[Entrainment phenomenon of atrioventricular nodal reentrant and atrioventricular reentrant tachycardias]

Atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT) were induced by esophageal pacing and their entrainment zones were examined in 20 patients. The results showed that the entrainment phenomenon, which was a common electrophysiological phenomenon in reentrant tachycardia, occurred during overdrive pacing in 19 cases (19/20). The entrainment zone was 10-70 (30.50 +/- 20.85, mean +/- s) ms. The tachycardias could not be interrupted by pacing within the entrainment zone, but they were terminated by burst pacing, with starting pacing cycle length shorter than the shortest entrainment cycle length.

[A new method of expanding free skin grafts]

The harvested skin was processed by a skin-cutting-machine into strips of 0.3 or 0.5 cm in width. Then, the skin strips were glued on alternate folds of a pleated sheet of paper, each fold of which was 0.3 cm or 0.5 cm in width. The paper with skin strips on it was spread flat and cut across into 0.3 cm or 0.5 cm strips. These strips were again glued to another sheet of plicate paper. After being cut across again, many small blocks of skin in equidistance were finally obtained. They were then grafted on the recipient site. The area of grafted wound was four fold or more of the original area of the harvested skin. This method has been used in 6 patients with good result.

Prevalence of growth hormone deficiency of children in Beijing

103,753 (male 51,994, female 51,759) primary and middle school students aged 6-15 years in two districts in Beijing city were surveyed from October 1987 to April 1989. The heights of the students were measured. According to the height standard of northern cities in China, 202 students with heights below the 3rd percentile for age were requested for detailed history, physical examination, screening GH test bone age, T4, SGPT, chest X-ray, routine urine test and sex chromatin (in female). If GH less than 10 micrograms/L, two provocative tests (L-dopa or clonidine and insulin hypoglycaemia test) were done. Then the heights of the short students were observed for 1/2-2 years. GHD was diagnosed in 12 cases based on the GH peak levels less than 10 micrograms/L in two provocative tests, whose growth velocity was slower than that for students of the same age and sex. Of these subjects with GHD, total GHD (GH less than 5 micrograms/L) was present in 7 and partial GHD (GH = 5-9.9 micrograms/L) in 5. The 12 GHD students (male 9, female 3) aged 8.9-15.7 years accounted for 1/8,646 in the total surveyed students. The male and female GHD accounted for 1/5,777 and 1/17,253 in the total males and females respectively.

[The characterization of mutant No. 68 from midecamycin producing strain S. mycarofaciens 1748]

A stable mutant No. 68 was obtained by treatment of S. mycarofaciens 1748 spores at high temperature. The electromicroscopic examination has shown that the mutant No. 68 and parent strain 1748 both have the spore chains of the spiratype. The spores of both strain are cylindrical in shape. The only difference is that the spores of the mutant No. 68 are of smooth surface, but the 1748 are of thorny. The physiological characteristics of both strains are also very similar with slight differences in utilization of few carbon sources and in cultural characters in few medium. Feeding experiment has shown that the mutant No. 68 was blocked in the formation of the macrolide lactone in the midecamycin biosynthetic pathway. This suggested that the mutant No. 68 might be a polyketide synthase genes deficient mutant. The ability of the mutant No. 68 to convert spiramycin into 4"-propionylspiramycin indicated that the mutant No. 68 contained the midecamycin 4"-propionyltransferase and could be used for microbial bioconversion of spiramycin into 4"-propionylspiramycin.

Organic anion transport in HepG2 cells: absence of the high-affinity, chloride-dependent transporter

In previous studies, we identified a 55 kD organic anion-binding protein in liver cell sinusoidal plasma membrane subfractions. Other investigators identified another 55 kD bromosulfophthalein/bilirubin binding protein on the surface of rat hepatocytes and HepG2 cells and suggested that this protein served as a transporter for these ligands. In this study, transport of 35S-sulfobromophthalein by the human hepatoma cell line, HepG2, was quantified in the presence and absence of bovine serum albumin to further clarify the possible function of these plasma membrane binding proteins. In contrast to results in normal rat hepatocytes, virtually no uptake of 35S-sulfobromophthalein by HepG2 cells in the presence of bovine serum albumin was found. In the absence of albumin, HepG2 cells expressed temperature-dependent uptake of 35S-sulfobromophthalein. However, the high-affinity Cl(-)-dependent sulfobromophthalein transport that characterizes normal rat hepatocytes was absent, as indicated by an approximately 95-fold lower affinity and 170-fold higher capacity of HepG2 cells for sulfobromophthalein compared with previous results with rat hepatocytes. These results suggest that 55 kD sulfobromophthalein/bilirubin-binding protein on the liver cell surface differs from organic anion-binding protein and is not responsible for sulfobromophthalein extraction in the presence of albumin, although it may play some role in lower affinity transport by cells. Immunoblot analysis and metabolic labeling of HepG2 cells demonstrated synthesis of organic anion-binding protein. However, light microscopic immunocytochemistry and immunoprecipitation of surface iodinated rat hepatocytes and HepG2 cells with antibody to a recombinant organic anion-binding protein fusion protein indicated absence of organic anion-binding protein on the surface of HepG2 cells.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro cytotoxicity against fresh human tumors and P388 leukemia predicts the differential in vivo activity of a series of anthracene anticancer drugs

To date, random anticancer drug screening has proven to be relatively inefficient and non-specific with respect to selecting active compounds for most tumor types (except for leukemia/lymphoma). Although large numbers of compounds from diverse sources were evaluated for many years in the P388 mouse leukemia model, only a few clinically useful drugs have been identified by this in vivo screening method. Thus, there is intense interest in the development of more effective in vitro screening models for new anticancer drugs. In the present paper we have compared the discriminating power for fresh human tumors from patients, human tumor cell lines developed from 11 patients and murine P388 leukemia in tumor colony forming assays as indicators of cytotoxicity for a series of anthracene antitumor agents. Two of a series of 21 novel bisantrene analogs, R6 (N,N1-bis[2-(dimethylamino)ethyl]-9,10-anthracene-bis(methylamine)) and R26 (N,N1-bis(1-ethyl-3-piperidinyl)-9,10-anthracene-bis(methylamine] produced significant cytotoxicity against the 11 human tumor cell lines and were therefore selected for additional in vitro and in vivo studies. R26 was specifically selected for further testing since it had similar in vitro potency as mitoxantrone, but showed no cross-resistance against mitoxantrone-resistant WiDr colon or doxorubicin-resistant 8226 myeloma cell lines. In contrast to the cell line data, only of the 22 fresh human tumors showed significant in vitro sensitivity (i.e. less than 50% survival of tumor colony forming units) to either R6 or R26 tested at high concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidemic non-A, non-B hepatitis in Xinjiang. Clinical and pathologic observations

131 cases of epidemic hepatitis from two villages in Xinjiang, were admitted to the provisional infectious diseases hospital from February to April 1987. In 125 (95%) patients neither anti-HAV IgM nor anti-HBc IgM were positive. 118 (90%) were drinking water from a local stream of the Hotan River. The study was conducted on 125 patients aged from 5 to 90 years, with a mean of 26.4 years. There were slightly more males than females, a ratio of 1.5 to 1. The incubation period was roughly estimated to be 17 to 37 days (mean 24.8 days). All subjects were jaundiced. 12 patients (including 6 pregnant women) had cholestatic symptoms. Except one woman who died of postpartum bleeding, all patients ran a benign course without fulminant hepatic failure. Pathologic changes of liver biopsies from 35 cases included lobular damage and inflammation, ballooned hepatocytes with clear cytoplasm and delineated cell membrane which were named "clear cell". There were cholestasis of different degrees in the acute icteric stage and fatty changes in the convalescent stage. It was seen under the electron microscope that the livers of 8 cases had neither tubular structure nor sponge-like inclusions, but had nuclear changes including curled edge of nuclear membrane and nuclear heterochromatin condensed in masses. Liver biopsies were repeated in 7 cases followed up for 6-13 months, and hepatohistology was normal in 5. Of the other two cases there was one of each.

Clinical trial with somatonorm in idiopathic growth hormone deficiency in children

This article reports the efficacy and safety of treatment with Somatonorm in 9 children with idiopathic growth hormone (GH) deficiency in China. The growth velocity increased from 2.6 +/- 0.2 cm/year before treatment to 10.7 +/- 0.5 cm/year at the end of 1-year treatment. The increment of human growth hormone (hGH) level and area under the response curve above the baseline level were larger after one injection of Somatonorm at the dose of 0.1 IU/kg sc than that of 0.17 IU/kg im. Increments of delayed bone age were not significant. There was no correlation between the increase of height growth velocities and the serum Somatomedin-C (SMC) levels during hGH therapy (r = -0.055). Blood sugar levels and blood alkaline phosphatase concentrations increased significantly after therapy. There were no significant side effects. Serum T4 levels of 3 patients dropped below normal after treatment. Serum anti-hGH antibody appeared at 3-12 month in 2 patients, but it did not attenuate the growth velocity.

Modification of the clonogenic assay for the detection of lymphokine activated killer cell activity

The soft agar clonogenic assay using [3H]thymidine uptake as an endpoint was adapted for the detection of human LAK activity against the Daudi lymphoma cell line and human tumor cells obtained by biopsy. Using Daudi cells as the target population the modified agar assay was more sensitive than the conventional 4 h 51Cr release assay. Use of a single layer agar assay allowed the assessment of LAK cytotoxic/cytostatic activity against Daudi lymphoma cells after cell to cell contact, while a two layer system permitted evaluation of the role of soluble mediators in LAK/target cell interactions. This study shows that LAK cells can either kill or inhibit the proliferation of Daudi cells by two mechanisms: one which requires cell-to-cell contact, and a second via soluble mediators. As determined by the use of neutralizing antisera, the soluble factor(s) are not tumor necrosis factor and interferon-gamma. Of the nine individual human tumor samples obtained by biopsy. 89% were sensitive to allogeneic LAK cells when the two populations were admixed. Of these nine tumors 44% were inhibited by LAK-derived soluble factors. The soft agar assay system should serve as a useful tool for determining the sensitivity of human tumors to LAK cells and for studying the mechanisms of LAK anti-tumor activity.

Effects of granulocyte-macrophage colony-stimulating factor on in vitro growth of human solid tumors

Solid tumor biopsies from 33 patients were tested in vitro to evaluate the growth modulatory effects of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF). In 29 of 33 studies (88%), addition of GM-CSF either had no effect on in vitro growth, or induced growth inhibition. While significant growth inhibition was observed in 10 studies, marked inhibition was only observed in three studies. However, all dose-response curves were usually flat, suggesting indirect effects. Moderate growth stimulation was observed in four instances, which may have been due to residual granulocyte-macrophage progenitors within the biopsies. We conclude that GM-CSF has little or no growth-modulatory effect on most nonhematopoietic neoplasms. The primary role of GM-CSF in patients with solid tumors appears to be in prevention or reversal of myelosuppression associated with therapy. Thus, while GM-CSF seems unlikely to have a role in monotherapy of cancer, it is also unlikely to have its utility compromised by enhancement of tumor growth.

Superconducting Gap in Bi-Sr-Ca-Cu-O by High-Resolution Angle-Resolved Photoelectron Spectroscopy

Detailed studies indicate a superconducting gap in the high-temperature superconductor Bi(2)Sr(2)CaCu(2)O(8). Photoemission measurements with high energy and angle resolution isolate the behavior of a single band as it crosses the Fermi level in both the normal and superconducting states, giving support to the Fermi liquid picture. The magnitude of the gap is 24 millielectron volts.