Immunological studies of the disulfide bridge region of Pseudomonas aeruginosa PAK and PAO pilins, using anti-PAK pilus and antipeptide antibodies

Pseudomonas aeruginosa is an opportunistic pathogen that attaches to host cells via their pili. The pilus of P. aeruginosa PAK consists of a polymer of a single subunit, pilin, which is a 144-residue polypeptide. The C-terminal end of this protein is semiconserved in a number of strains and contains a disulfide bridge. We have synthesized the C-terminal peptide PAK (128-144)-OH in both its reduced and oxidized forms and the analog PAK(A-129) (128-144)-OH, in which cysteine-129 was substituted by alanine. These three peptides were used to immunize rabbits and prepare antipeptide antisera. It was found that antipeptide antisera to reduced peptide (17-R) and to oxidized peptide (17-O) bound to native PAK pili and cross-reacted with strain PAO pili in direct enzyme-linked immunosorbent assay (ELISA) and immunoblot experiments. However, the antiserum to the peptide immunogen PAK(A-129)(128-144)-OH, which does not have the ability to form the disulfide bridge, did not bind to either PAK or PAO pili. Competitive ELISA experiments with reduced and oxidized peptides of Ac-PAK(128-144)-OH showed that there was no difference in binding between the two peptides for 17-R or 17-O immunoglobulin G. When immunoglobulin G from native PAK antipilus antiserum was used in competitive or direct ELISA experiments, there was also no preference in binding to reduced or oxidized Ac-PAK(128-144)-OH or to PAK(A-129)(128-144)-OH. This result showed that the disulfide bridge in Pseudomonas pili is not critical to the immunogenicity of this region. However, the disulfide bridge is important in the immunogenicity of the C-terminal peptide when preparing antipeptide antisera that are cross-reactive with pili from different strains, since only the disulfide bridge peptide antisera cross-reacted well with the PAO pili as shown by competitive ELISA, suggesting that this region could be an important candidate for development of a synthetic vaccine.

The capacity of normal and talpid3 mutant fowl myogenic cells to migrate in quail limb buds

Talpid3 is a recessive lethal mutant of the fowl. It has been shown previously that, in vitro, talpid3 limb mesenchyme cells are more adhesive and less mobile than normal cells. It is therefore of interest to investigate the effect of the gene on cell movement in vivo, in the limb bud itself, in cells in which it is known to occur in normal embryos. Myogenic cells, which normally migrate into the limb bud from the somites, continue to move distalwards when grafted into the limb bud at a later stage. Blocks of normal or talpid3 limb mesenchyme containing myogenic cells were transplanted into quail limb buds in ovo. Since quail cells are histologically distinguishable from chick cells the progress of myogenic cell movement 5 days after transplantation could be observed. In 10 out of 14 cases normal myogenic cells migrated extensively in a proximo-distal direction within the limb bud of the quail host. In contrast, only 2 out of 11 talpid3 transplants showed a moderate degree of distalwards movement.

Influence of diandric and digynic triploid genotypes on early mouse embryogenesis

Standard micromanipulatory techniques were used to produce tripronucleate diandric and digynic triploid mouse conceptuses. When these were transferred to suitable recipients, most implanted. A wide range of embryonic stages from the primitive streak to the 15- to 25-somite stage were isolated in both triploid series in otherwise identical recipients. In the diandric triploid series, all of the embryos recovered appeared to be morphologically normal, but considerably smaller than fertilized embryos analysed at similar stages of development. This contrasts with the digynic triploid conceptuses which, though also ranging from the primitive-streak stage to about the 10- to 15-somite stage at the time of their isolation, generally showed poorer embryonic development than the diandric triploids, and were invariably morphologically abnormal. Unlike the situation observed in man, where the placentas of diandric triploid conceptuses commonly display widespread trophoblastic hyperplasia and form the characteristic ‘partial’ or ‘incomplete’ type of hydatidiform moles, the extraembryonic membranes of the diandric triploid mouse conceptuses (as well as the digynic triploids) did not appear to be grossly abnormal).

Post-implantation development and cytogenetic analysis of diandric heterozygous diploid mouse embryos

Diandric heterozygous diploid mouse embryos were produced by standard micromanipulatory techniques using eggs from female mice with a normal chromosome constitution and fertilised by homozygous Rb(1.3)1Bnr males containing a pair of large metacentric marker chromosomes in their karyotype. The constructed diandric eggs were transferred to the oviducts of pseudopregnant recipients and subsequently autopsied midday on the eighth day of gestation. From a total of 85 eggs transferred to females that subsequently became pregnant, 30 implanted. Eighteen implantation sites were found to contain resorptions, and 12 egg cylinder stage embryos were recovered. These were cytogenetically examined. In two cases, no mitoses were observed, and in a third embryo of normal size, only a single paternally-derived marker chromosome was present in its mitoses, indicating that this embryo had a normal chromosome constitution. This presumably resulted from a technical error during the micromanipulatory procedure. The remaining nine morphologically small but normal embryos were diploid, and each had two paternally-derived marker chromosomes, thus establishing their ploidy and confirming their diandric origin. G-banding analysis revealed that all of these embryos had an XY sex chromosome constitution. Since the expected XX:XY:YY ratio of 1:2:1 was not observed, it is clear that the XX class embryos were lost at some stage during the pre- or early post-implantation period, though whether they are represented by the resorption sites is not yet established. The YY class would not be expected to be recovered in any case, as these embryos are believed to be lost during early cleavage. The cytogenetic findings reported here are therefore similar to the results of the chromosomal analyses of the human complete hydatidiform moles of dispermic origin, all of which apparently have an XY karyotype. It is unclear why, both in the human and in the mouse, the XX diandric heterozygous diploid group should develop poorly compared to similar embryos with an XY karyotype.

The sex-chromosome constitution and early postimplantation development of diandric triploid mouse embryos

Diandric triploid mouse embryos were produced by standard micromanipulatory techniques, using eggs isolated from female mice with a normal chromosome constitution that had been mated to homozygous Rb(1.3)1Bnr males (which carry a large metacentric "marker" chromosome, viz., a Robertsonian translocation involving chromosomes 1 and 3). The tripronucleate embryos were transferred to the oviducts of pseudopregnant mice, which were subsequently autopsied at about midday on the 10th day of gestation. Although a relatively small number of the isolated conceptuses consisted of morphologically abnormal egg-cylinder-like structures or empty gestational sacs, most were at clearly distinguishable embryonic stages, from the primitive streak stage to embryos with about 20 pairs of somites present. These embryos all appeared to be morphologically normal but were substantially smaller than normal (diploid) fertilized embryos analyzed at similar stages of development. A total of 63 diandric triploid conceptuses were recovered and analyzed cytogenetically. They were G-banded to determine their sex-chromosome constitution and confirm their diandric triploid status. No obvious difference was observed in the developmental potential of the 58,XXX class of diandric triploids, compared to that of the 58,XXY class. The ratio of 58,XXX to 58,XXY embryos was close to the expected ratio of 1:2, assuming that unfertilized eggs have an equal chance of becoming fertilized by an X- or a Y-bearing spermatozoon and that the additional (i.e., "donor") male pronucleus also has an equal chance of having either an X or a Y sex chromosome present. However, the development of the 58,XYY class appeared to be restricted, even at the stage of gestation analyzed, in that no embryos with this genetic constitution were observed that had progressed beyond the early somite stage. The present findings are discussed in relation to the cytogenetic findings in human triploid conceptuses, the majority of which are spontaneously aborted during the first half of pregnancy. In man, the 69,XYY class (equivalent to the 58,XYY class in our study) is only rarely encountered, and it has been assumed that these triploid embryos are probably lost at a very early stage of gestation.

Treatment of fungal infections with semisynthetic derivatives of amphotericin B alpha

AME appeared to be as effective as AmB in the treatment of mycoses in humans. AME was much less nephrotoxic than AmB, and was better tolerated in terms of rapid onset and reversible adverse reactions. AME may be more ototoxic than AmB. AME, even as AmB and OAME, may cause neurotoxicity and leukoencephalopathy, particularly when high doses are given for long periods.

Role of pili in adhesion of Pseudomonas aeruginosa to human respiratory epithelial cells

The ability of pili from Pseudomonas aeruginosa K (PAK) to act as an adhesin to human respiratory epithelial cells was examined using an in vitro adhesion assay. Equilibrium analysis of PAK binding to human buccal epithelial cells (BECs) and tracheal epithelial cells (TECs) by means of a Langmuir adsorption isotherm revealed that the maximum numbers of binding sites per epithelial cell (N) were 255 for BECs and 236 for TECs, with apparent association constants (Ka) of 2.8 x 10(-9) and 5.8 x 10(-9) ml/CFU, respectively. Trypsinization of the BECs before the binding assay increased N to 605 and decreased the Ka to 1.7 x 10(-9) ml/CFU. Addition of homologous pili to the binding assay with BECs or TECs or the addition of anti-pilus Fab fragments inhibited PAK adherence. Binding of purified pili to BECs was shown to reach saturation. Purified pili and PAK competed for the same receptor on the BEC surface. Further, by using peptide fragments of PAK pilin (derived from the native pili or produced synthetically) in the binding assay for PAK to BECs, we have presumptively identified the pilus binding domain in the C-terminal region of the pilin and shown that the C-terminal disulfide bridge is important in maintaining the functionality of the binding domain.

Validity of self-report in alcoholism research: results of a Veterans Administration Cooperative Study

The validity of self-report in alcoholism treatment research is controversial. Our recently completed Veterans Administration Cooperative Study evaluating the efficacy of disulfiram treatment for alcoholism provided an opportunity to assess the validity of self-report. To assess treatment response, patients and household contacts were interviewed at seven scheduled points during the 1 year of follow-up. Blood specimens also were obtained from the patients at these times and were analyzed for ethanol. Eighty-eight percent of the patient and/or collateral interviews were obtained at 6 months and 90% at 1 year. The mean number of blood and urine specimens collected per patient was 4.3 and 14.4, respectively. Outcome criteria included continuous abstinence during the year and total number of drinking days. Continuous abstinence: If we had had only the patients' self reports, we would have significantly underestimated the percentage of men who drank. By self-report 58.7% (355/605) relapsed whereas the combination of self report, collaterals' reports, and laboratory tests indicated that 72.4% (438/605) drank (p less than 0.001). Using Bayes' theorem, the conditional probability that a patient is continuously abstinent for 1 year when he so claims is 65%. Total drinking days: Of the 213 patient-collateral pairs each of whom provided all seven scheduled interviews, 46.9% (100/213) agreed on the total number of drinking days during the year.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential photoabsorption using argon laser radiation on atherosclerotic plaque in non-hemolyzed and hemolyzed blood

Since argon laser radiation (488 to 514 nm) can vaporize human atherosclerotic plaque, we determined whether different blood media--hemolyzed versus non-hemolyzed blood--can alter photoabsorption of atherosclerotic plaque. Forty cadaveric aortic fibrous plaque samples were fitted onto small vials containing 0.02 ml of either non-hemolyzed blood or hemolyzed blood over the surface of the plaque. The distal end of a 400-mu core diameter quartz fiber was directed onto the surface of the plaque and the proximal end of the fiber was connected to an argon laser. The vaporized area and depth of plaque penetration were measured and the estimated volume of crater formation was derived. Following 2.5, 5, 10 and 20 J of laser energies, vaporized volumes were 0.12, 0.72, 0.97 and 4.09 mm3, respectively, for hemolyzed blood and were 0 (p less than 0.01), 0 (p less than 0.01), 0.92 (NS) and 4.39 mm3 (NS), respectively, for non-hemolyzed blood. Laser radiation destroys red blood cells; the higher the energies, the greater the hemolysis. Thus, different blood media such as hemolyzed and non-hemolyzed blood can alter photoabsorption of atherosclerotic plaque. Low level argon laser absorption upon plaque can occur under hemolyzed blood but not under non-hemolyzed blood. Since higher levels of argon laser energies cause greater lysis of red blood cells, comparable degrees of plaque ablation are observed under either blood medium.

Psychiatric complications of disulfiram treatment

The authors studied psychiatric complications of disulfiram use in 605 alcoholic patients. The subjects were assigned to one of three treatment groups: a 250-mg disulfiram group (N = 202), a 1-mg disulfiram group (N = 204) to control for the fear of the alcohol-disulfiram reaction, and a no-disulfiram group (N = 199) to control for the effect of psychotherapy. No significant differences in the incidence of psychiatric complications were found among the three groups. The authors conclude that if psychiatric complications follow disulfiram use, the incidence must be very low with the doses of disulfiram used presently and in the absence of predisposing factors.

Recipient growth and nutritional status following transplantation of segmental small-bowel allografts

Concerning small-bowel transplantation in children, the question arises whether a segmental small-bowel graft from an adult donor would permit normal growth of the young recipient. Orthotopic small-bowel transplantation was performed in 4- to 6-week-old Lewis rats weighing 100-135 g. The entire small bowel of the recipient was replaced with an intestinal allograft consisting of the entire small bowel (N = 6), the jejunum (N = 6), or the ileum (N = 6) from adult Brown Norway rats. Immunosuppression with cyclosporine (15 mg/kg im) on alternate days for 4 weeks achieved graft acceptance of indefinite duration. Six and twelve months after transplantation, all recipients demonstrated normal global nutritional parameters (hematocrit, serum albumin) and gained weight at a rate comparable to that for age-matched controls. Nutritional deficiencies did not become apparent clinically. By 10 to 12 months, the levels of fat-soluble vitamins (A and E) were reduced significantly in recipients of segmental grafts. Vitamin B12 levels were also reduced but not significantly. Fecal fat was significantly elevated in all rats with grafts (3.2 +/- 1.0 to 4.8 +/- 0.9 g fat/100 g stool; controls, 1.8 +/- 0.4), but the increase was most pronounced in those with jejunal grafts (4.7 +/- 0.9). This was paralleled by a reduction in serum triglyceride levels in all transplanted rats, a reduction which reverted to normal by 10 to 12 months for rats with entire small-bowel grafts but not for those with segmental grafts. Graft biopsy demonstrated normal intestinal architecture with villus hyperplasia of segmental grafts.(ABSTRACT TRUNCATED AT 250 WORDS)

Synthetic peptides as substrates for processing enzymes in the bovine pituitary

Synthetic peptides, based on sequences of proopiomelanocortin (POMC) cleaved in both the bovine anterior and intermediate pituitaries (-Phe-Pro-Leu-Gly-Phe-Lys-Arg-Glu-Leu-Thr-Gly-) and only in the intermediate lobe (-Gly-Lys-Pro-Val-Gly-Lys-Lys-Arg-Arg-Pro-Val-), were used as substrates for the enzymes that process POMC to active hormones in the anterior and intermediate lobes of the pituitary. Cleavage of these peptides at the dibasic pair of residues, the expected cleavage site, was observed with a lysate from bovine pituitary secretory granules. Cleavage occurred optimally at a pH between 4 and 5 and was inhibited with sulfhydryl reagents, pepstatin, and leupeptin. Little specificity for the nature of the basic residues at the cleavage site was observed. An additional cleavage, following glutamic acid residues, was also seen.

Disulfiram treatment of alcoholism. A Veterans Administration cooperative study

We conducted a controlled, blinded, multicenter study of disulfiram treatment of alcoholism in 605 men randomly assigned to 250 mg of disulfiram (202 men); 1 mg of disulfiram (204 men), a control for the threat of the disulfiram-ethanol reaction; or no disulfiram (199 men), a control for the counseling that all received. Bimonthly treatment assessments were done for one year. Relative/friend interviews and blood and urine ethanol analyses were used to corroborate patients' reports. There were no significant differences among the groups in total abstinence, time to first drink, employment, or social stability. Among the patients who drank and had a complete set of assessment interviews, those in the 250-mg disulfiram group reported significantly fewer drinking days (49.0 +/- 8.4) than those in the 1-mg (75.4 +/- 11.9) or the no-disulfiram (86.5 +/- 13.6) groups. There was a significant relationship between adherence to drug regimen and complete abstinence in all groups. We conclude that disulfiram may help reduce drinking frequency after relapse, but does not enhance counseling in aiding alcoholic patients to sustain continuous abstinence or delay the resumption of drinking.

Correlation of coronary angioscopic to angiographic findings in coronary artery disease

An Olympus ultrathin fiberscope, 1.8 mm outer diameter, was inserted intraluminally into 11 stenoses of the left anterior descending and circumflex coronary arteries in 8 patients at coronary bypass surgery. Intraluminal views were obtained by coupling the angioscope to a color video camera and videotape recorder, and compared with preoperative coronary angiographic findings in right and left anterior oblique views. Atherosclerotic plaque was observed as yellow-white mass attached onto the luminal lining, which may be large enough to virtually obliterate the vascular lumen. Angioscopy provided a topographic view and cross-sectional picture of stenosis not observed by angiography. Single-plane angioscopic cross-sectional stenotic lumens correlated well (r = 0.90, p less than 0.001) with calculated angiographic luminal narrowings. However, with subtotal obstruction, lesion length must be assessed angiographically. Coronary angioscopy can be a useful adjunct to angiography by providing the added dimension of the true cross-sectional view of obstruction.

High average power active-mirror amplifier

We report operation of the first high average power Nd:glass active-mirror amplifier, a scalable laser device that may be used to configure solid-state laser systems with high average power output into the kilowatt regime. An extractable average power of over 120 W was achieved at the device laser material fracture limit and at a repetition rate of 5 Hz.

Graft-versus-host disease induced by small bowel allografts. Clinical course and pathology

The histopathological changes and the course of graft-versus-host (GVH) disease were studied in the rat model of small-bowel transplantation using the Lewis----LBN-F1 strain combination. Allograft-induced GVH disease led to the recipients' death from enteritis, dermatitis and emaciation after 14.4 +/- 2.9 days (heterotopic grafts) and 14.0 +/- 0.7 days (orthotopic grafts). Histologic evidence of dermatitis (epidermal hyperkeratosis and cutaneous infiltration by mononuclear and polymorphonuclear cells) and enteritis (villous blunting and sloughing, inflammatory infiltrate of the recipient's own intestine) appeared on the 9th to 13th postoperative days, and these changes became fulminant within 2-3 days. The lymphatic tissues of the Lewis grafts and the LBN-F1 host underwent a course of progressive lymphoid depletion and loss of follicular architecture beginning on the 5th postoperative day. Throughout the postoperative course, the small-bowel graft remained intact. The relative spleen weight progressively increased until shortly before death, when a marked reduction was observed. The clinical triad of diarrhea, diffuse dermatitis, and hypertrophy of the lymphoid organs followed by their atrophy suggests a diagnosis of GVH disease rather than rejection of the small-bowel allograft. The diagnosis can be confirmed by biopsy of a recipient lymph node or the intestinal allograft (cave perforation) if it is accessible.

Portal versus caval venous drainage of small bowel allografts: technical and metabolic consequences

The potential metabolic and technical consequences of systemic (portacaval anastomosis [PC-A]) as opposed to portal venous drainage (portaportal anastomosis [PP-A]) of orthotopic small bowel isografts was evaluated in a rat model. Rats with portacaval (PC) shunts were studied for comparison. During the study period of 6 months, rats with small bowel grafts (PP-A or PC-A) gained weight at rates equal to that of normal age-matched rats (+40% of the preoperative weight) whereas rats with PC shunts lost 20% of their weight. At autopsy 6 months after operation, rats with PC shunts had significant liver atrophy (2.0% of total body weight) in comparison with rats with orthotopic isografts. Moderate liver atrophy was detected in rats with grafts and PC-A in comparison with those with PP-A (2.6% versus 2.8% of total body weight, statistically not significant). Serum ammonia levels were significantly elevated for PC shunts (560 +/- 148 micrograms/dl) and PC-A (140 +/- 22 micrograms/dl) when compared with PP-A (83 +/- 10 micrograms/dl). In terms of technical difficulties, both PC-A and PP-A could be achieved with the same success rate. Systemic venous drainage for small bowel grafts is followed by metabolic alterations that are similar, although much less pronounced, to those seen after a PC shunt. Thus our findings do not offer compelling reasons to prefer PP-A over PC-A. However, with longer follow-up and the use of hepatotoxic immunosuppressive drugs, these minimal alterations may progress and induce metabolic sequelae of clinical significance. Under these circumstances it would be advisable to use the physiologic portal drainage rather than systemic venous drainage in small bowel transplantation.

Structure and function of orthotopic small bowel allografts in rats treated with cyclosporine

Previous studies of small bowel transplantation using a variety of animal models and immunosuppressive regimens have failed to demonstrate consistently prolonged survival of bowel allografts capable of maintaining a normal nutritional state. In the present study, total orthotopic small bowel transplantation was performed in inbred rat strains to determine the structure and function of intestinal allografts using cyclosporine for immunosuppression. Without cyclosporine, Lewis-Brown Norway and Brown Norway allografts were quickly rejected by Lewis recipients, resulting in host death. A 15 mg/kg dose of cyclosporine given intramuscularly immediately after operation and for 6 successive days thereafter achieved prolonged but not uniformly indefinite animal and graft survival with clinical courses and pathologic findings consistent with chronic rejection. With continuation of cyclosporine every other day until day 28, all Lewis recipients of Brown Norway allografts were alive and well 8 months after transplantation. Weight gain, maltose absorption, and multiple nutritional indices in these animals were not significantly different from those of either age-matched normal Lewis rats or recipients of Lewis isografts. Full-thickness biopsy specimens of these allografts showed no evidence of graft rejection. These results demonstrate that indefinite survival of intestinal allografts with preservation of their structure and function sufficient to allow normal growth and weight gain can be achieved with cyclosporine therapy. This success in the rat model of orthotopic small bowel transplantation suggests that clinical small-bowel transplantation may become possible using cyclosporine.