Early clinical experience with a candidate meningococcal B recombinant vaccine (rMenB) in healthy adults.

BACKGROUND: The development of a broadly protective vaccine against meningococcal serogroup B is a well-recognized public health need. Whole-genome sequencing was used to identify meningococcal surface proteins that are conserved across strains. These proteins were incorporated into two investigational vaccines. METHODS: Three randomized studies were performed to evaluate a three-component recombinant meningococcal serogroup B vaccine (rMenB) and rMenB plus outer membrane vesicles from the Norwegian outbreak strain 44/76 (rMenB+OMVNW). Participants were randomized to receive 3 or 4 doses of rMenB or rMenB+OMVNW or control vaccines and provided sera for exploratory immunogenicity testing against a panel of meningococcal serogroup B strains. A booster dose was administered 12 months after the initial primary series in one of the studies. The control cohort received a licensed quadrivalent meningococcal polysaccharide vaccine against serogroups A, C, W-135 and Y as well as hepatitis B vaccine as safety comparators. Solicited reactions within 7 days of any vaccination and adverse events throughout the studies were recorded. RESULTS: One hundred four participants enrolled into the clinical trials. Both rMenB and rMenB+OMVNW induced immune responses to multiple serogroup B strains in the majority of participants. Compared with rMenB, rMenB+OMVNW appeared somewhat more immunogenic and reactogenic; the study was not adequately powered for statistical assessment of these small differences. Both investigational vaccines were more reactogenic than the licensed vaccines. Few vaccinees discontinued any study due to reactogenicity to any study vaccine administered. CONCLUSION: Based on the immunogenicity and reactogenicity results in these participants, both rMenB and rMenB+OMVNW were promising candidates for further investigation.

Failure of the canine principal ascending epicardial lymphatic to regenerate after transection.

We transected the principal ascending anterior epicardial cardiac lymphatic in 10 dogs, and after varying time intervals reoperated to look for lymphatic regeneration using dye injection. Photographs and sketches were made to record the findings, and in six dogs serial histologic sections were also examined. In none of the 10 dogs was regeneration of the transected principal cardiac lymphatic detected although small lymphatic collaterals from the distal side of the lymphatic developed in 2 dogs. Further studies are merited to assess the role of lymphatic insufficiency in the development of coronary vasculopathy and chronic rejection after cardiac transplantation and other heart operations (e.g., coronary artery bypass) that may injure lymphatic drainage capacity.

Chitosans as absorption enhancers for poorly absorbable drugs 2: mechanism of absorption enhancement.

PURPOSE: It has recently been shown that the absorption enhancing and toxic effects of chitosans are dependent on their chemical composition. In this study, the mechanisms underlying these effects were investigated at the cellular level. METHODS: The effects on epithelial cells of chitosans with different chemical composition, absorption enhancing properties and toxicities were studied in Caco-2 monolayers. Chitosan C( 1:31) has a low degree of acetylation (DA) (1%) and a low m.w. (31 kD), and displays dose-dependent absorption enhancement and cytotoxicity; chitosan C(35:170) has a higher DA (35%) and a higher m.w. (170 kD), is less dose-dependent in absorption enhancement, and is not cytotoxic. A third non-toxic chitosan C(49:22) with a high DA (49%), a low m.w. (22 kD), and no influence on epithelial permeability was used as control. RESULTS: C(1:31) and C(35:170) bound tightly to the epithelium. Cellular uptake of the chitosans was not observed. Both chitosans increased apical but not basolateral cell membrane permeability and induced a redistribution of cytoskeletal F-actin and the tight junction protein ZO-1. This resulted in increased paracellular permeability of hydrophilic marker molecules of different molecular weights. Addition of negatively charged heparin inhibited the cellular and the absorption enhancing effects of the chitosans, indicating that these effects are mediated via their positive charges. The onset of the effects of C(35:170) on apical membrane permeability and tight junction structure was much faster than that of C(1:31). C(49:22) did not influence any of the properties of the Caco-2 cell monolayers studied. CONCLUSIONS: The binding and absorption enhancing effects of chitosans on epithelial cells are mediated through their positive charges. The interaction of chitosans with the cell membrane results in a structural reorganisation of tight junction-associated proteins which is followed by enhanced transport through the paracellular pathway.

Visualization of the lymphatics of the heart and the mediastinal drainage pathways in the living cynomolgous (Macaca mulatta) monkey.

Our interest in the effects of impaired cardiac lymph drainage on coronary atherosclerosis led us to study the cardiac lymphatic anatomy in the monkey, generally considered the ideal experimental animal for examining coronary artery disorders. Short-term and long-term studies to visualize the cardiac lymphatic system and its mediastinal drainage pathways in 14 living monkeys confirmed that the epicardial collecting lymphatic anatomy is comparable to that of man, dog, and pig. These lymphatics, and particular lymphatic drainage to the cardiac lymph node in the right mediastinum, are difficult to visualize, in good part, because lymph uptake of such tracers as India Ink and T1824 blue dye is extremely slow. By modifying our techniques and taking cognizance of the slow lymphatic uptake of the tracers, we have been more successful in visualizing the mediastinal cardiac lymph node. Though our studies confirm that the lymphatic drainage of the monkey heart is similar to that in other mammals, we conclude that the "monkey model" has several drawbacks to study the effects of impaired cardiac lymph flow because of the laborious requirements to visualize successfully the cardiac lymph node. Perhaps the development of new markers would make this lymphatic system more approachable for experimental investigation.

The efferent cardiac lymphatic pathways in the macaque monkey.

In ten postmortem hearts of the Macaque monkey (M. mulatta), the coronary lymphatics were visualized using an India ink suspension in 2% gelatin. The left coronary lymphatic initially passed to the dorsal surface of the aortic arch. In five hearts, this lymphatic went directly to the cardiac lymph node, whereas in the others, it first ascended to the left superior tracheobronchial node and then interconnected with the cardiac lymph node. The right coronary lymphatic usually passed in front of the ascending aorta and common arterial (brachiocephalic) trunk and entered the cardiac lymph node. In two hearts, however, the right coronary lymphatic first ascended to an anterior transverse mediastinal node and from here lymphatics joined the cardiac lymph node. Those lymphatics that passed cephalad from the cardiac lymph node to the right anterior mediastinal nodes and the right paratracheal nodes ultimately emptied into the right venous angle. Those lymphatics that passed cephalad from the cardiac lymph node to the anterior transverse mediastinal nodes ultimately emptied into the left venous angle. In five other Macaque monkeys (M. mulatta and M. fascicularis) after marker injection (T1824 blue dye and micropulverized barium sulfate) into the living heart or pericardium, lymphatic drainage beyond the base of the heart could not be demonstrated. Whereas postmortem morphologic studies suggest that the monkey coronary lymphatic system is amenable to obstruction by removal of the cardiac lymph node and interruption of its adjacent lymphatic connections, effective methods for visualizing the mediastinal lymphatic collecting system in the living monkey must be developed before experimental cardiac lymphatic ablation can be accomplished in this species.

The role of the lymphatic system in coronary atherosclerosis.

Arguments are presented to support the hypothesis that the integrity of the coronary lymphatic system is an important factor in the development of coronary atherosclerosis. It is proposed that the lymphatic drainage of the epicardial coronary arteries is genetically inadequate, and that the flow of lymph from the heart is further impaired by gravitational factors due to man's upright position. Arguments are presented to support the concept that the intramural coronary arteries are protected from atherosclerosis because of a highly effective pericoronary lymphatic and venous capillary system and that the internal thoracic (internal mammary) artery is similarly protected from atherosclerosis because of its close relationship to an extensive lymphatic chain. It is proposed that the failure of the cardiac lymphatic system in the allogenic transplanted heart is a cause of the accelerated atherosclerosis in both epicardial and intramural coronary arteries.

The lymphatic drainage of the pericardial space in the dog.

The purpose of this study was to characterize definitively the lymphatic drainage system of the pericardial space in the dog. The reports on this subject, based on dissection experiments and acute dye injections, remain controversial, and our own previous studies have been incomplete. Seventeen dogs were studied using a radiographic technique. Micropulverized barium sulfate instilled into the pericardial sac was followed with serial chest x-rays in seven dogs with intact cardiac lymphatics, in seven dogs after section of the cardiac lymphatic drainage node (the cardiac lymph node) in the right upper mediastinum, and in three dogs after resection of cardiac drainage lymphatic nodes in the left upper mediastinum. These studies revealed that the lymphatic drainage of the pericardial space is via (a) the principal coronary lymphatic which drains from the left ventricular muscle and passes to the right upper mediastinum via the cardiac lymph node, (b) the lesser coronary lymphatic which drains the right ventricular muscle and passes to the left upper mediastinum, and (c) bilateral internal mammary (parasternal) lymphatic chains. These observations are important in planning experimental approaches to the effects of impairment of lymph drainage from the pericardial space. An understanding of the lymph drainage from the pericardial space may prove significant to understanding fibrotic reactions within it and the pathologic mechanisms of such entities as constrictive pericarditis.

Latency of Plasma Membrane H-ATPase in Vesicles Isolated by Aqueous Phase Partitioning : Increased substrate Accessibility or Enzyme Activation.

The properties of the plasma membrane H(+)-ATPase and the cause of its latency have been studied using a highly purified plasma membrane fraction from oat (Avena sativa L., cv Victory) roots, prepared by aqueous two-phase partitioning. The ATPase has a maximum specific activity (at 37 degrees C) in excess of 4 micromoles inorganic phosphate per milligram protein per minute in the presence of nondenaturing surfactants. It is inhibited by more than 90% by vanadate, is specific for ATP, has a pH optimum of 6.5, and is stimulated more than 4-fold by 50 millimolar K(+) in the presence of low levels of the nondenaturing surfactants Triton X-100 and lysolecithin. This ;latent' activity is usually explained as being a result of the inability of ATP to reach the ATPase in right-side out, sealed vesicles, until they are disrupted by surfactants. Consistent with this idea, trypsin digestion significantly inhibited the ATPase only in the presence of the surfactants. Electron spin resonance spectroscopy volume measurements confirmed that surfactant-free vesicles were mostly sealed to molecules similar to ATP. However, the Triton to protein ratio required to disrupt vesicle integrity completely is 10-fold less than that needed to promote maximum ATPase activity. We propose that plasma membrane ATPase activation is due not solely to vesicle disruption and accessibility of ATP to the ATPase but to the surfactants activating the ATPase by altering the lipid environment in its vicinity or by removing an inhibitory subunit.

Comparative study of warfarin versus antiplatelet therapy in patients with a St. Jude Medical valve in the aortic position.

To determine the necessity of long-term warfarin anticoagulation after St. Jude Medical aortic valve replacement in adults, we evaluated the risks of thromboembolism, valve thrombosis, anticoagulant hemorrhage, and sudden cardiac death in two groups of patients. Group I consisted of 41 patients treated with conventional long-term warfarin therapy. Forty-two patients in Group II were treated primarily with antiplatelet therapy (aspirin, dipyridamole, or both); 17 of these patients received warfarin for a short time postoperatively and seven others received it intermittently during the study period. The groups were similar with respect to age, sex, associated cardiovascular disease, and length of follow-up (mean 29 months per patient). In the warfarin-treated group, three late sudden deaths occurred, one of which was preceded by a cerebrovascular accident, for a cardiac mortality of 2.7% per patient-year. There were eight major nonfatal complications (7.3% per patient-year), of which four were hemorrhagic and four embolic. In Group II, there was one sudden cardiac death (1.1% per patient-year) and four major complications occurred (3.2% per patient-year). Two of the complications were embolic and two were episodes of valve thrombosis, both necessitating reoperation. Although the incidence of serious morbidity in the warfarin-treated group was twice that of patients treated with antiplatelet therapy, there were no statistically significant differences in the rates of sudden death or major complications. These data suggest that antiplatelet therapy may be as effective as warfarin in preventing embolism from the St. Jude Medical valve in the aortic position. Valve thrombosis occurred in two patients, both receiving antiplatelet therapy (2.2% per patient-year). Whether this type of valve failure can be prevented by warfarin remains in question.

An eight-year experience with porcine bioprosthetic cardiac valves.

A total of 589 porcine bioprostheses were implanted in 509 patients from January, 1976, through December, 1983. Of the valves implanted, 390 were Hancock and 199 were Carpentier-Edwards. A total of 1,633 patient-years was accrued, with a mean follow-up of 38 months per patient. Two hundred eight patients had aortic valve replacement, 209 had mitral valve replacement, and 79 had multiple valve replacements, of which 46 were aortic and mitral replacements. The mortality for isolated aortic valve replacement was 5.8%; for isolated mitral replacement, 8.6%, and for all patients, 10.9%. Late mortality was 3.9% per patient-year. The actuarial survival rate at 5 years was 79% for aortic, 68% for mitral, and 76% for aortic-mitral valve replacement. There were 12 thromboembolic events (0.73% per patient-year). Two episodes occurred in patients with an aortic bioprosthesis, nine in patients with a porcine mitral valve, and one in a patient with mitral and tricuspid bioprosthetic valves. The probability of remaining free of thromboembolism at 5 years was 99% for the group having aortic valve replacement, 93% for those having mitral replacement, and 100% for the group having aortic-mitral valve replacements. Thirteen episodes of endocarditis occurred (0.8% per patient-year). Seven of the 13 patients died as a direct result of endocarditis. The probability of remaining free of prosthetic endocarditis at 5 years was 97% for the aortic valve replacement group, 95% for the mitral group, and 97% for the aortic-mitral group. There were 20 instances of xenograft failure (1.2% per patient-year). The probability of remaining free of valve failure at 5 years was 96% for the aortic valve replacement group, 93% for the mitral group, and 93% for the aortic-mitral replacement group. Primary tissue failure of a prosthesis occurred in seven patients, all with Hancock valves (0.43% per patient-year). As yet there has been no primary tissue failure of the Carpentier-Edwards prosthesis. There also appears to be a lower incidence of thromboembolism (Edwards, 0.3% per patient-year; Hancock, 0.8% per patient-year) and endocarditis (Edwards, 0.6% per patient-year; Hancock, 1.0% per patient-year). The low incidence of complications with the porcine bioprosthetic valve, especially the Carpentier-Edwards, encourages us to recommend its continued use, especially in situations in which anticoagulation is contraindicated.

Effect of suloctidil on platelet function in patients with shortened platelet survival time.

The effect of suloctidil (600 mg/day) on platelet survival time (PST) and plasma and urine betathromboglobulin (BTG) was studied in a double-blind, placebo-controlled six-week crossover trial in 13 patients with shortened PST (less than 110 hrs, exponential model). Mean PST after suloctidil (110.6 hrs) was significantly higher than in the placebo phase (94.5 hrs) (p = 0.04). Mean plasma BTG was significantly lower during the suloctidil phase (42.8 ng/ml) compared with the placebo phase (65.8 ng/ml) (p = 0.02), but there was no significant difference in urine BTG. These results suggest that suloctidil provides a platelet protective effect and therefore may be of benefit in reducing the frequency of platelet mediated thromboembolic events.

Evaluation of a commercial kit for the radioimmunoassay of fibrinopeptide A.

Measurement of fibrinopeptide A (FpA) provides a sensitive and specific marker of thrombin generation and is important in the investigation of the mechanisms involved in thrombosis and hemostasis. However, current methods available for determination of FpA by radioimmunoassay (RIA) require rigorous method development. Recently, a commercial kit (Mallinckrodt Corp: M-Kit) for the RIA of FpA has become available which contains all the necessary reagents for the assay. We evaluated this kit and compared it to an assay prepared from a commercial kit (IMCO Corp: I-Kit) which contains only the raw materials. Both assays had similar characteristics and duplicate plasma samples assayed using both methods were not significantly different. Separation of FpA from fibrinogen using bentonite slurry (M-Kit) proved superior to the ethanol precipitation method (I-Kit). The complete kit (M-Kit) will provide the routine hemostasis laboratory with an RIA for FpA which is immediately available.

Rehabilitation of blind patients with lower extremity amputations.

Twelve consecutive blind amputee patients, including 7 unilateral and 5 bilateral amputees with a median age of 64 years, were studied. All were fitted with prostheses, and gait training was accomplished on an outpatient basis. Seventy-five percent of patients were successfully ambulating 2 years or longer following the amputation; 5 regained their preoperative levels of activity; 3 lost 1 grade; 4 lost 2 or more grades. All patients claimed that the quality of life had improved and self-respect was restored with the fitting of a prosthesis.

Taussig-Bing anomaly with straddling mitral valve.

Five patients with the left-sided or intermediate type (Lev) of the Taussig-Bing anomaly were found to have an associated straddling of the mitral valve. In four patients the anomaly of the mitral valve was not recognized preoperatively, and all four died postoperatively. The persistent subpulmonic obstruction caused by the abnormal attachment of the anterior mitral leaflet is considered a significant factor in the poor operative outcome. Retrospective study of angiograms in these four patients revealed diagnostic clues of straddling mitral valve which enabled us to diagnose a fifth patient angiographically and confirm the diagnosis by cross-sectional echocardiography. A surgical approach to correct this association of abnormalities is proposed which avoids operating upon the mitral valve. Its function is thereby preserved, yet the hemodynamic problem caused by the straddling is bypassed. The fifth patient in this series was successfully treated by the proposed operative method.

A case of myocardial abscess evaluated by radionuclide techniques: case report.

A patient with infective endocarditis was evaluated by Ga-67 citrate imaging, Tc-99m pyrophosphate imaging, equilibrium gated blood pool imaging, and Tl-201 imaging of the chest. The diagnosis of ventricular abscess was first suggested by an abnormal gallium scan. At surgery, an abscess was identified in the area where the scan was abnormal, and postoperatively a repeat scan was normal.