Thermal tolerance during S phase for cell killing and chromosomal aberrations

Synchronous Chinese hamster ovary cells in early S phase were obtained by selecting mitotic cells, accumulating them at the G1/S border by incubating them in aphidicolin for 12 h, and then incubating them for 2 h after releasing them from the aphidicolin block. To determine if thermotolerance could be induced, the cells were heated at 43 degrees C for 20 min in early S phase, incubated for 160 min, and then heated a second time at 43 degrees C for different durations (30-100 min). For the control, nontolerant population, the cells in early S phase were incubated for 50 min and then heated once at 43 degrees C for different durations (20-60 min). Flow cytometric analysis indicated that the population receiving the second heat dose was in the same part of S phase as the population receiving the single heat dose. A comparison of the heat response for the two populations indicated that heating during early S phase induced thermotolerance for both cell killing and chromosomal aberrations; i.e., for 10% survival, which corresponded to 10% of the cells being cytologically normal, the thermal dose was twofold greater in the thermotolerant cells than in the control, nontolerant cells. Furthermore, this thermotolerance developed during S phase. These observations support the hypothesis that heating during S phase kills cells primarily by inducing chromosomal aberrations.

Effects of pH on heat sensitization of mammalian cells with procaine hydrochloride

The enhancement of heat killing of CHO cells by treatment with 7 mM procaine HCl increased when cells were treated under alkaline conditions. Below a pH of 6.9, very little heat sensitization was observed; however, as the pH was increased to 7.4 and above, considerable heat sensitization occurred. There were no changes in intracellular pH at the beginning of heating that could be responsible for this phenomenon.

Zygosity in two cases of triplet

A total of 11 techniques including 57 items for zygosity diagnosis was employed in two sets of triplet. Namely, placenta-fetal membrane, LDH isoenzymes, etc. The authors made an investigation in detail on the pedigree history of polyembryony and systematic analysis of two sets of male triplets. The conclusion was that the first triplet came from a single ovum, whereas the second triplet developed from double ova. Different methods for the zygosity diagnosis were discussed. It was considered that there was hereditary influence in the occurrence of triplets developing either from a single ovum or from multiple ova.

Experimental studies on the late effects of female sex hormones

Inj. Hydroxyprogesterone Co. (EP) was injected i.m. into female Wistar rats, different strains of mice of both sex and Syrian golden hamsters with doses of 5-100 times the human contraceptive dose once or twice a month for 10-32 times. In some experiments EP was combined with whole-body 3 Gy gamma ray radiation once or twice. Results show that EP has obvious carcinogenicity and can enhance the gamma ray carcinogenicity, thereby increasing the tumor incidence or the ratio of malignant to benign tumours. Carcinogenic mechanisms of EP have also been studied.

CD4-independent, productive infection of a neuronal cell line by human immunodeficiency virus type 1

One neuronal cell line (SK-N-MC) was found to be susceptible to productive infection by multiple isolates of the human immunodeficiency virus type 1 (HIV-1). Characterization of SK-N-MC cells showed that these cells are neuroectodermal in origin in that they express dopamine hydroxylase, catecholamines, neuron-specific enolase, and neurofilaments. Despite their susceptibility to HIV-1 infection, SK-N-MC cells had no detectable CD4 and this infection was not blocked by anti-CD4 monoclonal antibodies (OKT4A, Leu3A) or recombinant soluble CD4. These experiments demonstrated that certain cells of neuroectodermal origin are susceptible to infection in vitro by HIV-1 via a CD4-independent mechanism.

[Isolation and fermentation conditions of polyvinyl alcohol-degrading enzyme producing strain]

A bacterium D8 strain which high efficiently degrading PVA was isolated from waste water of factory. The strain possesses the abilities of completely degrading 0.5 per cent of PVA (500, 1700) included in the culture medium for four days. It was identified Pseudomonas pseudoalcaligenes. Fermentation conditions of the strain have been investigated. The suitable medium consisted of PVA 1.5% (NH4)2SO40.1%, K2HPO4 0.24%, KH2PO4 0.04%, MgSO4.7H2O 0.035%, NaCl 0.01%, FeSO4 0.001%, yeast extract 0.15%, pH 7.5. The optimal condition for enzyme production are as follows: 250 ml shake filled with 30 ml medium, 30 degrees C, 160n/min incubation period 72 h. Under such conditions enzyme activity is highest.

Generation and characterization of monoclonal antibodies to the putative CD4-binding domain of human immunodeficiency virus type 1 gp120

A panel of seven monoclonal antibodies against the relatively conserved CD4-binding domain on human immunodeficiency virus type 1 (HIV-1) gp120 was generated by immunizing mice with purified gp120. These monoclonal antibodies reacted specifically with gp120 in an enzyme-linked immunosorbent assay and Western blots (immunoblots). By using synthetic peptides as antigens in the immunosorbent assay, the epitopes of these seven monoclonal antibodies were mapped to amino acid residues 423 to 437 of gp120. Further studies with radioimmunoprecipitation assays showed that they cross-reacted with both gp120 and gp160 of diverse HIV-1 isolates (HTLV-IIIB, HTLV-IIIRF, HTLV-IIIAL, and HTLV-IIIWMJ). They also bound specifically to H9 cells infected with HTLV-IIIB, HTLV-IIIRF, HTLV-IIIAL, HTLV-IIIZ84, and HTLV-IIIZ34 in indirect immunofluorescence studies. In addition, they blocked effectively the binding of HIV-1 to CD4+ C8166 cells. Despite the similarity of these properties, the monoclonal antibodies differed in neutralizing activity against HTLV-IIIB, HTLV-IIIRF, and HTLV-IIIAL, as demonstrated in both syncytium-forming assays and infectivity assays. Our findings suggest that these group-specific monoclonal antibodies to the putative CD4-binding domain on gp120 are potential candidates for development of therapeutic agents against acquired immunodeficiency disease syndrome.

[Functional dominance in the lacrimal canaliculi]

Past reports ignored the functional relationship between the upper and lower lacrimal canaliculi. The authors measured the lacrimal function in 50 normal eyes of 27 subjects and found that the drainage was more rapid in the lower lacrimal canaliculi of 25 eyes and in the upper canaliculi of 22 eyes, while the drainage time was equal in 3 eyes. The drainage in 25 eyes with both the upper and lower canaliculi open was more rapid than with any one canaliculus occluded. The authors suggested that the function of the lacrimal canaliculi might be classified into three types: the dominating, the dominated and the balanced. There was no statistical difference (P greater than 0.05) between the numbers of dominating upper or lower canaliculi in this series. The function of the upper and lower canaliculi operated synergically and complete drainage was not accomplished by any one canaliculus alone.

HIV-1, HIV-2, and HTLV-I infection in high-risk groups in Brazil

We conducted a serologic survey for antibodies to human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2) and human T-cell lymphotropic virus Type I (HTLV-I) in 704 Brazilians with the acquired immunodeficiency syndrome (AIDS) or at risk for it. The study population included 70 homosexual men (11 of whom were prostitutes), 58 bisexual men (19 of whom were prostitutes), 101 female prostitutes from three socioeconomic groups, 13 wives of men with hemophilia who were seropositive for HIV-1 antibodies, and 47 blood donors with positive Venereal Disease Research Laboratory tests for syphilis, all from Rio de Janeiro; 86 female prostitutes from two rural towns in Minas Gerais; 133 patients with AIDS from São Paulo; and 196 men with bleeding disorders who were seropositive for HIV-1 antibodies on enzyme-linked immunosorbent assay, from São Paulo and Rio de Janeiro. The prevalence of HIV-1 infection was highest in the homosexual male prostitutes (45 percent), the wives of patients with hemophilia (38 percent), the bisexual men (28 percent), the homosexual men who were not prostitutes (19 percent), and the female prostitutes from the lower class (9 percent). Combined HIV-1 and HIV-2 infection was found in 3 percent of the patients with AIDS and in 1 percent of the homosexual men. The prevalence of HTLV-I infection ranged from 1 percent in rural female prostitutes to 13 percent in HIV-1-positive men with bleeding disorders in Rio de Janeiro. Combined HIV-1 and HTLV-I infection occurred in 1 to 11 percent of some male subgroups. We conclude that in Brazil HIV-1 infection is already well established among homosexuals, bisexuals, and lower-class female prostitutes, with bisexual men probably acting as a bridge between the heterosexual and homosexual communities, that HTLV-I infection is prevalent in groups at risk for AIDS, and that HIV-2 infection has already been introduced into the country.

Safety evaluation studies of SGF gum--a potential food additive from the seed of Sesbania cannabina

SGF gum, derived from the plant Sesbania cannabina, has properties very similar to those of guar gum. Because it is much cheaper than guar, SGF gum is of interest as a possible new food additive. It has therefore been tested in rats for acute, short-term and subchronic toxicity, teratogenicity and effects on reproductive performance, and a 1% concentration in the diet has been identified as the no-effect level. The tests complied with the guidelines issued by the Chinese authorities. Mutagenicity studies, Ames tests and a micronucleus test gave negative results, and a dominant lethal test in mice was negative at the 1% dietary level, although at 5 and 10% the results were equivocal. No adverse changes were elicited in 23 human volunteers who consumed a total of 960 mg SGF gum during a 30-day period during which they consumed, daily, 80 g ice-cream containing 0.04% SGF gum instead of the usual thickener. On the basis of applying a 100-fold safety factor to the findings in the animal studies, an acceptable human daily intake of 6 mg/kg is suggested.

Establishment and biological properties of mouse granulocytic leukemic cell line-L833

A granulocytic leukemic cell line, called L833 has been established through culturing in vitro from mouse bone marrow of transplantable granulocytic leukemia. More than 280 passages have been performed in 3 years. Cell growth has been rapid and stable. Incidence of tumour formation was 100% with various routes of inoculation. The nature of granulocytic leukemia was confirmed by examination of cytology, cytochemistry, pathology and ultrastructural changes. Analysis proved chromosomes to be hypodiploid with model number of 39, loss of chromosomes, and presence of a marker. Besides the chromosomal change as mentioned above, both L883-A and L833-B derived from colonies formed from the L833 cells cultured in semi-solid agar medium, have their own marker. The cell line was sensitive to various types of antitumour agents in varying degrees. It was also sensitive to ionizing radiation. D0 values of L833 and L883-A cells were 98.8 and 104.9 rad, respectively. The results were similar to that of L801. Establishment of this cell line is of important significance for studying leukemia and screening anti-tumour agents, as well as provides a useful direct, economic and precisely quantitative tool for other relative studies.

[Chemoprevention of cancer of the uterine cervix--preliminary study on the intervention of the cervical precancerous lesion by retinamide RII]

Twenty seven women with mild, moderate or severe cervical dysplasia proven by pathology were treated by retinamide RII suppository. Retinamide RII suppository, 10 mg QD, was given intravaginally for six months (three months as a course). Clinical examination, Papanicolaou cytology and tissue biopsy under colposcope were carried out before and after treatment. The results indicated that after the second course, 26 out of 27 patients responded; of them, precancerous lesions disappeared in 24 and even normal squamous epithelium was observed in 3. The overall response rate was 96.29% and the marked response rate was 88.89%. The general side effects were mild. There was little cervical and vaginal irritation which was well tolerated. The results of this clinical trial make available a practical base for chemoprevention of cervical cancer.

[Brenner tumor of the ovary--a clinicopathological report of 5 cases]

This paper reports 5 cases of Brenner tumor of the ovary treated in our hospital from 1967 to 1985. The patients' mean age was 54.6 years. Three lesions were solid, 1 cystic and the other occurred on the wall of a borderline malignant mucinous cystadenoma. All the 5 cases were benign by pathology. The clinical symptoms were abdominal pain in 3 cases, 2 of which had a torsion of the tumor pedicle, abdominal mass in 1 and abdominal swelling in the other. All the cases possessed the same feature that the tumor was composed of both hyperplastic epithelial nest and fibrous stroma. In histology, there were 3 transitional epithelial cell types and 2 basal cell-like types. Histogenesis of the Brenner tumor, according to the authors' observation, was shown by: 1. The epithelial cell nests of Brenner tumor were similar to the transitional epithelium of the urinary tract in 60% of these cases; basal-like cell in the early stage of differentiation comprised 40%, 2. In 80% of patients, there was observed, in the cell nuclei, a longitudinal groove, which resembled the cells of Walthard cell nests; 3. The transitional epithelial cells were found in the cyst wall of 1 polycystic tumor; another case was complicated with mucinous cystadenoma and there was no sharp demarcation between the two tumors under microscope. It suggests that the histogenesis imply that the Brenner tumor may arise from the coelomic epithelium of para-mesonephros. The authors also believe that certain Brenner tumors have endocrine activity, but the relation between which and the tumor stroma luteinization should be further studied.

[In vitro studies of the cell cycle of mouse myelomonocytic leukemia using a fluorescence activated cell sorter and autoradiography]

Cell cycle and various phase time of mouse myelomonocytic leukemia cells were studied in vitro with Fluorescence Activated Cell Sorter (FACS 420, Becton-Dikinson FACS Systems, Sunnyvale, CA, USA) in testing cellular DNA content and with autoradiography. At the same time, doubling time was calculated by counting the number of cells cultured in vitro within 6 days following implantation. According to the cellular DNA content, the proportions of various cell phases in the whole cell population were as follows: G1, S and G2 plus M phases take up 30.5%, 47.9% and 21.6%. Basing on autoradiography and direct counting, the cell number, the cell cycle, duration of various cell phases and doubling time were as follows: LI = 98.0%, MI = 1.7 +/- 0.9%, TG1 = 4.9 hrs, TS = 8.0 hrs, TG2 = 2.8 hrs, Tm = 0.3 hr, TC = 16.0 hrs, TD = 17.0 hrs. FACS assay showed that the duration of various cell phases are quite similar to that calculated by autoradiography. Therefore a simple and rapid FACS method may be widely used in the studies of cell cycle instead of autoradiography if estimating computer program is available.