Mutations on 170Glu, a substrate recognition residue in mouse cAMP-dependent protein kinase, generate enzymes with altered substrate affinity and biological functions

Site-directed mutations in the catalytic subunit of mouse cAMP-dependent protein kinase (PKAcat) were generated to assess the residue(s) important for the recognition of the substrate peptide and its biological functions. Since the region, 165R-166D-167L-168K-169P-170E-171 N of PKAcat has been shown to be located near the substrate analogue inhibitor peptide binding site (Knighton et al. (1991) Science 253, 414-420), we initially constructed three PKAcat mutants, D166A, K168A, and E170A, in which 166D, 168K, and 170E, respectively, were altered to alanine. When expressed in COS7 cells, D166A and K168A were insoluble, whereas E170A was soluble but had lower in-vitro kinase activity than the wild-type PKAcat. E170A and other 170E mutants, E170Q, E170V, E170R and E170D were equally soluble and displayed various catalytic activities with increased Km and decreased Vmax with regard to Kemptide substrate. Most prominently, E170R did not phosphorylate Kemptide, suggesting that 170E is important for the interaction with Kemptide. The in-vivo activities of the PKAcat mutants were examined in two independent biological assays. First, in Jurkat cells, overexpression of all the 170E mutants except E170R activated the c-fos promoter at various levels lower than the wild-type PKAcat, suggesting that these mutants retain at least partial biological activity. Second, progesterone-induced germinal vesicle break-down in Xenopus oocytes, inhibited by expression of wild-type PKAcat, was inhibited to a similar extent by all the 170E mutants except E170R. All these results support the idea that 170E is a peptide-recognition residue.

[Histological observations on the sclera in uveal effusion]

The author performed sclerectomy in six cases of uveal effusion syndrome and examined the excised sclera histologically. From the findings of the sclera during the surgery and histological findings of the excised sclera, uveal effusion syndrome was divided into three groups: 1) nanophthalmos, 2) non-nanophthalmos with hypertrophic sclera, 3) non-nanophthalmos with normal thick sclera. In all cases, glycosaminoglycans were found to be deposited around the scleral collagen fibers. In the nanophthalmic eyes (group 1) and non-nanophthalmic eyes with the hypertrophic sclera (group 2), much glycosaminoglycans were demonstrated around the collagen bundles and enlarged the collagen bundle spaces. In these groups, sclerectomy procedures were successful and, based on the successful result of the operation, the cause of uveal effusion was considered to be disturbance of outflow of intraocular fluid through the hypertrophic sclera. In non-nanophthalmic eyes with normal thick sclera (group 3), few glycosaminoglycans was demonstrated around the collagen bundles with less abnormality, and sclerectomy procedure was not effective. In this group, the occurrence of uveal effusion was another cause but abnormal sclera.

The longevity of the immune response to filamentous hemagglutinin and pertussis toxin in patients with pertussis in a semiclosed community

Titers of antibodies to the filamentous hemagglutinin (FHA) and pertussis toxin (PT) of Bordetella pertussis were studied in patients from a semiclosed community after an outbreak of the disease in 1985 and in the general population. In convalescent-phase serum obtained after B. pertussis infection in patients in the semiclosed community, high anti-FHA IgG and anti-PT IgG titers were observed; these titers tended to disappear over the next 5 years. On the other hand, among the medical staff, high anti-FHA and anti-PT IgG titers persisted during the same 5-year period. It seems likely that anti-FHA and anti-PT IgG levels reflect the frequency of exposure to the bacteria and that B. pertussis is widespread in the Japanese population. Although the anti-FHA IgG antibody response decreased in patients from the semiclosed community, the cellular immune response was maintained.

Experimental study on Reye's syndrome: inhibitory effect of interferon alfa on acetylsalicylate-induced injury to rat liver mitochondria

Viral infection and acetylsalicylate (ASA)-induced mitochondrial aberration have been reported to play important roles in the pathogenesis of Reye's syndrome. We report that increasing amounts of ASA (0 to 250 mumol/L) resulted in increases in state 4 respiration and decreases in state 3 respiration in rat liver mitochondria in vitro when using alpha-ketoglutarate and/or beta-hydroxybutyrate as respiratory substrates, but not when using succinate as substrate. Interferon alfa (IFN-alpha) (1.5 to 5 x 10(4)IU/mL, approximately 1/100 the therapeutic dosage for humans) and interleukin-1 (IL-1) (1.5 to 2 x 10(4)IU/mL, nearly equivalent to the therapeutic dosage) decreased the severity of the above effects via interaction with mitochondrial membranes. Interferon gamma (IFN-gamma) and interleukin-2 (IL-2) had no such protective effect. Electron microscopic observation indicated that IFN-alpha prevented the induction of mitochondrial swelling by ASA. These results suggest that IFN-alpha may prove to be effective for the treatment of Reye's syndrome.

Stimulatory effect of interleukin-1 beta on the interferon-gamma-dependent HLA-DR production

Expression of major histocompatibility complex (MHC) class II genes is induced by interferon-gamma (IFN-gamma) in antigen-presenting cells. When human leukaemia THP-1 and PL-21 cells were pretreated with phorbol ester, IFN-gamma-dependent induction of MHC class II gene was markedly enhanced. To elucidate the mechanism of the phenomenon, we examined the effect of cytokines which were secreted from THP-1 cells by the treatment of phorbol ester. Among those cytokines, interleukin-1 beta (IL-1 beta) had a positive effect on IFN-gamma-dependent induction of MHC class II genes. In order to rule out the possibility that different clones of THP-1 cells respond independently to IFN-gamma or phorbol ester, we showed that all independent single clones expressed MHC class II and produced IL-1 beta by IFN-gamma or phorbol ester, respectively.

Inhibition of interferon-gamma- and phorbol ester-induced HLA-DR and interleukin-1 production by the expression of a transfected poly(ADP-ribose) synthetase gene in human leukemia THP-1 cells

We have examined a correlation between an expression level of poly(ADP-ribose) synthetase gene and the stage of monocytic differentiation. We selected three human leukemia cell lines, U937, THP-1, and J111, whose differentiation stage was characterized by nitroblue tetrazolium reduction activity, non-specific esterase activity, phagocytic activity and a cell surface marker. Enzyme activity and mRNA level of the synthetase decreased in accompaniment with the progress of monocytic differentiation. When THP-1 cells were treated with either interferon-gamma or phorbol ester, mRNA level of the synthetase decreased and HLA-DR or interleukin-1 was induced, respectively. We transfected expression plasmid of the exogenous synthetase gene to examine whether the down-regulation of the synthetase is a necessary step to induce these proteins. An expression of the exogenous synthetase gene inhibited the interferon-gamma- and phorbol ester-dependent induction of HLA-DR and interleukin-1. The results suggest that down-regulation of the synthetase may be a signal mediator of immunological response such as HLA-DR or interleukin-1 production in monocytes.

[Laser photocoagulation for experimental choroidal neovascularization. 1. Mild dye laser photocoagulation]

The author treated experimentally produced choroidal neovascularization (ChNV) with mild dye laser photocoagulation (PHC). We treated these ChNVs with 590 nm wavelength, 200 microns spot size, 0.2 second duration and 50 mW of power. Eleven eyes of nine rhesus monkeys were used. Then these ChNVs were examined clinically and histopathologically at 24 hours, 2 weeks and a month after therapeutic PHC. Small ChNVs, less than 1/3 disc diameter healed successfully and histopathologically most of them were coagulated and disappeared. A few poorly developed ChNVs remained, but were well enveloped by the proliferating retinal pigment epithelial (RPE) cells. On the other hand, ChNVs of more than 1/3 disc diameter did not respond to weak PHC, grew actively over a month, and were not completely surrounded by proliferating RPE cells. These results suggest that by mild PHC, small ChNVs may be treatable, however, in large ChNVs, mild PHC may rather accelerate their activity.

Enhanced expression of poly(ADP-ribose) synthetase gene in malignant lymphoma

Over-expression of cellular protooncogenes has been proposed to function in the initiation and maintenance of malignancies. In order to distinguish malignant lymphoma from reactive proliferative diseases, we surveyed the expression levels of three protooncogenes(c-myc, c-fos and c-myb) in malignant lymphoma and reactive proliferative diseases. An increased level of c-myc or c-fos mRNA was observed in one case, respectively, out of three malignant lymphomata. The other cases exhibited no enhancement in protooncogenes. These oncogenes are critically regulated during differentiation, but the half-life of c-myc mRNA was very short, and the level of the mRNA decreased to the initial level very quickly. Thus, the high level of the expression of these oncogenes may not always be maintained in all malignant cells. We then examined the level of mRNA for poly(ADP-ribose) synthetase in those cases. An enhanced expression for the synthetase gene was observed in all five malignant lymphomata tested, but no increase in the level of the mRNA was observed in any reactive proliferative cases or normal lymph nodes. These results suggest that enhanced expression of poly(ADP-ribose) synthetase gene seems to be a common characteristic of protopathic malignant lymphoma. By using the characteristics of malignant lymphoma, the level of mRNA for the synthetase may be applicable for differential diagnosis of malignant lymphoma from several pathologically indistinguishable diseases.

Fluctuation of gene expression for poly(ADP-ribose) synthetase during hemin-induced erythroid differentiation of human leukemia K562 cells and its reversion process

We have studied the regulation of gene expression for poly(ADP-ribose) synthetase during erythroid differentiation and its reversion process. When human leukemia K562 cells were incubated in the presence of 80 microM hemin, benzidine-positive cells appeared at day 2 and 90% of the cells became positive at day 6. However, RNA blot analysis reveals that mRNA for gamma-globin was already abundant in untreated K562 cells and the level of the message was slightly increased by hemin-treatment. Spectroscopic analysis and polyacrylamide gel electrophoresis of the induced cell extracts indicate that hemoglobin molecules were not detected in untreated cells, and increased successively up to day 6. The hemin-induced cells were thoroughly washed, and then recultured in the absence of hemin. The benzidine-positive cells mostly disappeared 3 days after the elimination of the inducer. During the hemin-induced erythroid differentiation, the activity and mRNA for poly(ADP-ribose) synthetase decreased to 50% and 20% of the initial level at day 3 and a low level of the gene expression was maintained afterwards, whereas the activity and mRNA returned to the initial value 1 day after hemin elimination. The results indicate that the hemin-induced erythroid differentiation of K562 cells is a reversible process and depression of the synthetase may be involved in the progress of differentiation.

Immune responses to Bordetella pertussis infection and vaccination

To assess antibody and cellular immune responses, 156 healthy children were immunized at approximately 18 months of age with acellular diphtheria-tetanus-pertussis vaccine. Changes in antibody responses to filamentous hemagglutinin (FHA) and to pertussis toxin (PT) were similar in pattern, and antibody titers reached values equal to those from patients with convalescent-stage pertussis. The FHA-induced DNA synthesis in peripheral blood mononuclear cells was maximum at 4 weeks after the primary series, and these levels were equal to those of patients with pertussis. High amounts of PT-induced DNA synthesis were observed in both immunized and nonimmunized children; thus, PT seemed to act mainly as a nonspecific mitogen. Almost the same responses to several mitogens that activate different subsets of lymphocytes were observed in young infants compared with older children. Furthermore, young infants who had Bordetella pertussis infection responded by FHA stimulation almost as well as older children.

Changes in Cu,Zn-superoxide dismutase gene during induced erythroid and myeloid differentiation

We investigated the alteration of Cu,Zn-superoxide dismutase during erythroid and myeloid differentiation in order to elucidate its physiological significance in different types of cells. We measured enzyme activity and mRNA levels of superoxide dismutase in the process of differentiation to erythroid cells or myeloid cells. When human leukemia K562 cells are incubated in the presence of 80 microM hemin, benzidine-positive cells appear on day 1 and 80% of the cells become positive on day 5. During hemin-induced erythroid differentiation, Cu,Zn-superoxide dismutase activity increases 3.5-fold of the initial value and mRNA for Cu,Zn-superoxide dismutase increases prior to the activity to the same extent. On the other hand, when human promyelocytic leukemia HL-60 cells are incubated in the presence of 1.3% dimethyl sulfoxide, nitroblue tetrazolium-positive cells reach approximately 90% on day 5. During dimethyl sulfoxide-induced myeloid differentiation, the activity of Cu,Zn-superoxide dismutase decreases below 15% of the initial value on day 5 and mRNA for Cu,Zn-superoxide dismutase decreases as well. The results indicate that the synthesis of superoxide dismutase is linked with either the erythroid or myeloid differentiation program.

[Treatment and prognosis of retinoblastoma from 1975 to 1987]

Among 21 cases of retinoblastoma (28 eyes) treated during the past 14 years in our clinic, 14 cases were unilateral, and 7 were bilateral. The average ages at the first visit were 27 months in unilateral cases and 7.2 months in bilateral cases. In all unilateral cases, in all of which the tumors were large (over group III according to Reese's classification), we removed the affected eye, and all patients survived without any evidence of metastasis or recurrence during a 5-year follow-up period. In bilateral cases, we removed the advanced eyes in which the tumors were large (over group III according to Reese's classification) in all cases, and the contralateral eyes underwent conservative treatment by radiotherapy, photocoagulation or chemotherapy. When tumors in contralateral eyes were small (Group I or II in Reese's classification), tumors of the retina subsided and all patients survived without recurrence or metastasis. However, when the tumors were large (group V), tumors of retina did not subside and survival was very poor. Our results show that the prognosis for survival in bilateral cases depends mainly upon the size of the tumor in the remaining eye.

[Clinical efficacy and safety of norfloxacin tablets in pediatrics]

We have evaluated norfloxacin (NFLX) tablets for therapeutic effectiveness and safety in children. The results are summarized as follows. 1. A clinical study was performed on 14 children with infections, including 12 with urinary tract infections and 2 with acute bronchitis. Doses ranging from 1.7 to 5.4 mg/kg body weight were given b.i.d. or t.i.d.. Lengths of treatment ranged from 3 to 15 days. The therapeutic responses were considered "excellent" in 8 and "good" in 5, with an efficacy rate of 93%. 2. Side effects were observed in 2 cases, one with light-headed feeling and one with vomiting. In clinical laboratory tests, eosinophilia was found in 2 cases and GOT was slightly elevated in 1 case. It has been concluded that NFLX is a usable drug for the treatment of bacterial infections in children.

Congenital alveolar rhabdomyosarcoma presenting as a blueberry muffin baby

Congenital alveolar rhabdomyosarcoma in a newborn was reported. She had multiple subcutaneous tumors and looked like a blueberry muffin baby. From the clinical signs and the histological pictures, a diagnosis of neuroblastoma was considered. Laboratory data showed no abnormalities. Electron microscopic examination revealed myofilament and incipient stria formation. On the basis of these data, a final diagnosis of congenital alveolar rhabdomyosarcoma associated with multiple skin metastases was made.

[Therapeutic effects of cefodizime in the treatment of various infectious diseases in children]

Therapeutic effects of cefodizime (CDZM, THR-221), a new cephalosporin having a methoxyimino group, were examined in various infectious diseases in children. Clinical efficacy rates were 100% (3/3) in pneumonia, 100% (5/5) in acute bronchitis, 75% (3/4) in upper respiratory infections and 100% (1/1) in each of a croup and a mixed infection with Streptococcus pyogenes and staphylococcal impetigo. Hence, the overall efficacy rate was 92.9% (13/14). Adverse effects were observed in 2 cases, i.e. exanthema provably due to drug allergy in 1 case and a slightly elevated GPT in another. Changes in serum concentrations and urinary excretion of CDZM were examined in a child with no infection. T 1/2 values obtained were 124.5 minutes (bioassay) and 143.4 minutes (high performance liquid chromatography (HPLC]. Eight hour recovery rates in urine were 62.9% (bioassay) and 65.4% (HPLC). CDZM was considered to be a safe and useful drug in treating various infectious diseases in children.

[Allergological study of breast feeding, ovalbumin and specific IgG, IgM and IgA antibodies to ovalbumin in human milk]

Ovalbumin (OA) and specific antibodies to OA were evaluated by ELISA in 92 colostrum, 366 mature milk and 12 cord blood samples. Anti-OA IgG antibody titers in colostrum were lower than those in cord blood and were not detectable in several samples. Anti-OA IgM antibody titers in colostrum were comparatively high and decreased on the days following postpartum. Anti-OA IgA antibody titers were the highest in the colostrum and decreased on the following days, but remained constant in mature milk. On the other hand, OA was detected in 27.2% of colostrum and 17.2% of mature milk samples, in concentrations from 0.5-59.0 ng/ml. In mature milk, the positive rates of OA were significantly elevated by egg ingestion by the mothers. OA in mature milk from allergic mothers tended to be more readily detectable than that from non-allergic mothers. These results suggest that avoidance of the specific food antigens by mothers is important for therapy and prevention on allergic disease in their breast-fed infants.

[Clinical efficacy of sulbactam/ampicillin in the field of pediatrics]

Sulbactam (SBT) is a new derivative of the basic penicillin nucleus. It effectively and irreversibly inhibits several important bacterial beta-lactamases and displays synergistic effects against the resistant organisms when co-administered with ampicillin (ABPC). SBT/ABPC, which is a fixed combination of SBT and ABPC in a 1:2 ratio, was studied for clinical efficacy in the field of pediatrics. Patients treated were infants and children ranging from 12 days to 13 years and 2 months old suffering from acute tonsillitis in 2 cases, acute bronchitis in 2 cases, septicemia in 2 cases, acute enteritis, acute pyelonephritis and osteomyelitis in 1 case each, a total of 9 cases. SBT/ABPC was administered 100-300 mg/kg in daily doses and durations of treatment ranged from 4 to 17 days. Clinical results were "excellent" in 6 and "good" in 2: the efficacy rate was 88.9% or 8 cases out of 9. Neither clinical side effects nor abnormal laboratory findings obviously attributable to SBT/ABPC were observed in any cases.

[Clinical efficacy of clarithromycin in the field of pediatrics]

A new macrolide antibiotic, clarithromycin (TE-031, A-56268), was studied for its clinical efficacy in the field of pediatrics. Patients treated were infants and children ranging from 2 months to 11 years old suffering from acute bronchitis in 5 cases, acute tonsillitis in 2 cases, Mycoplasma pneumonia in 2 cases, pertussis in 6 cases, scarlatina in 1 case and acute enteritis in 2 cases, a total of 18 cases. TE-031 was administered 19.7-43.5 mg/kg in daily doses and lengths of treatment ranged from 4 to 19 days. As regards to its clinical efficacy, good or excellent results were obtained in all cases: excellent in 11 cases and good in 7 cases. No clinical side effects nor abnormal laboratory test values obviously attributable to TE-031 were observed.

[Pharmacokinetics and clinical effects of sultamicillin fine granules in pediatrics]

We have evaluated sultamicillin (SBTPC) fine granules for pharmacokinetics and therapeutic effectiveness in children. The results are summarized as follows. 1. Pharmacokinetic parameters after the oral administration of single dose of 5.0 mg per kg body weight in 1 child were as follows: The peak serum concentrations of ampicillin (ABPC) and sulbactam (SBT) were 1.92 micrograms/ml at 1 hour and 1.85 micrograms/ml at 1 hour, respectively. The half-lives in serum and urinary excretion rate for ABPC and SBT were similar. 2. A clinical study was performed on 15 children with infections, including 4 with tonsillitis, 5 with pharyngitis, 2 each with bronchitis, cystitis, and urinary tract infections. Doses ranging from 6.7 to 18.2 mg/kg body weight were given tid. or qid. Lengths of treatment ranged from 5 to 10 days. The therapeutic responses were considered "excellent" in 6 and "good" in 9, with an effectiveness rate of 100%. 3. As to side effects of the drug, diarrhea was observed in 1 patient. It was concluded that SBTPC was a promising drug for the treatment of bacterial infections in children.

A new system for real-time synthetic aperture ultrasonic imaging

The authors devised a way to generate in real time a cross-sectional image of an object with uniformly high resolution based on the synthetic aperture focusing technique (SAFT). A computer simulation was conducted to study the effects of essential parameters on the resulting images. An imaging system was built that produces a cross-sectional image composed of an assembly of line images of depth direction, i.e. processed A-scan images, and displays a scroll picture on a CRT (cathode ray tube) with no interruption regardless of the object size. It takes only 3 ms from the start of transmission of the ultrasonic wave to the completion of a line image reconstruction, and the framed image on a CRT is updated at the TV rate of 1/30 s. Imaging experiments were conducted using the system, and its expected performance was demonstrated.