10.4% of the total population. The prevalence of dementia (n = 128) was 6.1% and that of major depression (n = 9) was 0.4%, according to the DSM-III-R criteria. The prevalence of a depressive state which did not fulfill the criteria for major depression (n = 55) was 2.4%. The patients with multi-infarct dementia (n = 49) suffered from depression (42.8%) more frequently than those with dementia of the Alzheimer type (11.1%). The rate of depression coexisting with dementia increased with aging, while the rate of depression without dementia did not change in all the age groups.

Arginine-dependent generation of reactive nitrogen intermediates is instrumental in the in vitro killing of protoscoleces of Echinococcus multilocularis by activated macrophages

The interaction between protoscoleces of Echinococcus multilocularis and activated murine macrophages was examined in this study. Marked protoscolicidal activity was displayed by peritoneal macrophages (PM) activated with interferon-gamma (IFN-gamma), or IFN-gamma plus lipopolysaccharide. Pretreatment of the parasites with heat-inactivated specific murine infection serum, but not with normal serum rendered them more susceptible to PM killing. NG-monomethyl-L-arginine, a competitive inhibitor of L-arginine completely inhibited the killing activity of activated PM, while reconstitution of arginine-free medium with L-arginine restored the killing properties of the activated PM. The results show that activated PM have the ability to kill E. multilocularis protoscoleces in vitro and suggest that reactive nitrogen intermediates (RNI) play an important role in the mechanism. An oxygen-mediated mechanism did not appear to play a role because scavengers of reactive oxygen species did not reduce the killing activity. The arginine-dependent killing mechanism was enhanced by superoxide dismutase (SOD), probably because SOD might prolong the effect of nitric oxide. Secretion of RNI by activated macrophages may be capable of a significant role in preventing of the dissemination of E. multilocularis infection in vivo.

[Changes in cytokine levels in ascitic fluid after intraperitoneal administration of OK-432]

In order to evaluate the biological response after intraperitoneal administration of OK-432, we studied the changes of cytokine levels in ascitic fluid. In 6 advanced gastric cancer patients with peritoneal dissemination or extensive lymph node metastases, OK-432 20 KE was administered intraperitoneally during operation and the IL-6, IL-8 and IFN-gamma levels in ascitic fluid were measured from 0 to 5 postoperative days. These results were compared with those obtained from non-OK-432 administered control groups (17 cases). The ascitic level of IL-8 increased immediately after operation and gradually decreased. In the OK-432 treated group, the elevation of IL-8 on 0 and 1 postoperative days was remarkable, and there were statistically significant differences with the control group. Similarly, the ascitic level of IL-6 elevated soon after operation and then decreased gradually. In the OK-432 treated group, the ascitic level of IL-6 was significantly higher than in the control group after 3 postoperative days. There were no differences in changes of ascitic IFN-gamma levels between the groups. From these results, IL-6 and IL-8 appeared to be induced in ascitic fluid by intraperitoneal administration of OK-432.

[Role of oxygen radicals in the pathogenesis of acute gastric mucosal lesion under obstructive jaundice]

In this study we examined the role of oxygen-derived free radicals in the pathogenesis of acute gastric mucosal lesion induced by obstructive jaundice in rats. Rats were divided into 4 groups as follows: control (sham operation), jaundiced (ligation and dissection of bile duct), vagotomized (truncal vagotomy), and vagotomized with jaundice group. The water immersion restraint procedure was performed. The water immersion restraint procedure was performed. The results obtained are as follows: jaundiced group showed significant increase of ulcer index (UI) and significant decrease of gastric mucosal blood flow (GMBF) and gastric mucosal potential difference (PD). However, intragastric pH (pH) was unchanged compared to the control group. Oxygen radical generating system (gastric mucosal XOD activity and thiobarbiturate acid) and oxygen radical scavenging system (gastric mucosal SOD activity and GSH-px activity) were higher than those of control group. Vagotomized group showed significant increase of pH compared to the control group. Oxygen generating system and scavenging system were unchanged compared to the control group. Vagotomized with jaundice group showed depression of UI and improvement of oxygen radical generating system and scavenging system. However GMBF, PD nad pH were unchanged compared to the jaundiced group. These results suggest that oxygen radical play some role in the development of acute gastric mucosal lesion induced by obstructive jaundice.

Regulation of the human T-cell response to Schistosoma japonicum egg antigen by concomitant cellular and humoral mechanisms in vitro

Serum-mediated regulation of T-cell responses specific for soluble egg antigen (SEA) of Schistosoma japonicum was tested in human hosts. When we added autologous serum to SEA-specific human T-cell lines (CD3+, 4+, 8-), we observed suppression of T-cell proliferation, and this suppressive activity was detected in the immunoglobulin-G2 (IgG2) subclass. Suppression was dose-dependent and antigen-specific. T-cell proliferation induced by only one SEA fraction of greater than 18 kDa was modulated in the presence of 100 micrograms/ml autologous as well as allogeneic infected IgG2. This SEA fraction-driven proliferation was also regulated by suppressor T-cells through distinct suppressive mechanisms. Our results suggest that T-cell responses to a particular component(s) of SEA are strictly regulated through both cellular and humoral mechanisms in human chronic S. japonicum infection.

Biological nature of Cryptosporidium sp. isolated from a cat

A small type of Cryptosporidium oocysts was isolated from a naturally infected cat and its biological nature was investigated. In cats experimentally inoculated with Cryptosporidium oocysts, long-lasting shedding of the oocysts occurred after a prepatent period of 8-10 days, and a number of peaks of oocyst count appeared at intervals of several days to a few weeks, earlier in the infection course. Cryptosporidium infection in cats is likely to pass from an acute to a chronic stage. During the chronic stage, prednisolone injection into the cats gave rise to a recurrence of proliferation of the parasite along with a marked increase in the number of oocysts shed. None of the infected cats showed clinical symptoms. Infection experiments using Cryptosporidium oocysts were unsuccessful in several species of animals such as mice, rats, guinea pigs, dogs, suckling mice and mice previously injected with prednisolone or hydrocortisone.

Prevalence of Cryptosporidium infection among domestic cats in the Tokyo Metropolitan District, Japan

From February, 1988 to February, 1989, an epidemiological survey for feline cryptosporidiosis was carried out on domestic cats that had been committed to the Tokyo Metropolitan Animal Protection Center by owners residing in the Tokyo Metropolitan District. Of a total of 608 cats, 23 (3.8%) were found to have Cryptosporidium oocysts. The percentage of cats positive for the infection ranged from 0 to 13.6% by month. The infection was found to be more common in "baby" and "young" cats than in "middle" and "old" ones. No significant difference in incidence was shown between the sexes. In each positive cat, no apparent clinical symptom such as diarrhea was found, and the size of the oocysts measured from 4.3 to 4.7 microns in diameter (small type).

A simple staining method for cryptosporidian oocysts and sporozoites

A useful staining method for detection of cryptosporidian oocysts and sporozoites was developed and described. The modified Kohn's one-step staining technique with an additional modification, i.e., longer staining time and higher staining temperature than those originally described, was tested on fecal smears from cats infected with Cryptosporidium sp. By this improved staining procedure, the oocyst appeared as a slightly oval body containing four internal sporozoites colored blue to blue-gray. The oocyst wall was stained dark green to black. The morphological feature of the oocyst was recognized much more clearly by this staining technique than by such currently used techniques as acid-fast and Giemsa staining. This staining procedure proved to be simple and less costly and to secure a good preservation.

Life cycle of Tritrichomonas muris

Morphological and physiological studies were carried out on a flagellate, Tritrichomonas muris, in golden hamsters. The experiments confirmed that a pseudocyst and an intermediate form exist in addition to the trophozoite in the life cycle; furthermore it was shown that the pseudocyst was the infective stage, and that a true cyst did not occur.

Recovery from immunesuppression in mice infected with Schistosoma japonicum by treatment of praziquantel

To learn the possible alteration of immune response, hemolytic plaque-forming cells (PFC) produced in the spleen of Schistosoma japonicum infected mice treated with Praziquantel and untreated group were counted. There was no significant difference in the immunesuppression percentage between the treated and untreated groups 1 and 3 weeks after treatment. In 5 weeks after treatment, however, the immunesuppression percentage in the treated mice was markedly reduced in comparison with that of the untreated group. Recovery from immunesuppression appears to be associated with elimination or impairment of adult worms.

Cytotoxic factors toward neuroblastoma cells in trypomastigotes of Trypanosoma cruzi

Homogenates of trypomastigotes of Trypanosoma cruzi (T.c) exhibited low-potency cytotoxic activity toward neuroblastoma cells. The cytotoxic activity was markedly decreased after preservation for 1 week, even at -20 degrees C. Trypsin and pronase E were shown to effectively enhance or restore the cytotoxic activity of T.c by producing some alteration in T.c, depending on concentrations of and treatment time with the enzymes. The cytotoxic factors were insoluble in saline and found in the chloroform extracts of a T.c homogenate. Analysis by thin-layer chromatography showed that the cytotoxic activity of T.c was found in the free fatty acids and lysophospholipids fractions. Of the free fatty acids present in T.c, eicosatetraenoic (20:4) and octadecadienoic (18:2) acids were the most cytotoxic. It was assumed that as much as 27.2% (w/w) of the total lipids of T.c consists of free fatty acids, and 1 mg of protein of the T.c homogenate contains 96 micrograms of free fatty acids. The abundant free fatty acids appear to account for the cytotoxic activity of the T.c homogenate, although they occurred in T.c under weakly active condition.

[Double primary malignant neoplasm of renal cell carcinoma and stomach cancer: report of two cases]

Two cases of double primary malignant neoplasm of renal cell carcinoma and gastric cancer are presented. Case 1 was a 59-year-old woman with right renal cell carcinoma (granular cell subtype) and gastric cancer (poorly differentiated adenocarcinoma). Case 2 was a 72-year-old man with left renal cell carcinoma (clear cell carcinoma) and gastric cancer (tubular adenocarcinoma). In both cases, the occult blood reactions of stool was strong and clear gastrointestinal symptoms developed. In these 2 cases of synchronous double cancer, gastrectomy following nephrectomy was performed in the same operation.

Characteristics of the anti-sheep red blood cell heterophile antibodies produced during Schistosoma japonicum infection in mice

Heterophile antibodies (Ab) against sheep red blood cells were shown to have developed in mice experimentally infected with Schistosoma japonicum (SJ). Incidence of the elevated Ab levels was markedly high in the period of 6-10 weeks following infection. By means of absorption tests, the heterophile Ab could be distinguished from classical human heterophile Ab of Paul-Bunnell, Hanganutzui-Deicher, and Forssman types. Antigen(s) cross-reactive with the heterophile Ab was found only in goat red blood cells (RBC) but absent on RBC of other species, in various tissue homogenates of syngeneic mice, or in SJ parasites and their eggs. The Ab activity seems to be mainly localized in immunoglobulin classes other than IgM.

Hemolytic factors in Schistosoma japonicum eggs

Extracts of Schistosoma japonicum eggs were found to exhibit hemolytic activity on erythrocytes of various species. The hemolytic reaction took place more rapidly at 37 degrees C than at 4 degrees C and did not require divalent cations. The degree of hemolysis was dependent on the concentration of the egg extracts. The hemolytic factors seemed to be lipid in nature because of being heat-stable and soluble in chloroform solvent. Further analysis by means of thin-layer chromatography showed that hemolytic activity in the extracts was due to free fatty acids. Analysis by gas chromatography revealed that fatty acids in the egg extracts consist of myristic, palmitic, palmitoleic, stearic, oleic, linoleic, linolenic, and arachidonic acids. Among them, based on the experiments with commercially available fatty acids, arachidonic acid was the most intensively hemolytic, followed by linoleic, linolenic, oleic, palmitoleic, and myristic acids in that order, whereas palmitic acid showed weak activity only in the presence of divalent cations. From the estimated calculation, it was assumed that 1 mg of protein of the egg extracts contains as much as 0.22 mg of free fatty acids.

The presence of anti-sheep red blood cell heterophile antibodies and their characteristics in murine schistosomiasis japonica

Sensitive methods of an enzyme-linked immunosorbent assay (ELISA) using red blood cells (RBC) have been developed and were applied to the detection of anti-sheep red blood cell (SRBC) heterophile antibodies (Ab) present in sera of Schistosoma japonicum (SJ)-infected mice. The indirect hemagglutination test (IHA) was used for the purpose as well. By these methods a significant increase in the heterophile Ab levels was demonstrated in the mice particularly after 6-10 weeks of infection. The heterophile Ab in SJ-infected mice were predominantly immunoglobulins resistant to 2-mercaptoethanol treatment and had temperature-independent reactivity. In an attempt to investigate the immunological specificity of the heterophile Ab, various absorption tests were performed; Davidsohn's differential absorption test revealed that the heterophile Ab were distinct from Forssman antibody, Paul-Bunnell antibody and heterophile agglutinins known to appear in serum sickness. The heterophile Ab were absorbed only with SRBC and goat red blood cells, not with other species of RBC such as human O Rh-, O Rh+, A Rh+, B Rh+, mouse, ox, chicken, horse, rabbit, guinea pig, and rat RBC, or syngeneic tissue homogenates including brain, lung, liver, spleen, kidney, muscle, and thymus. This heterophile antibody response is not a consequence of a specific immune response directed to the antigens of SJ parasites, since absorption of the heterophile Ab with SJ adult worms or an egg preparation did not reduce the heterophile Ab level.

[Studies on predilection area of gastric ulcer viewed from gastric motility (author's transl)]

Clinically, most gastric ulcers are located in the region of the incisura angularis, but they are least found along the greater curvature. To elucidate this difference, following experiments were carried out. A total of 22 mongrel dogs were used. A set of bipolar electrodes and/or a water-proof strain gage were chronically implanted at both the incisura and the corresponding site of the greater curvature. Electrical and contractile activities of these two sites were compared at the fasted state and under the stimulations by food, neostigmine and tetragastrin. Results are summarized as follows. 1. Electromyographically, the propagation velocity was always greater along the greater curvature than the lesser curvature. The discharge interval of BER and incidence of antiperistalsis were identical for both the lesser and greater curvature. 2. Through the course before and after the stimulation, there was no difference in the frequency of contraction waves, while the amplitude and motility index of the contraction were definitely greater at the incisura than the corresponding greater curvature. In conclusion, the present study revealed that the contractile force of the incisura was always greater than that of the corresponding greater curvature. It is possible that the peristaltic contraction could cause stronger repetitive ischemic condition of the incisura than the corresponding greater curvature. It is estimated that the gastric motility is one of the important factors for the predilection or delayed healing of gastric ulcers seen in the region of the incisura angularis.