Studies on antipeptic ulcer agents: the quantitative structure-activity relationship analysis of heterocyclic aldehyde N4-substituted phenyl (thio) semicarbazones

Forty-five condensation products of furan-, pyrrole- and N-methyl pyrrole-alpha-carboaldehyde with N4-3- or N4-4-substituted phenyl semicarbazones and thiosemicarbazones were designed to optimize the antiulcer activity of a previously derived lead structure, formula II. Quantitative structure-activity relationships revealed that among the series of semicarbazones, increasing hydrophobicity and the introduction of electron-donating groups into the phenyl ring raise the antiulcer activity. Generally, semicarbazones are more active than the corresponding thiosemicarbazones. The wide gulf between the activity and toxicity of two derivatives (Compounds III and IV) necessitates further investigation of their pharmacological effects.

Inhibition of anaphylaxis-evoked intestinal fluid secretion by the dual application of an H1 antagonist and cyclooxygenase inhibitor

The regulation of anaphylaxis-mediated fluid secretion by the small intestine was examined in rats immunized by infection with Trichinella spiralis and reinfected by intraduodenal injection with L1 larvae. Net fluid secretion, which was measured as the volume of fluid present in the intestine 30 minutes after the challenge infection, was significantly greater in both actively and passively immunized rats than in nonimmune rats. The amount of fluid recovered from the immune host was equivalent to that secreted in response to 50 micrograms/kg of prostaglandin E2 or 250 micrograms/kg of cholera toxin. Worm-induced fluid secretion in immune hosts was reduced by treatment with diphenhydramine and inhibited by the dual application of diphenhydramine and indomethacin. Indomethacin alone had no effect despite inhibiting mucosal prostaglandin synthesis. Fluid secretion was unaltered by prior treatment of immune rats with a 5-lipoxygenase inhibitor, L-651,392, and only slightly reduced when L-651,392 was used in combination with indomethacin. After a challenge infection, more histamine was released into intestinal loops of immune rats than those of nonimmune rats. Prechallenge treatment of immune rats with indomethacin caused a twofold increase in histamine release. In summary, anaphylaxis-induced fluid secretion in the small intestine is mediated largely by histamine and cyclooxygenase products. This secretion can be lowered by treatment with diphenhydramine and further reduced by diphenhydramine in combination with indomethacin. The paradoxical effects of indomethacin when used alone and in combination with diphenhydramine are explained by the downregulation of histamine release by products of the cyclooxygenase pathway.

[New approach for management of retinal detachment with macular hole]

Three kinds of unconventional methods were used to treat retinal detachment with macular hole in 17 cases (17 eyes). A combination of vitrectomy, transscleral drainage and intraocular air injection was used for the cases of retinal detachment with macular hole and evident vitreous traction. Transscleral drainage combined with air injection was used for those of macular hole without vitreous traction. For the cases of combined peripheral and macular holes, we treated only peripheral holes, ignoring the macular hole. After a 3-16 months follow-up, 15 out of the 17 eyes obtained retinal anatomic reattachment (88.2%), 10 eyes had their vision improved, 4 eyes remained unchanged, 9 eyes obtained a visual acuity of better than 0.05 postoperatively. Compared with the conventional method of macular buckling, these procedures have the advantages of less damage to macula, less complications and more satisfactory visual improvement.

[Species differences in subacute toxicity of pyrrole aldehyde N4-(4-methoxyphenyl) semicarbazone]

The subacute toxicity of compound 1 was investigated in rats and dogs. Compound 1 was administered orally to rats of both sexes at daily doses of 0.5, 1.0 or 2.5 g/kg for 3 months. No change attributable to the administration of compound 1 was found either in blood count or in histopathological examination. Decreases in SGPT, alkaline phosphatase and lactic acid dehydrogenase and an increase in serum cholesterol were detected. Compound 1 was mixed with food and given to dogs of both sexes daily at doses of 0.2 or 0.5 g/kg for 3 months. Severe toxic symptoms including anorexia, emesis, ataxia and convulsive seizures were observed. A decrease in SGPT and increase in alkaline phosphatase were also detected. Hyperemia of the duodenal mucosa and severe kidney lesions were found in histopathological examination. Neither abnormality of appearance nor histopathological change was found in a pig receiving compound 1 at the daily dose of 0.1 g/kg for 3 months. The results suggest that there are differences of compound 1 metabolism among the species used in this study.

[Safety observation of attenuated live hepatitis B vaccine (H2 strain) in humans]

3089 healthy persons, aged 4 to 27 years, have been inoculated in 3 batches with attenuated live hepatitis A vaccine (H2 strain) since May, 1987. Each subject received 10(8.5) TCID dosage subcutaneously in the upper arm. None of the recipients developed any local or systemic reaction during a 42-day followup after vaccination. The serum enzyme activities, including SGPT/ALT and LDH5, were within normal range during the 4th to 16th weeks of serial tests after inoculation. The study of hepatitis A virus (HAV) shedding in feces of 4 subjects showed that no hepatitis A antigen (HAAg) was detected with antigen capture ELISA, but infectious HAV was recovered from stool-cell cultures in three of four recipients. No patient with hepatitis A was found within 6 months after vaccination in the institution where the HAV vaccine was used. In addition, no immunological evidence was seen that the HAV vaccine recipients can transmit HAV after the investigation of serological epidemiology at a class in which the HAV vaccine was tested. It is suggested that the potential of hepatitis A related to HAV vaccine among the non-vaccinated persons is rare. Seroconversion occurred at a mean time of 2 to 5 weeks after inoculation, and the positive rate of specific antibody was 95.6%.

Role of molecular diffusion in conventional and high frequency ventilation

The influence of molecular diffusion on gas-mixing during conventional mechanical ventilation (CMV) and high frequency ventilation (HFV) was studied by observing the wash-in of six poorly soluble, inert gases in arterial blood. Anesthetized dogs were ventilated either with CMV or HFV. Following a step change in inspired gas composition, the increase in arterial concentrations of hydrogen, helium, methane, ethane, isobutane, and sulfur hexafluoride was determined by gas chromatography. The relative gas diffusivities encompassed a range of almost one order of magnitude. Propane, present in inspired gas during both the control and wash-in phases, served as an internal reference for calculation of blood tracer concentrations. The wash-in of all six inert gases followed a single exponential time course during both CMV and HFV. The rate of wash-in of each gas decreased with increasing molecular weight (MW). The relationship of rate constants to a measure of relative diffusivity (MW-0.5) was significantly different than zero for both types of ventilation. The slope of this relationship was three times larger for CMV than HFV, indicating that molecular diffusion has a greater role in gas mixing during ventilation with large tidal volumes. Diffusion has a minor role in gas mixing during high frequency ventilation with small tidal volumes. Demonstration of the presence of gas separation secondary to molecular diffusion during HFV is enhanced by measuring wash-in, rather than wash-out, of inert gases because gas separation is likely to be obscured as exhaled gases pass through the well-mixed central airways during gas wash-out.

Control of src kinase activity by activators, inhibitors, and substrate chaperones

The activities of src tyrosine kinases are greatly influenced by substrate modulators (chaperones). In the presence of bovine serum albumin, the phosphorylation of a random polymer of glutamic acid, alanine, and tyrosine (1:1:1) by src kinases is stimulated 20- to 100-fold, but there is little stimulation with a polymer of glutamic acid and tyrosine (4:1) as substrate. This suggests that serum albumin interacts with the substrates rather than with the enzyme. groEL and several other heat shock proteins also stimulate the phosphorylation of a random polymer of glutamic acid, alanine, and tyrosine (1:1:1). In the absence of substrate modulators, the phosphorylation of calmodulin and of several ras proteins by src kinase is barely detectable. In the presence of polylysine or protamine, marked phosphorylation is observed. Another type of control of src kinase activities appears to be directed toward the enzyme rather than the substrate. Triton X-100 extracts of plasma membranes of bovine brain contain a heat-stable factor that stimulates c-src kinase activity with any of the polymers as substrate. The same extract contains a heat-labile factor that preferentially inhibits c-src kinase activity. The two factors are separated by DEAE-Sephacel and phosphocellulose chromatography. The presence of the activator enhances the potency of the inhibitor.

[Comparative study of Campylobacter pyloridis and Campylobacter jejuni under electron microscope]

Specimens were made by preparing the ultrathin sections after negative staining and ruthenium red staining. The specimens were observed under electron microscope. Results revealed that the shapes of Campylobacter pyloridis (Cp) and C. jejuni (Cj) were similar, but distinctive differences in their structures were observed. Cp had one to five sheathed flagella at one end with bulbous tips. Cj had only one unsheathed flagellum on each end without a bulbous tip. The cell body of Cp was longer than that of Cj. A layer of thick and dense delicate filament-like substance was attached to the surface of the cell body of Cp in the ultrathin sections with ruthenium red staining, in the case of Cj only a little of such a substance could be noted.

[Prenatal sex identification with biotinylated human Y-specific DNA probe]

Using biotinylated human Y-specific DNA probe PHY2.1 and Cos 84, we carried out Southern and dot hybridization with human DNA from artificially aborted chorionic villi, and with DNA of peripheral lymphocytes from normal male and female. The results show that PHY2.1 may be applied in prenatal sex identification both by Southern and by dot hybridization but with Cos 84, only Southern hybridization could be used.

The changes of BPA level in 31 cases of children with aplastic anaemia and its clinical significance

Burst-promoting activity (BPA) was measured in the sera from 31 children with aplastic anaemia (AA). BPA levels were elevated in most of the children with AA (65.2%), the mean value (137.7 +/- 18.4%) being significantly higher than that in normal children (69.6 +/- 9.4%), in children in the recovery period and in children with non-aplastic anaemia. There was a negative relationship between the BPA level in children with AA and the peripheral haemoglobin concentration. The BPA level was higher in those whose duration of illness was shorter than 1 year. In three cases of AA caused by chloramphenicol and benzene hexachloride and one case of congenital pure red cell AA, the BPA level was not elevated. Eleven patients received fetal liver cell suspensions intravenously (FLI). After FLI the BPA level in their sera was significantly reduced. According to these results, it appears that the elevation of BPA level is a special phenomenon of AA. The measurement of BPA in serum is helpful for differentiation between AA and other kinds of anaemia. The elevation of the BPA level in serum is a biological compensation for the haematopoietic disorder, and the measurement of BPA in the serum of patients with AA may be helpful in evaluating the haematopoietic condition.

[Purification and characterization of beta-N-acetyl hexosaminidase from Aspergillus tamarii]

A beta-N-acetylhexosaminidase from mycelium-free culture filtrate of Asp tamarii S215 was purified to PAGE homogenous by ammonium sulfate and polyethylene glycol fractionation precipitation followed by Sephadex G-50 desalt, DEAE-Sephadex A-25 chromatography, hydroxyapatite chromatography and DEAE-Sephadex A-25 rechromatography with 170-fold purification and 24.7% recovery. The ratio of the beta-GlcNAcase and beta-GalNAcase was 2.5 and remained constant throughout the purification. The Mr estimated with concentration gradient PAGE was 140,000 and subunit Mr determined with SDS-PAGE was 72,000, the number of subunit were 2. The pI was 4.2 determined by PAGIEF. The optimum pH was 5.5-6.5 and 5.0-6.0 for beta-GlcNAcase and beta-GalNAcase respectively with stable pH range 5.5-8.3 for both. The optimum temperature was 60 degrees C for beta-GlcNAcase and beta-GalNAcase. The residual activity of beta-GlcNAcase was 52.7% after treated at 50 degrees C for 8 h and it was 44.9% for beta-GalNAcase. The residual activities of both were down to 1% after treated at 62 degrees C for 10 min. The activity was slightly activated by Mn2+ or Fe2+, while strongly inhibited by Hg2+ and slightly by Ag+, Cu2+, Pb2+, Cd2+ or Zn2+. Analyses of amino acids composition showed that the beta-HexNAcase contained about 24.2% acidic amino acids and 14.9% basic amino acids and only 0.6% methionine.

[Study on change in zinc concentration for diabetic cataractous lenses in rats by means of XIXA]

The SD rats were injected with streptozotocin to induce diabetic cataract. Element Zn as well as K, Ca, Mn, Fe, Cu, Pb, Se, etc. in the eye lenses was determined by means of X-ray induced X-fluorescence analysis (XIXA). Compared to values for normal healthy rats, the concentration of Zn and Fe in the cataractous lenses increased, the concentration of K decreased, and that of the others did not change prominently. The change in Zn concentration was probably to meet the needs of the metabolic adjustment in the eye lenses, which would not be the reason for directly inducing diabetic cataract.

Micro-vitreous surgery combined with scleral encircling for the management of complex retinal detachment

50 cases (50 eyes) of various complex retinal detachments (RD) were treated with a combination of vitrectomy, membrane peeling, intraocular air tamponade and scleral encircling. RD with opaque media, RD with proliferative vitroretinopathy, traction RD due to trauma or other factors, RD with posterior breaks, and giant tears were included. During the follow-up periods of 3-12 months, 27 cases (54%) obtained anatomic reattachment, 23 failed (46%). Of the successful case, 24 eyes achieved improvement, 2 eyes remained unchanged, and one eye became worse in their vision. The surgery complications were: retinal haemorrhage, choroidal haemorrhage, iatrogenic tears, and the development of cataract.

[Electron spin resonance (ESR) study on hair of rats with diabetic cataract]

The hair taken from 40 rats with diabetic cataract and 20 normal controls was tested by using ESR. It was found that the 'g factor' of the hair of the rats with diabetic cataract is higher than that in normal controls. The intensity of ESR signals of the hair taken from rats with diabetic cataract is three times higher than that of ESR signals of the hair from the normal controls. The results have suggested a good reappearance and a remarkable increase in number of the free radicals and other particles of paramagnetic substances during the course of the development of the rats' diabetic cataract. The study provides new scientific data for the theory of free radicals damaging to the crystal in the process of the formation of diabetic cataract.

[Detection of sorbitol content in crystalline lens of normal rats and rats with diabetic cataract by 1H-NMR]

The pulse Fourier NMR was employed to measure the artificial diabetic cataract lens at various stages of its formation, and the lenses of the normal rats. Data obtained by using this method show that all the peaks that of water concentrate in the range of delta less than 4 ppm. The peak value at delta = 3.20 ppm is on a marked increase during the formation of cataract which is caused by the phosphate metabolites, such as GPC, ATP, ... etc, in cataract lens. With the development of the disease, the peak width at delta = 3.73 ppm becomes greater and greater, which shows that the activity of sorbitol dehydrogenase has decreased. This leads to a high concentration of the sorbitol in the cataract lens. Consequently, the osmosis pressure in the cataract lens is increased, and excessive water might dip into the crystalline lens to keep the balance of the osmosis pressure. And this might result in the hydration of the fiber cell of the crystalline lens, which might cause a swelling or blisters. These results are in favour of the prolongation of the relaxation time of cataractous lens reported in our other papers, and also support those gained by biochemical studies issued in the medical literature.

A New Minor Saponin from the Leaves of Panax ginseng

Seventeen compounds were isolated from the leaves of PANAX GINSENG C. A. Meyer. Among them, a new minor saponin was established as 3beta,6alpha,12beta-trihydroxy-dammar-20(22), 24-diene-6- O-alpha- L-rhamno-pyranosyl-(1-->2)-beta- D-glucopyranoside ( 2). Fourteen compounds were identified as 20( R)-protopanaxadiol ( 1), 20( R)-protopanaxatriol, ginsenoside-Rh (3), 20( R)-ginsenoside-Rh (2), 20( S)-ginsenoside-Rh (2), ginsenoside-Rh (1), -Rg (3), -Rg (2), -Rg (1), -Re, -Rd, -Rc, -Rb (2), -Rb (1); the others are still under investigation.

[Study on the variation of relaxation time in diabetic cataractous lenses of rats by using NMRA]

Nuclear magnetic resonance analysis (NMRA) was used to measure the relaxation time T1 and T2 of the protons in the different-stage-diseased lenses of rats with diabetic cataract caused by the streptozotocin, and the results were put in comparison with those obtained from the control group, showing that after one month of medication the values of T1 and T2 in the cataractous lenses are greater than those gained from the control group. The variation, as time goes on, becomes greater and greater. T1 and T2 indicate the speed of the free induction decay (FID) signals, and the variation of the FID signals are in direct proportion to that of the proton content of the samples. This shows that an increase in T1 and T2 indicates an increase in the water content in the diseased lenses, and the changes in ratio of "bound" water to free water. Such changes may be explained that the space for "bound" water is occupied by some other macromolecules, causing the alteration of the macromolecular structure, and consequently the aggregation of protein and the degeneration or dehydration or dehydration of the membrane occur, which may give rise to another scattering centre. So the scattering of the lens increases and its transparency decreases. This result is in agreement with some reports in the medical literature. As T1 and T2 are quite different in the normal and pathological tissues, and the protons are the most extensive nucleus in all biological tissues, NMR is a very important method to determine the proton relaxation time in the biological tissue and to judge if it is normal or not.(ABSTRACT TRUNCATED AT 250 WORDS)

Birefringent tuning double frequency He-Ne laser

Experimental details are given of a novel, promising kind of double frequency laser-with power output of 0.8-1.4 mW, large frequency difference from 37 MHz to a longitudinal mode interval, and frequency stability of 10(-5), and its potential uses are discussed.

[Volatile components of herbal Cynomorii]

The volatile components were obtained from Herba Cynomorii for the first time (yield 0.02%). These components were analysed by TLC and GC-MS. Twenty-two compounds, including the main components hexadecanoic acid and 9-octadecenoic acid, were identified. Their percent contents were given.

[Separation of 20(S)-ginsenoside-Rg2 and its 20(R) epimer by reversed phase low pressure column (Rp-18) chromatography]

20(S)-Ginsenoside-Rg2 and its 20(R) epimer were successfully separated using reversed-phase low pressure column (Rp-18) chromatography. The method has proved very convenient and rapid.

Involvement of type I hypersensitivity in rapid rejection of Trichinella spiralis from adult rats

The role of type I hypersensitivity in the rapid rejection of Trichinella spiralis from actively and passively immunized rats was examined. Net intestinal fluid secretion, which occurs during the rejection of the parasites, was used to verify the expression of local anaphylaxis and was examined for its possible role in the rejection process. Worm establishment in the small intestine 30 min after intraduodenal inoculation was significantly reduced in rats that were passively immunized with immune serum containing anti-Trichinella IgE as compared with recipients of normal serum. Worm-induced fluid secretion in immune rats was completely inhibited by the combined action of indomethacin and diphenhydramine. However, worm rejection was not affected. L-651,392, a 5-lipoxygenase inhibitor, also failed to prevent rejection. Ketanserin (a serotonin S2 receptor antagonist) and MDL-72222 (a serotonin S3 receptor antagonist) together blunted the rapid rejection response and reduced fluid secretion. Furthermore, intra-arterial perfusion of serotonin into nonimmune rats caused fluid secretion and reduced worm establishment. In nonimmune rats prostaglandin E2, cholera toxin, and hypertonic Krebs-mannitol solution were used to evoke the same level of intestinal fluid secretion as that induced by reinfection in immune rats or by serotonin in nonimmune hosts. When larvae were inoculated into the secreting gut, their infectivity was unaffected. The results suggest that anaphylaxis is involved in the rapid rejection of T. spiralis in immune rats and that serotonin is a possible chemical mediator of worm rejection. Although the mode of action of serotonin in the rejection process remains unknown, its possible involvement through fluid secretion can be ruled out.

[Studies on the susceptibility among geographic strains of Aedes albopictus in China to infection with dengue viruses]

The comparative susceptibility to dengue serotype 1, 2 and 4 viruses infection of 9 geographic strains of Azdes albopictus was studied by means of experimental feeding the mosquitoes on pledgets soaked with virus-erythrocyte suspension and intrathoracic inoculation with dengue viruses. Variation in susceptibility for both dengue serotypes 1 and 2 was found among the geographic strains by feeding, but no significant difference among those by intrathoracic inoculation. It was evident that a "gut barrier" was involved. Thresholds of oral infection were not the same for dengue serotypes 1, 2 and 4. In terms of infection rate, Haikou strain was more susceptible to all three serotypes of viruses; Beijing and Chengdu strains were more susceptible to serotypes 1 and 2, respectively. All the geographic strains were more susceptible to dengue serotype 2 comparing with other two serotypes. The mosquito head squash method for demonstrating dengue virus antigen by indirect fluorescent antibody technique was modified by mosquito brain tissue smear. This would be more accurate in detecting the dengue virus antigen in the brain tissue.

Jaundiced Gunn rats have increased synaptic delays in the ventral cochlear nucleus

Recordings were made in vitro from cochlear nuclei of Gunn rats, a strain with a recessive mutation that predisposes rats to hyperbilirubinemia at birth. Delays between shocks to the auditory nerve and earliest synaptic responses of the cochlear nuclear neurons were on average longer in Gunn rats than in heterozygotes. Injections of sulfonamide further increased average synaptic delays in jaundiced rats. Responses to injected current in rats were like those in mice.

[Electrophysiologic effects of intravenous propafenone]

The electrophysiological effects of intravenous propafenone were studied with programmed electrical stimulation in 31 patients. Among them 29 cases with SVT (including WPW syndrome in 11, paroxysmal AF or Af in 3) and the other two cases were studied for other reasons. The results showed that: (1) Propafenone has significant effects on each part of the special conduction tissues of the heart as well as the accessory pathway. (2) It is an effective drug for treating AVNRT and the tachycardias associated with WPW syndrome. (3) There were no effects on sinus node function in all except one patient whose SNRT was prolonged to 2020 ms. (4) Neither blood pressure dropping nor other side effects were found during the studies.

[Radiotherapy of testicular infiltration in childhood leukemia]

330 boys with acute leukemia treated from 1978 to 1987 are reported. Of these patients, 24 (7.3%) developed testicular leukemia and 23 were treated by local irradiation with doses of 20-50 Gy on both sides of the testis. Swollen testis returned to normal size at the end of therapy in 10 patients whereas 13 still had enlarged testis. 18 patients were followed for 3-75 months with a mean survival time of 16.8 months. The incidence, treatment, dose of radiation, and results of therapy of testicular leukemia in children are discussed and biopsy of testis is suggested.

Brain protein kinase C phosphorylating poly(arginine,serine) or lamin B is stimulated by anions and by an activator purified from bovine serum albumin preparations

The phosphorylation of histone by purified protein kinase C (PK-C) from rat brain is dependent on the presence of Ca2+ and lipids. Phosphorylation of a synthetic random polymer of arginine and serine (3:1) is only moderately enhanced by Ca2+ and lipids, but it is greatly enhanced in the absence of Ca2+ and lipids by a contaminant in crystalline bovine serum albumin or by heated cellular fractions. The phosphorylation ratio of histone to poly(arginine,serine) varies between different PK-C fractions from brains of rat, pig, or lamb. These variations are partly caused by a PK-C isozyme that prefers poly(arginine,serine) over histone as substrate. The kinase activator (KA) was partly purified from bovine serum albumin and from extracts of plasma membranes of human placenta. KA is also present in mitochondria, nuclei, and the cytosol. Sulfates and phosphates at 10 mM substitute for KA with poly(arginine,serine) as substrate. The phosphorylation of histone III in the presence of Ca2+ and lipids is moderately stimulated by KA, but the phosphorylation of lamin B and some other endogenous proteins is greatly enhanced by KA. With histones as substrates, inorganic anions do not stimulate phosphorylation. The phosphorylation of poly-(arginine,serine) is very sensitive to low concentrations of staurosporin and is inhibited by PK-C antibody, but, in contrast to histone phosphorylation, it is resistant to sphingosine and polymyxin B. The poly(arginine,serine) phosphorylating activity is more stable at 4 degrees C than the histone phosphorylating activity, but the latter is stabilized by 0.05% Triton X-100.

Immunomodulatory mechanisms of arginine

Dietary supplementation with the amino acid arginine augments T-lymphocyte activation in response to mitogens in clinical and experimental studies. In experimental models arginine enhances specific T cell antitumor immunity. The mechanism of these immunostimulatory effects of arginine on T cell function is unclear, and the scope and specificity of arginine's influence on other components of the effector immune response such as natural killer (NK) cells and macrophages are unknown. To evaluate the role of arginine in these responses, CBA/J mice (n = 100) were randomized to receive either 1% arginine supplementation or isonitrogenous (1.7%) glycine supplementation for at least 10 days. There was no significant differences in mean body weight between groups during feeding. Arginine supplementation significantly (p less than 0.05) enhanced cytotoxic T-lymphocyte development, poly IC-inducible NK activity, and the kinetics of interleukin-2 receptor expression on activated T cells. Basal- and endotoxin-induced macrophage interleukin-1 and superoxide production were not significantly influenced by supplemental arginine although macrophage cytotoxicity in response to gamma-interferon was augmented (p = 0.07). In subsequent in vitro studies we established that certain effects (NK, cytotoxic T-lymphocyte, and T cell activation) were reproducible after preincubation for 72 hours in pharmacologic levels of arginine. The data strongly suggest that arginine mediates a direct effect on components of the immune system, which results in enhanced production or use of lymphokines.

Sister chromatid exchange and cell cycle patterns of normal human bone marrow cells after in vitro exposure to cytostatic drugs

The effect of different cytostatic chemotherapeutic drugs on the frequency of sister chromatid exchanges and growth kinetics of the bone marrow cells in normal adults was studied by means of an in vitro bromodeoxyuridine chromosome labeling method. Cytosine arabinoside, harringtonine, methotrexate, vincristine, and 6-mercaptopurine were tested. Three of these agents induced significantly high frequency of sister chromatid exchange (p less than 0.01 or p less than 0.05). The sister chromatid exchange frequency induced by cytosine arabinoside and that induced by 6-mercaptopurine were higher than those of the control group. The increased frequency of sister chromatid exchange predominated in C and A group chromosomes. At the concentration adopted by the authors, the growth kinetics were little influenced by these drugs.