Optical scattering and absorption by branched chains of aerosols

We utilize the Volume Integral Equation Formulation (VIEF) and the method of moments to calculate the electromagnetic scattering and absorption of aerosol particles with branched-chain structures. Two kinds of polarization of the incident electromagnetic wave were considered: the cross- and end-fire polarizations. The numerical results of internal electric field distribution, absorbed power, and extinction and scattering cross sections, obtained from the VIEF, show excellent agreement with the Mie theory for the special case of spherical particles. Comparison between the results of the VIEF and Iterative Extended Boundary Condition Method for very long oriented (elongated) chains of particles also showed good agreement. After validating the accuracy of the VIEF, the absorption characteristics of three branched-chain structuressimulated from microscopic pictures of coagulated smoke aerosol particles were calculated. Results showed that the ratio of absorption in the two polarization cases, P(cross-fire)/P(end-fire), for very long oriented chain structures is as high as a factor of 4 at lower frequencies (lambda =10microm). While in the higher frequency (lambda = 0.5-microm) case, the ratio Of P(cross-fire)/P(end-fire) is reduced to 2.0. For branched-chain structures, the ratio Of P(cross-fire)/P(end-fire) decreased with the increase in the number of the side branches. These observations show that the frequency, polarization, and structure factors play important roles in determining the optical characteristics of branched chains of aerosol particles.

[The anatomical study on the branches of the femoral artery (II). Comparison with the findings of Adachi's classification]

The authors studied the mode of three main branches of the femoral artery (deep femoral, medial circumflex femoral and lateral circumflex femoral artery) in 179 Japanese cadavers during dissecting practice at Gifu University in the last four years. The findings were as follows; Two hundred and seventeen sides in the 352 sides (61.7%) belong to Type I of Adachi's classification on variations in the arrangement of the branches of the femoral artery. Forty-one sides (11.6%) belong to Type II, 55 sides (15.6%) to Type III, 7 sides (2.0%) to Type IV, 8 sides (2.3%) to Type V, 4 sides (1.1%) to Type VI, 5 sides (1.4%) to Type VII and 15 dises (4.3%) to other types. Five cases in 15 sides which belong to other types have been reported in our previous study (Emura et al. 1985). In 3 cases out of 10 sides the deep femoral-medial circumflex femoral trunk, and the ascending and descending branches of the lateral circumflex femoral artery arise from the femoral artery, respectively. In one case out of 10 sides the deep femoral-lateral circumflex femoral trunk and the medial circumflex femoral-inferior epigastric-obturator trunk arise from the femoral artery, respectively. In one case out of 10 sides the lateral circumflex femoral artery and the deep femoral-medial circumflex femoral-inferior epigastric-obturator trunk arise from the femoral artery, respectively. In one case out of 10 sides the medial circumflex femoral-deep circumflex iliac trunk arises from the lateral side of the femoral artery and runs medially behind the femoral artery, and the deep femoral-lateral circumflex femoral trunk arises from the femoral artery. In one case out of 10 sides the deep femoral-ascending (the lateral circumflex femoral artery) trunk, the medial circumflex femoral artery and the deep circumflex iliac-descending (the lateral circumflex femoral artery) trunk arise from the femoral artery, respectively. In one case out of 10 sides the deep femoral-descending (the lateral circumflex femoral artery) trunk, the medial circumflex femoral artery and the ascending branch of the lateral circumflex femoral artery) trunk, the medial circumflex femoral artery and the ascending branch of the lateral circumflex femoral artery arise from the femoral artery, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

[A preliminary study on determining total serum IgE and specific anti-mite IgE antibody in cigarette manufacturing workers]

Total serum IgE and specific anti-mite IgE antibody (IgEAM) were determined in cigarette manufacturing workers with (but not asthma) or without respiratory symptoms (30 cases in each) 16 patients with bronchial asthma, 8 with asthmatic bronchitis and 6 with other respiratory diseases. The total serum IgE level was significantly higher in symptomatic workers (825.8 +/- 22.3 IU/ml) than that of asymptomatic (162.1 +/- 28.0 IU/ml) (P less than 0.001) and patients with other respiratory diseases (P less than 0.05), but was lower than that of patients with bronchial asthma (3310.3 +/- 26.3 IU/ml) and asthmatic bronchitis (2278.4 +/- 25.5 IU/ml) (P less than 0.001). IgEAM was undetectable in all cases except one with asymptomatic worker and one with asthma. The respiratory symptoms in these workers seemed to be related to type I allergic reaction, possibly due to the chemical components in the cigarettes.

A tool for assessing inadequate dialysis

Blood urea nitrogen (BUN) is thought to be a useful marker of the concentration of other solutes that underly the manifestation of uremia. By monitoring quality assurance parameters, 8 out of 57 dialysis patients were found during monthly blood work exams to have BUN greater than 100 mg/dl. An "Inadequate Dialysis Checklist" was designed for hemodialysis and peritoneal dialysis and used to assess all eight patients' treatments. The dialysis was corrected or integrally modified. As a result, the number of patients with BUN greater than 100 mg/dl decreased. These checklists can be useful for case managers to assess and evaluate dialysis variables.

Enhancement of interferon-induced 2-5 oligoadenylate synthetase activity by retinoic acid in human histiocytic lymphoma U937 cells and WISH cells

The effect of retinoic acid (RA) on the level of interferon (IFN)-induced 2-5 oligoadenylate (2-5A) synthetase activity was examined in human histiocytic lymphoma U937 cells and WISH cells** in order to ascertain the role of this polymerase in interaction between IFNs and RA. Cultures containing both IFNs (1-100 U/ml) and RA (0.1-10 microM) consistently had higher levels of enzyme activity than corresponding cells treated with IFN alone and this was true for all three types of IFNs in both cell lines. The potentiating effect of RA was dose- and time-dependent and under optimal conditions, the induction of the synthetase was synergistic between IFN-beta (10-100 U/ml) and RA (0.1-10 microM). Furthermore, pretreatment (but not posttreatment) with RA followed by subsequent treatment with IFNs preferentially induced higher levels of enzyme activity in U937 cells but not in WISH cells. In addition, our results indicated that the modulating effect of RA on IFNs did not involve interaction at the receptor level and the level of enhancement of 2-5A synthetase activity was not in parallel with either cell-growth arrest or promotion of differentiation. Lastly, the present study raises the possibility that interactions between IFNs and RA, in either a synergistic or antagonistic manner, may be mediated through amplification of the 2-5A system.

Differential modulating effects of retinoic acid on interferon antiviral activity

The effect of retinoic acid (RA) on the antiviral activity of interferons (IFNs) alpha and beta in the U937 and WISH cells was examined to ascertain whether or not RA could reduce the effectiveness of IFN-induced resistance to viral infection. Our results indicate that in the U937 cells, RA (0.1-1.0 microM) had neither enhancing nor suppressive effect on the antiviral activity of IFN-alpha or beta against the Semliki Forest virus (SFV). However, in the WISH cells, RA had different effects on IFNs alpha and beta. Thus, while RA (0.1-50 microM) invariably suppressed the activity of IFN-alpha, it enhanced the action of IFN-beta at low dose (0.1-1.0 microM) but became suppressive at higher concentrations (greater than or equal to 10 microM). Furthermore, higher antiviral activity was consistently obtained when RA (0.1-10 microM) was added prior to either IFN-alpha or IFN-beta comparing to cultures with IFN alone. In addition, direct correlation between antiviral activity and the amplitude of 2-5 oligoadenylate (A) synthetase activity was not observed. These results suggest that modulation of IFN antiviral activity by RA varies with different systems and is dependent on the sequence of treatment.

Percutaneous ultrasound-guided fetal blood sampling: experience in the first 100 cases

Percutaneous ultrasound-guided fetal blood sampling was performed on 100 pregnancies with various fetal problems. Our technique involved the use of a 45 degree needle guide attached to a sector probe. Their gestational ages ranged from 17-38 weeks, mostly over 20-35 weeks. Seventy percent of cases were successful at the first sampling and 33% of cases had bleeding from the punctured cord. In 43 cases, a positive diagnosis was established after ultrasound-guided fetal blood sampling, including 25 Hemoglobin Bart's hydrops fetalis, 2 beta-thalassemia major, 1 hemophilia, 1 rubella infection, 1 syphilis and 13 chromosome aberrations. There were 33 survivors in this series. Seven anomalous fetuses ended in intrauterine deaths. Sixty cases resulted in neonatal deaths after spontaneous or induced labors. No fetal loss occurred in 25 normal fetuses. One fetal loss was probably related to the procedure (fetal loss rate 1/100). No immediate fetal death after sampling procedure was noted. In conclusion, ultrasound-guided fetal blood sampling had reasonable safety and technical feasibility. More common use of this technique in fetal investigations is justified and expected.

[Exploration between shen and ear by auditory determination in patients with renal disease]

Hearing determination of 51 cases had been made to observe and explore the TCM pathogenic relation between the collateral channels of Shen and ears. Model 51A-T72N pure tone auditional determinator was used. For each case, routine auditional determination was made after rest in bed quietly for an hour after breakfast. The determinating results were divided into normal (average hearing loss less than 15dB), low frequency, high frequency and plain-typing hearing loss.

RESULTS

Among the 51 cases, 8 cases were normal hearing (15.7%), the hearing loss cases were 43 (84.3%); 30 cases were double-ear hearing loss (58.8%); 13 cases were single ear hearing loss (25.5%). Cases of renal diseases frequently occurred among the young (in this group, average age was 29.5 years). Such high incidence was obviously non-physiological, but related to the renal disease itself. More serious hearing damage were seen and were in high frequency. Whether or not it was caused by hypoalbuminaemia, oedema and deprivation in blood vessel leading to disorder of circulation of sound sensitizen, or accumulation of toxin owing to renal dysfunction, or changing composition of endolymph influencing the hearing bristle cells, further research should be done in the near future.

Effects of hypergravity environment on the parathyroid gland of the isoproterenol-treated hamster

The ultrastructure of the parathyroid glands of hamsters subjected to 5 g environment after an intraperitoneal injection of isoproterenol was studied. In the isoproterenol-treated hamsters exposed to hypergravity environment, the Golgi complexes, cisternae of the granular endoplasmic reticulum and lipid droplets were significantly increased and secretory granules were significantly decreased compared with those of the control group. In addition, many chief cells contained numerous prosecretory granules in the Golgi areas and several secretory granules were situated close to the plasma membrane of the chief cells. These results suggest that the synthesis and release of parathyroid hormone may be markedly stimulated in the parathyroid glands of the isoproterenol-treated hamsters exposed to hypergravity environment.

Umbilical artery flow velocity waveforms in fetuses dying with congenital anomalies

Absent or reversed diastolic component in umbilical artery (UA) flow velocity waveform was observed in eight fetuses with major malformations. Because of the uncorrectable fetal conditions or the parents' reluctance to terminate the pregnancy, no interventions were undertaken and eventually all eight fetuses died in utero. The interval between the abnormal waveform recording and fetal death was between 1 and 7 days (mean 3.6 days). In two fetuses with abnormal diastolic flow, analysis of umbilical vein blood obtained by ultrasound-guided sampling revealed moderately severe acidosis and hypoxia (pH 7.228 and 7.241, PCO2 47.5 and 46.9 mmHg; PO2 14.6 and 14.7 mmHg, respectively). Our observation suggests that once the diastolic component of UA flow velocity waveforms becomes absent or reversed, the fetus is in a state of hypoxia and acidosis and fetal death is impending. This limited experience may help in formulating clinical management when using UA flow velocity waveforms in the monitoring of high-risk fetuses.

Umbilical vein blood flow measurement in nonimmune hydrops fetalis

Twenty-five measurements of fetal umbilical vein blood flow were performed in 22 cases of nonimmune hydrops fetalis using real-time and pulsed Doppler duplex ultrasound. The umbilical vein diameter, blood velocity, and blood flow in fetuses with hemoglobin Bart's hydrops fetalis were usually higher than those in fetuses with hydrops fetalis from other causes. Umbilical vein blood flow measurement appears to be an effective technique for differentiating hemoglobin Bart's from non-Bart's hydrops in this series. This hemodynamic characteristic of umbilical vein blood flow may be helpful in determining the etiology of nonimmune hydrops fetalis.

[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.

Immunocytochemical localization of parathyroid hormone in hamster parathyroid gland

The immunocytochemical localization of parathyroid hormone was examined in the hamster parathyroid gland by using the protein A-gold technique. Protein A-gold particles were concentrated over secretory granules, large secretory granules thought to be storage granules and Golgi vacuoles. No protein A-gold particles were detected over large vacuolar bodies and cisternae of the granular endoplasmic reticulum.

Rapid karyotyping in fetuses with abnormal sonogram

Prenatal karyotyping of fetuses having an abnormal sonogram was undertaken in 27 pregnancies between 17 and 39 weeks, using fetal blood obtained by percutaneous umbilical cord blood sampling under ultrasound guidance. Eight chromosomal abnormalities (29.7%) were detected, including 45, X (2 cases), trisomy 21(1 case), 46, XY,-13,+t(13,13) (1 case), 47, XX,+18(3 cases), 47, XXY (1 case). Nineteen fetuses had a normal karyotype (46,XX:9 cases, 46,XY:10 cases). The fetal karyotype was available within 72 h and fetal management was planned accordingly. We concluded that in fetuses with an abnormal sonogram, rapid karyotyping using fetal blood obtained under ultrasound guidance had important implications in obstetric and neonatal management and would facilitate genetic counselling.

Growth hormone gene expression in myoepithelial cells directed by various eucaryotic transcriptional regulatory sequences

Mammary gland myoepithelial cells were isolated from cattle and cell lines were established. Cells were plated onto tissue culture dishes with or without collagen. Cells were transfected with bovine growth hormone rDNA containing one of the following eucaryotic transcriptional regulatory sequences: human cytomegalovirus immediate early promoter, simian virus 40 early promoter, mouse metallothionein I promoter and the Rous sarcoma virus long terminal repeat. These sequences were evaluated for their ability to direct recombinant bovine growth hormone DNA expression in myoepithelial cells. The most effective transcriptional regulatory sequences were the cytomegalovirus immediate early and simian virus 40 early promoters.

Percutaneous ultrasound-guided fetal blood sampling in the management of nonimmune hydrops fetalis

Nonimmune hydrops fetalis can be caused by fetal chromosomal, hematologic, cardiac, or infectious conditions. A fetal blood sample obtained from percutaneous ultrasound-guided fetal blood sampling can offer vital information about the underlying cause of nonimmune hydrops fetalis, and perinatal management can be planned accordingly. Ten cases of nonimmune hydrops fetalis were investigated with percutaneous ultrasound-guided fetal blood sampling and subsequent fetal blood analysis. Nine were proved to be Bart's hemoglobin hydrops fetalis, with 78.2% to 99% of Bart's hemoglobin in the fetal blood. Terminations of pregnancy were undertaken immediately, resulting in a lowered maternal morbidity rate. Free cord loops or an intra-abdominal portion of the dilated umbilical vein can be used for percutaneous fetal blood sampling in nonimmune hydrops fetalis when the placental cord insertion is difficult to visualize. Percutaneous ultrasound-guided fetal blood sampling and subsequent fetal blood analysis will eventually play a key role in the management of the puzzling nonimmune hydrops fetalis if the safety of ultrasound-guided fetal blood sampling can be verified by further clinical studies.

Regulation of thrombopoiesis: effects of the degree of thrombocytopenia on megakaryocyte ploidy and platelet volume

We have established a murine model and techniques with which to serially study thrombocytopoiesis after induction of experimental immune thrombocytopenia of variable severity and duration. Bone marrow megakaryocyte ploidy distribution was determined by using unfractionated bone marrow, a polyclonal megakaryocyte-specific probe, and two-color, fluorescence-activated flow cytometry. With these techniques, the modal megakaryocyte ploidy class in normal murine bone marrow was 16N. Serial studies of bone marrow megakaryocyte ploidy after the induction of acute, severe thrombocytopenia (platelet count, less than 0.05 X 10(6) microL) demonstrated no detectable change in the ploidy distribution at 12, 24, and 36 hours after the onset of thrombocytopenia. At 48 hours, the modal ploidy class shifted from 16N to 32N, and the 64N class increased significantly (P less than .001). The ploidy distribution returned to normal 120 hours after the onset of thrombocytopenia. A lesser degree of thrombocytopenia (platelet count reduction to 0.100 to 0.200 X 10(6)/microL) delayed the modal ploidy class shift from 16N to 32N until 72 hours after the onset of thrombocytopenia. Chronic, severe thrombocytopenia (platelet count, less than 0.05 X 10(6)/microL for seven days) resulted in a modal ploidy class shift from 16N to 32N during the thrombocytopenic phase and an enhanced increase in the 64N megakaryocyte class during the recovery phase. Mean platelet volume (MPV) was simultaneously measured on isolated total platelet populations after induction of thrombocytopenia. MPV was significantly increased (P less than .001) as early as eight hours after the onset of acute, severe thrombocytopenia, 40 hours before a shift in the ploidy distribution. Mild thrombocytopenia (platelet count reduction to 0.400 X 10(6)/microL) was not associated with a ploidy shift but did result in a significantly increased MPV (P less than .001). These studies demonstrate that the temporal relationship and magnitude of the effects of thrombocytopenia upon megakaryocyte ploidy distribution are dependent upon the degree and the duration of the thrombocytopenic stimulus and that the effects of experimental thrombocytopenia on platelet volume and megakaryocyte ploidy are dissociated.

Penicillin-binding proteins in Streptococcus faecalis and S. faecium

Penicillin-binding proteins (PBPs) of Streptococcus faecalis NCTC 775, S. faecium NCTC 7171 and an isolate of S. faecium (strain 37) highly resistant to beta-lactam antibiotics were visualised by autoradiography. Five PBPs were detected in S. faecalis NCTC 775 and six in S. faecium NCTC 7171. Additional PBPs could not be found in the resistant isolate of S. faecium. The PBP affinities of beta lactams were compared with MIC values. The affinities of PBPs 3 and 4 of S. faecalis NCTC 775 for penicillin G, ampicillin, cefathiamidine, cephaloridine and cephazolin were related to the sensitivity of the strain to these antibiotics as were the affinities of PBPs 4 and 5 in each S. faecium strain for the beta lactams. It is postulated that PBPs 3 and 4 of S. faecalis NCTC 775 and PBPs 4 and 5 of S. faecium are the relevant target enzymes of the test antibiotics. PBPs 4 and 5 of the highly beta-lactam-resistant S. faecium strain 37 showed proportionally low affinities for the five beta lactams compared to that of the less resistant strain S. faecium NCTC 7171. Decreased affinities of PBPs 4 and 5 may account for the resistance in S. faecium strain 37 to beta lactams. The affinities for PBP 1, 2 and 5 in S. faecalis NCTC 775 and PBPs 1, 2, 3 and 6 in S. faecium were not related to the antibiotic sensitivities.

Sensitivity of human germ-cell-tumor cell lines to human interferons

We examined the sensitivity of four human germ-cell-tumor cell lines exhibiting different stages of differentiation to human interferons (IFNs) in vitro. The cell lines were derived from two embryonal carcinomas (NEC 8 and NEC 14), a choriocarcinoma (IMa), and a yolk-sac tumor (HUOT). Treatment with poly I:C induced IFN production in IMa and HUOT cells, but not in NEC-8 and NEC-14 cells. In the two embryonal-carcinoma cell lines, the addition of IFN-alpha, IFN-beta, and IFN-gamma did not prevent infection by vesicular stomatitis virus and encephalomyocarditis virus. Also, in these two lines, 2-5A synthetase was not induced by the addition of IFN-alpha. In contrast, both IMa and HUOT showed sensitivity to the antiviral action of IFN-alpha and IFN-beta against the two viruses, and 2-5A synthetase was induced by IFN-alpha. IFNs added at doses of up to 1000 IU/ml had no antiproliferative effect on NEC 8, NEC 14, and HUOT, whereas colony formation by IMa cells was greatly suppressed by all three forms of IFN. These results indicate that the production of and sensitivity to IFN are developmentally regulated and are related to the level of differentiation of human germ-cell stem cells.

A new antitumor antibiotic, chounghwamycin A. I. Taxonomy, isolation and characterization

Chounghwamycin A, a new antitumor antibiotic produced by a strain of Streptomyces sp. No. PL-D-5, was isolated and characterized. It appeared to belong to the actinomycin group of antibiotics from physico-chemical studies and has an empirical formula of C63H88N11O21. The antibiotic is extractable into an organic solvent from the fermentation broth, possessing potent antileukemic activity against P388 mouse leukemia in mice and antimicrobial activity against Gram-positive bacteria with MIC values about 0.1-0.4 microgram/ml, but showed no activity on Gram-negative bacteria, yeast and fungi tested.

Enhanced production of human interferon-gamma by the use of a combination of inducers--phytohemagglutinin, picibanil and tumor promoting agent

Phytohemagglutinin (PHA), picibanil (OK432) and tumor promoting agent (TPA) were tested in various combinations for optimal induction of human interferon-gamma (HuIFN-gamma). It was found that the use of a mixture of all 3 inducers resulted in IFN production 2-3 times higher than either PHA (10 micrograms/ml) in combination with TPA (5 ng/ml) or picibanil (10 micrograms/ml) alone. The IFN was produced by T lymphocytes and could be neutralized by specific IFN-gamma antiserum. It was pH 2.0 labile and species specific.

Transferable resistance and aminoglycoside-modifying enzymes in enterococci

Ten isolates of Streptococcus faecalis and two isolates of S. faecium were studied together with an NCTC strain of each species. Antibiotic susceptibility tests showed different patterns of high-level resistance to aminoglycosides. Three S. faecalis strains were highly resistant to gentamicin and other aminoglycosides. By means of a filter membrane technique, transfer of high-level resistance to aminoglycosides was demonstrated from S. faecalis to S. faecalis, from S. faecium to S. faecalis and from S. faecalis to S. faecium, the last of which has not previously been described. Aminoglycoside-modifying enzymes were assayed with radiolabelled cofactors. High-level resistance to gentamicin and other aminoglycosides could be attributed to the production of 2''-O-phosphotransferases, 3'-O-phosphotransferases, 6-O-adenylyltransferases and 6'-N-acetyltransferases. Other resistance mechanisms accounted for resistance in two strains of S. faecalis and one strain of S. faecium that were highly resistant only to streptomycin and one S. faecalis strain that was moderately resistant to all aminoglycosides. A low level of 6'-N-acetyltransferases was detected in the three strains of S. faecium but this did not confer high-level resistance to aminoglycosides and this trait could not be transferred.

Expression of human HPRT in the central nervous system of transgenic mice

Severe deficiency of hypoxanthine phosphoribosyltransferase (HPRT) in man results in the Lesch-Nyhan syndrome, an X-linked neurological disorder characterized by mental retardation, choreoathetosis and a compulsive tendency towards self-mutilation. Although the HPRT gene is normally constitutively expressed in all tissues at low levels, expression is elevated approximately fourfold in several regions of the central nervous system, particularly in the basal ganglia. The relationships between HPRT deficiency, tissue-specific alterations of nucleotide metabolism and the neuropathology of the Lesch-Nyhan syndrome remain unclear. Here we have microinjected recombinant molecules containing human HPRT (hHPRT) complementary DNA, the mouse metallothionein-I (MT-I) promoter and the 3'-untranslated portion of the human growth hormone (hGH) gene into mouse embryos to produce transgenic animals that express hHPRT on induction by cadmium. The hHPRT cDNA in these experiments contained 88 base pairs (bp) of 5'-untranslated and 190 bp of 3'-untranslated sequences, and the full-length coding sequence. We studied the in vivo expression of this MT-hHPRT fusion gene and observed preferential hHPRT expression in tissues of the central nervous system (CNS). This study suggests that sequences within the hHPRT transcript (cDNA) influence CNS expression via increased synthesis or stability of messenger RNA.

Peripheral neuropathies, hepatocellular carcinomas and islet cell adenomas in transgenic mice

The ability to introduce foreign DNA into the genome of mice offers unique opportunities to produce new models of disease process. Recent experiments have shown that integration and expression of simian virus 40 (SV40) T antigen genes and the murine mammary tumour virus (MMTV)-myc genes in transgenic mice can lead to the development of neoplasia in a remarkably tissue-specific manner. In the case of SV40-bearing mice, tumours consistently develop in the choroid plexus. In the accompanying paper, we show that the 72-base pair (bp) enhancer in the SV40 genome is instrumental in directing tumorigenesis to the choroid plexus. However, when the enhancer is deleted from a construction also containing the metallothionein-human growth hormone fusion gene (SV delta e-MGH), an entirely new pattern of pathology results. The present report focuses on transgenic mice carrying this construct; they develop demyelinating peripheral neuropathies, hepatocellular carcinomas and islet cell adenomas.

Expression of human beta-globin genes in transgenic mice: effects of a flanking metallothionein-human growth hormone fusion gene

In an attempt to place a human beta-globin gene in an open chromatin domain regardless of its site of integration in the mouse genome, we microinjected into fertilized mouse eggs a construct in which the human beta-globin gene and a mouse metallothionein-human growth hormone fusion gene were juxtaposed and oriented in opposite directions. Mice that developed from injected eggs and that grew larger than normal were analyzed for human beta-globin mRNA. The globin genes were not expressed in erythroid tissue but were expressed with the same tissue specificity as metallothionein-human growth hormone. These results suggest that sequences which control metallothionein-human growth hormone gene expression are capable of stimulating the expression of a flanking gene in an orientation-independent and tissue-specific manner. As a control for this experiment, we deleted the metallothionein-human growth hormone transcription unit and noted that the human beta-globin gene then was expressed at high levels with erythroid tissue specificity.

Factors affecting the efficiency of introducing foreign DNA into mice by microinjecting eggs

Microinjection of foreign DNA into fertilized mammalian eggs is a convenient means of introducing genes into the germ line. Some of the more important parameters that influence successful integration of foreign DNA into mouse chromosomes are described. The effects of DNA concentration, size, and form (supercoiled vs. linear with a variety of different ends) are considered as well as the site of injection (male pronucleus, female pronucleus, or cytoplasm) and buffer composition. The optimal conditions for integration entail injection of a few hundred linear molecules into the male pronucleus of fertilized one-cell eggs. Under these conditions about 25% of the mice that develop inherit one or more copies of the microinjected DNA. The overall efficiency also depends on the choice of mouse strains; for example, generating transgenic mice that express foreign growth hormone genes is about eight times easier with C57/BL6 X SJL hybrid mice than with inbred C57/BL6 mice.

Erythroid-specific expression of human beta-globin genes in transgenic mice

Transgenic mice carrying human beta-globin genes were produced by microinjecting linear DNA molecules containing cloned beta-globin genes with up to 4300 bp of 5'-flanking sequence and 1700 bp of 3'-flanking sequence. Most (15 of 20) of these transgenic mice expressed the human beta-globin genes in blood cells and the level of expression in some mice was comparable with that obtained from endogenous beta-globin genes. Human beta-globin gene expression appeared to be restricted to cells of the erythroid lineage and was first detected between 11 and 14 days of development, in parallel with mouse beta-globin. Constructs with as little as 48 bp of 5'-flanking sequence also appeared to be expressed appropriately. The mRNA transcripts had correct 5' ends and directed human beta-globin synthesis in reticulocyte lysates. Human beta-globin protein was detectable in mature erythrocytes from progeny of one of these mice. The frequency and extent of expression was severely depressed when the procaryotic vector DNA was not removed prior to microinjection.