Micrococcal nuclease as a probe for bound and distorted DNA in lac transcription and repression complexes

Micrococcal nuclease (MNase) is used to probe the structure of transcription and repression complexes at the lac regulatory region in vitro. Both the lac operator, 01, and the pseudo-operator, 03, are found to be protected from MNase digestion by the lac repressor on supercoiled DNA, and hypersensitive sites appear on both strands around nucleotide (nt) -26 between 01 and 03. This hyperreactive site is coincident with the site of the DNA kink shown previously to form within a loop caused by simultaneous repressor binding to 01 and 03. MNase hypersites are also observed both upstream from cAMP receptor protein (CRP) and downstream from bound RNA polymerase in open promoter complexes. In both open and closed complexes the binding of polymerase partially protects the backbone from MNase attack. Catabolite activator protein is shown to be required for both closed and open complex formation. Taken together with previous footprinting data, the results suggest that lac transcription complexes involve DNA bent towards a protein core consisting of RNA polymerase and catabolite activator protein.

Analysis of cytotoxic T cell precursor frequencies directed against individual HLA-A and -B alloantigens

We describe here a limiting dilution analysis to determine cytotoxic T lymphocyte precursor (CTLp) frequencies against individual HLA-A or -B antigens. This assay is reproducible and showed that the CTLp frequency of an individual remains stable with time. Significant variations in CTLp frequency against the same alloantigen were found in different individuals and even in monozygotic twins, showing that these differences were not (completely) genetically determined. Within an individual, a wide range of CTLp frequencies can be found against different allo-antigens. Serologically cross-reactivity seems not to interfere in this assay. This LDA is a practicable tool for a systematic analysis of CTLp response against selected individual HLA-A or -B antigens and can be used for the selection of HLA mismatched donors for transplantation patients.

Pathogenetic role of anti-vascular endothelial cell antibodies in systemic lupus erythematosus

In order to study the relationship between vascular endothelial cell (VEC) antigen system and systemic lupus erythematosus (SLE), including lupus nephritis, Terasaki's microcytotoxicity test and indirect immunofluorescence were used to detect anti-VEC antibody. VEC was identified by electron microscopy. Sera of 21 SLE patients and of 100 healthy donors were examined. Among the 21 SLE patients evaluated, 17 had kidney injury and 13 were in active stage SLE. Results showed that anti-VEC antibody was found in 76.2% of 21 SLE patients, while only 1% of the controls were positive (P less than 0.05). This antibody was detected in 84.6% of patients in active stage SLE and in 62.5% of patients in inactive stage (P greater than 0.05). In patients with and without kidney injury, it was detected in 82.4% and 50%, respectively (P greater than 0.05). These data show that anti-VEC antibody does exist in the sera of SLE patients, the presence of which is closely related to SLE onset and is independent of whether the patient is in active stage of SLE or has kidney injury. In summary, our data suggest that anti-VEC antibody may be one of the triggering factors in the vasculitis of SLE. It is proposed that renal VEC may act as a target cell which can be attacked by anti-VEC antibody to constitute an in-situ immune complex formation in the kidney, leading to lupus nephritis.

Benzodiazepine analogues L365,260 and L364,718 as gastrin and pancreatic CCK receptor antagonists

We examined the ability of the recently described 3-(benzoylamino)benzodiazepine analogue L365,260 and the 3-(acylamino)benzodiazepine analogue L364,718 to distinguish gastrin from pancreatic cholecystokinin (CCK) receptors. Neither L365,260 nor L364,718 when present alone (1 microM) caused stimulation of amylase release from guinea pig pancreatic acini or caused contraction of smooth muscle cells from guinea pig stomach. Each analogue inhibited CCK-stimulated amylase release, gastrin-17-I-stimulated smooth muscle contraction, binding of 125I-Bolton-Hunter-cholecystokinin octapeptide (125I-BH-CCK-8) to pancreatic CCK receptors, and binding of 125I-gastrin-17-I to gastrin receptors on pancreatic acini. L365,260, (Ki, 7.3 +/- 0.8 nM) was 50-70 times more potent than L364,718 at inhibiting binding of 125I-gastrin to pancreatic acini or gastrin-stimulated smooth muscle contraction. In contrast, L364,718 (Ki, 4 +/- 1 nM) was 145-200 times more potent than L365,260 at inhibiting binding of 125I-BH-CCK-8 to pancreatic acini or CCK-stimulated amylase release. Neither L364,718 nor L365,260 distinguished between high- and low-affinity CCK binding sites. L365,260 and L364,718 did not inhibit binding of radiolabeled vasoactive intestinal peptide, secretin, bombesin, substance P, or N-methylscopolamine to pancreatic acini. These results demonstrate that, in contrast to other gastrin-CCK receptor antagonists described, L365,260 is a selective gastrin receptor antagonist having an 80-fold higher affinity for gastrin than pancreatic CCK receptor, whereas L364,718 has a 125-fold higher affinity for pancreatic CCK receptors. Because of the selectivity of these two antagonists the involvement of CCK and gastrin in various physiological processes can be differentiated even when both receptors occur on the same cell.

Gamma-glutamyl transpeptidase activity in superficial exfoliated cells during hamster buccal pouch carcinogenesis

The study of gamma-glutamyl transpeptidase (GGT) activity in transformed tissues has conventionally involved the killing of an animal or excision of the lesion, preventing longitudinal study. Oral exfoliative cytology allows longitudinal examination; however, it has been shown to be an unreliable criterion of malignancy. GGT activity has been demonstrated histochemically to involve the full thickness of the epithelium, including the keratin layer during carcinogenesis of hamster buccal pouch epithelium. This study correlates the GGT-stained foci in tissue sections and the proportion of GGT-positive cells in a superficial smear during a 13-week regime of tri-weekly topical application of 7,12-dimethylbenz[a]-anthracene (DMBA) in mineral oil. GGT-positive cells were detected in smears 3 weeks after application of the carcinogen, coincident with GGT-positive foci in tissue sections involving the keratin layer. The proportion of GGT-positive cells in each experimental period increased during the first 7 weeks of the experiment and plateaued thereafter. The number of GGT-positive foci in tissue sections in each experimental period also increased during the experiment. GGT activity was not detected in either smears or tissue sections of untreated or mineral oil treated mucosa. The correlation between the proportion of GGT-positive cells in smears and GGT-positive foci in tissue sections suggest the possibility of studying the GGT activity in an experimentally induced lesion without its elimination. Furthermore, oral exfoliative cytology using GGT staining may be useful in detecting precancerous lesions clinically.

[Retinal function test of eyes with opaque refractive media]

The characteristics of the laser interference fringes of opaque lenses were studied by the laser speckle method. After studies with the opaque lenses in the laboratory, the method was employed in the clinic. The preoperative laser interference fringe visual acuities were compared with the postoperative corrected visual acuities in 65 eyes with mature cataract and 8 eyes with cornea opacities. The authors concluded that the laser speckle interferometry estimated the retinal function of eyes with opaque refractive media quantitatively and it demonstrated practical value in the clinic.

The effect of edible black tree fungus (Auricuaria auricula) on experimental atherosclerosis in rabbits

The effects of edible black tree fungus (BFF) compared with aspirin on serum lipid level and experimental atherosclerosis and thrombosis in rabbits were studied. The results showed that total serum cholesterol and B-lipoprotein of the BTF group were significantly decreased (P less than 0.01) than the aspirin group and the group with neither BTF nor aspirin. There were less aortic atherosclerotic plaque and intramyocardial arterial lumen stenosis in the BTF group. The development of thrombus and platelet aggregation and thromboxane TXB2 level were inhibited both in the BTF and aspirin group (P less than 0.01). These findings indicate BTF may be used as a healthy food in preventing atherosclerosis and coronary heart disease, but its mechanism requires further investigation.

Investigation on genetic traits and selection of interspecific somatic hybrid progenies in tobacco

The interspecific somatic hybrid plants were produced in 1980 by protoplast fusions between N. tabacum and N. rustica, and N. tabacum and N. glauca. The results of this study on the genetic traits and selection of the hybrid progenies for seven years showed that the performances of the somatic hybrids (SH) were typical intermediate forms of the two species involved in each somatic hybridization, and that segregation began in SH3 and (SH)BC2 generations (the SH1 backcrossed to N. tabacum twice). However, stable lines and male sterile lines from SH1 until the present, were also obtained. The fertilities of the hybrid progenies were generally poor. The characteristics of the recurrent parent were accumulated, and the chromosome numbers of the hybrid plants were gradually decreased as the number of backcrossing generations increased. Some new types of tobacco with certain commercial values have been selected for used in the present study. The conclusion reached, based on our results, is that the somatic hybridization technology has now been successfully utilized to create unique breeding lines of tobacco, and represents a powerful, new tool for crop improvement.

Central neurotensin affects rat gastric integrity, prostaglandin E2, and blood flow

The aim of this study is to define the effect(s) of centrally administered neurotensin (NT) on gastric mucosal integrity, prostaglandin E2 (PGE2) generation, and blood flow during stress induced by cold-water restraint (CWR) in rats. Intracerebroventricular (icv) NT reduced macroscopic and microscopic damage. The former effect was dose dependent and was totally blocked by indomethacin pretreatment. Gastric mucosal PGE2 increased 27 and 30% at 30 and 60 min, respectively, in nonrestrained rats given icv NT. PGE2 generation was reduced in control rats during CWR but was maintained in CWR rats treated with icv NT. Gastric mucosal blood flow (GMBF) was significantly reduced in control rats during CWR. Mucosal blood flow was maintained at nonrestraint levels in the presence of icv NT during CWR; however, this effect was abolished by parenteral indomethacin pretreatment. Similarly, intravenous 16,16-dimethyl-PGE2 (200 micrograms.kg-1.h-1) maintained GMBF of non-CWR levels as well as preventing the macroscopic damage normally associated with CWR. These data suggest a protective role for central NT on the gastric mucosa, mediated, at least in part, by PGE2 generation and gastric mucosal blood flow.

Effect of Mycobacterium tuberculosis-derived sulfolipid I on human phagocytic cells

Experiments were performed to determine the effects of Mycobacterium tuberculosis-derived sulfolipid I on phagocytic cells. Sulfolipid I was taken up in significant amounts by human neutrophils and in lesser amounts by monocytes and lymphocytes. Superoxide (O2-) production by neutrophils was significantly increased by sulfolipid I, but the rate of production was slower than that reported previously for other stimuli. The optimal concentration of sulfolipid I for stimulation of O2- production was 27 micrograms/ml, while higher concentrations produced less. At substimulatory levels sulfolipid I caused enhancement of O2- release from neutrophils when it was subsequently stimulated by other agents. Nonadherent monocytes from most normal donors failed to produce O2- when treated with sulfolipid I; however, adherent monocytes pretreated with gamma interferon did produce O2- with sulfolipid I stimulation. Priming for an enhanced oxidative response of activated monocytes was also observed. These sulfolipid I-induced changes in phagocytic cell function may be important in altering the ability of phagocytes to respond effectively to M. tuberculosis and may also cause exaggerated inflammatory responses.

An analogue of substance P with broad receptor antagonist activity

[DPro4,DTrp7,9,10]Substance P-4-11 functions as a substance P receptor antagonist in several different systems. Because some analogues of substance P can function as receptor antagonists for bombesin as well as substance P, we tested [DPro4,DTrp7,9,10]substance P-4-11 for its ability to modify the interaction of various pancreatic secretagogues with their receptors in dispersed acini from guinea pig pancreas. [DPro4,DTrp7,9,19]Substance P-4-11 did not stimulate amylase secretion and did not alter the stimulation of amylase secretion caused by secretin, vasoactive intestinal peptide, calcitonin gene-related peptide or carbachol, but did inhibit the stimulation of amylase secretion caused by substance P, bombesin or cholecystokinin. With substance P, bombesin and cholecystokinin, [DPro4,DTrp7,9,10]substance P-4-11 caused a parallel rightward shift in the dose-response curve for stimulation of amylase secretion with no change in the maximal response. Schild plots of these results gave straight lines with slopes that were not significantly different from unity. [DPro4,DTrp7,9,10]Substance P-4-11 inhibited binding of 125I-labeled substance P, 125I-[Tyr4]bombesin and 125I-cholecystokinin octapeptide over the same range of concentrations as that in which it inhibited biologic activity of each of these peptides. Half-maximal inhibition of binding of 125I-substance P occurred with 4 microM, of 125I-[Tyr4]bombesin with 17 microM and of 125I-cholecystokinin octapeptide with 5 microM. With each radiolabeled peptide the value of Ki for inhibition of binding by [DPro4,DTrp7,9,10]substance P-4-11 was not significantly different from the corresponding value of Ki calculated from the appropriate Schild plot. The present results indicate that [DPro4,DTrp7,9,10]substance P-4-11 is a competitive antagonist at receptors for substance P, for bombesin and for cholecystokinin. Thus, these receptors must share a common peptide recognition mechanism even though they interact with agonists that have no obvious structural similarity.

Intracellular injection of Ca2+ chelator does not affect spike repolarization of cat spinal motoneurons

Both intra- and extracellular injections of tetraethylammonium (TEA) prolonged the spike repolarization of motoneurons in the spinal cord of cats under pentabarbitone anaesthesia, but did not depress the afterhyperpolarization (AHP). Intracellular injections of EGTA and the fast-acting Ca2+ chelator, BAPTA, greatly depressed the AHP, but the spike shape remained unchanged. Extracellular applications of Cd2+ had similar effects. These observations suggest that a Ca2+-dependent K+ outward current is not a major mechanism of spike repolarization in motoneurons.

Effects of cyclophosphamide and a metabolite, acrolein, on Naegleria fowleri in vitro and in vivo

Mice challenged intranasally with Naegleria fowleri died of primary amoebic meningoencephalitis. Mice given 30 mg of cyclophosphamide per kg of body weight daily for 10 days starting 2 days before challenge were protected. Neither cyclophosphamide nor serum from cyclophosphamide-treated mice inhibited N. fowleri in vitro. A metabolic product of cyclophosphamide, acrolein, inhibited growth and enflagellation of N. fowleri. Acrolein at 40 microM was amoebicidal. Acrolein injured starved cells and amoebae at 5 degrees C and growing N. fowleri.

Interference filters as nonlinear decision-making elements for three-spot pattern recognition and associative memories

Simple patterns consisting of three spots (V and Gamma) have been recognized by dividing, shifting, and recombining beams onto bistable ZnS interference filters. This experiment demonstrates AND-gate operation, cascading, and a moderate amount of parallelism, but a laser power of several watts was required and the response times were several milliseconds. An associative memory for fingerprint identification has been constructed using a VanderLugt correlator and an interference filter as a reflective thresholding device.

[Luteinizing hormone-releasing hormone (LRH) agonist in the treatment of breast cancer, osteosarcoma and prostate carcinoma--analysis of 12 patients]

This paper first reports the results of 12 patients with sex hormone-dependent neoplasms, including 9 women with breast cancer, 2 men with osteosarcoma and 1 man with prostate carcinoma, treated by LRH agonist, (D-Ala6, des-Gly-NH2(10))-LRH-ethylamide (LRH-A) 100-200 micrograms, IM, QD. After 15-30 days of administration, the concentrations of plasma mean estradiol, progesterone, testosterone, serum luteinizing hormone and follicle-stimulating hormone were lowered significantly in the peripheral blood of all patients, associating with improvement of the patients' general condition and reduction of the tumors and/or metastatic foci. No serious side effects were observed except vaginal irregular bleeding in isolated patients. Three patients died and the others were alive in follow-up of 4-30 months. The results suggest that LRH-A be useful in the treatment of the sex hormone-dependent tumors and worth further study.

Proliferative activity of murine mammary epithelium as affected by dietary fat and calcium

Dietary fat and calcium have been found to affect significantly the proliferative status of the mammary glands. Female mice (3-week-old C57BL/6J) were given either a low or high corn oil diet (3 or 30% by weight). One, 2, or 4 weeks after the dietary intervention the animals were given injections of [3H]thymidine and/or colchicine; 2 h later their thoracic mammary glands were removed and processed for histology and autoradiography. Animals on the high corn oil diet had an increased labeling index of both terminal ducts and mature ducts compared to the control group at each time (i.e., 10.1 +/- 2.1 versus 4.8 +/- 0.9% at 2 weeks). This effect of a high corn oil diet was evident on the mammary glands of animals at various ages. Animals on a high beef tallow diet also had a high labeling index. This effect of a high fat diet appeared to be reduced by dietary calcium. The labeling index for terminal ducts of animals on high corn oil diet decreased from 14.1 +/- 3.8, 11.9 +/- 3.4 to 8.5 +/- 1.8 and high beef tallow from 13.6 +/- 3.6, 11.4 +/- 0.7 to 9.5 +/- 1.3 for calcium levels of 0.1, 0.5, and 1.0%, respectively. Mitotic indices followed the same trend. These studies demonstrate that a high fat diet affects the proliferative status in the mouse mammary glands in a short period of time and that this effect can be reduced by dietary calcium.