Rational design of a stable, freeze-dried virus-like particle-based vaccine formulation.

Virus-like particles (VLPs) have been extensively explored as vaccine candidates since the mid-1980s. Numerous VLPs have been designed as vaccines for prevention of virus-induced infectious diseases and for the therapeutical treatment of chronic diseases and drug addiction. Recently, a vaccine against nicotine addiction, which is based on VLPs of the RNA phage Qb to which nicotine haptens are covalently coupled via succinimate linkers (NicQb), has attracted a great deal of interest. Phase II clinical trials with this vaccine have shown that it is efficacious for smoking cessation in humans when antinicotine antibody levels are sufficiently high. For commercialization, the development of stable formulations enabling storage for prolonged periods is required. Hereby, lyophilization, a well-established method leading to stable and dry formulations, is often applied. In this study, we investigated the influence of different pH values and various excipients such as surfactants, polyols, sugars, and salts on the stability of NicQb in liquid formulations, during freeze thawing, freeze drying, and finally upon storage of the dried product. Lyophilized NicQb formulations were developed which were stable over 6 months at ambient temperature with fully retained biological activity. Hereby, it was found that a combination of the surfactant polysorbate 20 and the disaccharide trehalose was capable to prevent NicQb aggregation and to preserve its integrity (nicotine binding and integrity of VLP shell). Furthermore, asymmetrical flow field-flow fractionation (AF4), a new, promising analytical tool, was established for the investigation of VLP stability.

Efficacy of femoral intra-arterial administration of teicoplanin in gram-positive diabetic foot infections.

In this study the efficacy and safety femoral intra-arterial administration of teicoplanin in the treatment of diabetic foot infections caused by gram-positive bacteria were evaluated. Twenty-five hospitalized diabetic patients with foot ulcers or with foot ulcers and metatarsophalangeal osteomyelitis were included in the study. In the ulcers Staphylococcus aureus was present alone in 16 patients and was associated with Pseudomonas aeruginosa in 2 patients, with Candida albicans in 2, and with coagulase-negative Staphylococcus in 1 patient. In 4 patients other gram-positive bacteria were isolated. All isolated strains were resistant to various antibiotics tested. Teicoplanin, 200 mg, was administered once a day by femoral intra-arterial injection for an average period of 14.72 +/- 7.16 days (range ten to thirty-six days). Six patients were treated with an additional antibiotic intramuscularly or intravenously because of a mixed infection. At the end of the therapy microbiological assessment confirmed that gram-positive infection was eliminated in all patients. Clinical outcome demonstrated that healing occurred in 18 patients (72%) and improvement in 7 patients (28%). No adverse drug reactions were observed during the treatment. The results demonstrate that femoral intra-arterial administration of teicoplanin was highly effective in skin- and bone-infected lesions in the diabetic foot. This method may represent a further advantage in management of this severe diabetic complication.

[Flowmetric, thermometric and rheologic studies in obliterating arterial diseases of the lower extremities treated with buflomedil]. / Studio flussimetrico, termometrico e reologico nelle arteriopatie obliteranti degli arti inferiori trattate con buflomedil.

Ten subjects with peripheral arterial occlusive disease were treated with buflomedil, analysing the effect of every single intravenous administration of the drug, and the effect of the administration repeated for a period of 5 days. This controlled study was aimed at evaluating the state of the peripheral blood flow, not just relating to the flowmetric parameters, but also to those more directly connected to the metabolic and functional conditions of the microcirculation. During every single administration, blood flow, skin and muscular temperatures were recorded. As concerned the drug's chronic effect, endurance limit, skin and muscular temperatures, whole blood viscosity, plasma viscosity and red cell filterability were recorded before beginning the treatment and after 15 days. The results of this study show that during a single buflomedil infusion no modifications have been observed in blood flow and muscular temperature, whereas skin temperature showed a slight increase. On the contrary, after a 15 days treatment, muscular temperature and endurance limit significantly increased, without flowmetric changes. A significant decrease in values of blood viscosity at high shear-rate was recorded too. The overall results seem to indicate that after treatment with buflomedil there is an improvement of the metabolic muscular conditions, probably due to a stimulant effect of the drug on microcirculatory blood flow.

[Attenuation of post-ischaemic reactive hyperemia during lifting of the lower limbs]. / Attenuazione dell'iperemia reattiva post-ischemica durante il sollevamento dell'arto.

With a view to determining to what extent changes in the position of the lower limbs influence post-ischaemic reactive hyperaemia, an ischaemic test was run on a group of normal subjects and patients with peripheral obliterative arteriopathy. Reactive hyperaemia was induced both in the usual supine position and then with the leg raised at 60 degrees to the horizontal. Raising of the leg significantly reduced the amplitude and duration of hyperaemia in both groups, though the differences between them with regard to the hyperaemic flow pattern were not affected. Various explanations of the results are offered. Raising of the limb appears to act more on local mechanisms controlling the peripheral arterial flow than on factors responsible for the genesis of RH. In particular, over and above the reduction of hydrostatic pressure, importance may be ascribed to the disequilibrium created by raising the limb on the component of vasal transparietal pressure. In arteriopaths, these factors are made more potent by obstruction of the main limb artery and arteriosclerotic impairment of the colateral circulation. Lastly, emphasis is placed on the possibility that the apparent metabolic deficiency created by ischaemia and remedied by RH is at least partly greater than the real deficiency and the tissues actual metabolic requirements.

Fibrositic myofascial pain in intermittent claudication: significance of trigger areas in the calf.

To test the hypothesis of a myofascial component in intermittent claudication, 56 male patients were studied. Calf blood flow, at rest and during postischemic and postexercise hyperemia, presence of trigger areas, and exercise tolerance were evaluated and compared. The results can be summarized as follows: The exercise tolerance is reduced when trigger areas are present in the calf muscles, and the more severe the trigger areas, the lower is the exercise tolerance. Trigger areas are more severe when the hyperemic flow is more reduced. The peak flow of reactive hyperemia is also correlated to work load. Pain in intermittent claudication is a complex phenomenon. According to the aforesaid results, the severity of limb ischemia and the presence of trigger areas in the calf appear to be the major factors. Besides the two reasons already known, a third is suggested to explain calf claudication: the elective location of trigger points in the gastrocnemius muscle.

Exercise hyperemia for the study of peripheral circulation.

Blood flow in the calf was measured during postexercise hyperemia in normal subjects and in PAD patients by means of a foot ergometer that gives direct reading of the work performed. In normals, first and peak flow increased with the rise of work load up to 100 KGM. The duration of hyperemia increased with a work load of 30 to 200 KGM. In PAD patients, first flow did not coincide with peak flow. Peak flow was lower and delayed, and the duration of hyperemia was more prolonged than in normal subjects. In patients with intermittent claudication, first flow, peak flow, and work load were higher than in patients with rest pain or impending gangrene. Exercise hyperemia appears as a useful test for screening normal limbs from those with arterial obstruction. Since in PAD patients exercise is interrupted when muscular pain appears, it is evident that the earlier the arrest of work and the appearance of pain, the greater is the involvement in the arterial tree of the leg. Therefore the exercise hyperemia test can be used also as a means of evaluating the different stages of PAD.

[Behavior of post-ischemic reactive hyperemia in increasing periods of circulatory arrest in healthy subjects and in patients with peripheral obliterating arteriopathy]. / Comportamento dell'iperemia reattiva post-ischemica per periodi crescenti di arresto circolatorio nei soggetti sani e con arteriopatia obliterante periferica.

Reactive hyperemia was studied by plethysmographic measurement of the blood flow in the calf in normal subjects and in patients with peripheral arterial disease following circulatory arrest for periods ranging between 1 and 20 minutes. The duration of occlusion is an important factor in determining the behaviour of reactive hyperemia. Peak flow increases significantly when there is up to 10 minutes of circulatory arrest. Following release of an occlusion of 15 or 20 minutes, the further rise of peak flow is very moderate. The duration of subsequent hyperemia is greater in patients than in normal subjects, when the length of the occlusion is of 1 to 10 minutes. When circulatory arrest is prolonged for more than 10 minutes, the recovery time of basal flow is significantly greater in normal subjects. Several mechanisms are involved in reactive hyperemia; their relative importance may vary with the duration of occlusion. Circulatory arrest of 3--5 minutes is a useful clinical test to screen patients with arterial occlusive disease. It is not the best for a full evaluation of the blood flow in the lower limbs either in normal subjects or in partients.

Comparison between reactive and exercise hyperemia in normal subjects and patients with peripheral arterial disease.

Reactive and exercise hyperemia were compared in healthy men and in patients with PAD. In both patients and normals the calf blood flow of reactive hyperemia was recorded after a 5-minute ischemia. Exercise hyperemia was measured in normals after variable work loads (30 and 50 kg) and immediately after the occurrence of pain in patients with PAD. In healthy limbs the first and peak flows of exercise and reactive hyperemia are similar. The recovery time for basal flow is prolonged after exercise. However, reactive and exercise hyperemia differ significantly when arterial obstruction due to arteriosclerosis obliterans is present. First flow and peak flow are higher and recovery time more prolonged after exercise. It is also likely that the control mechanisms of the two hyperemic reactions are different. Muscular exercise, when protracted until pain occurs, can produce a metabolic and circulatory adjustment other than that of ischemia. There is experimental evidence to support this hypothesis.

[Blood viscosity and triglyceridemia. Findings using a co-axial cylindrical viscosimeter at low "shear rates"]. / Viscosità ematica e trigliceridemia. Indagini con viscosimetro a cilindri coassiali a basse "shear rates".

Examination of blood viscosity at low shear rates using a co-axial cylinder viscometer showed a significant difference between the means of values observed in hypertrigliceridemic patients compared with that of control subjects. This result differs from what has been reported by most workers although generally greater shear rates have been used. Calculation of the "r" coefficient and plotting of the regression line for each shear rate showed that there is no linear correlation between blood viscosity and triglyceridaemia, whose variations occur quite independently. It is suggested that the absence of a correlation between the two parameters examined may depend on various factors, of which the most important are those pertaining to the rheological properties of red blood cells and to the structure and chemical and physical characteristics of the triglyceride molecule and of the lipoproteins and chylomicrons which transport them.

Effect of a proteinase inhibitor on intermittent claudication or on pain at rest in patients with peripheral arterial disease.

Twenty patients with peripheral arterial disease and 10 normal controls were submitted to i.v. injection of aprotinin, polypeptide (mol.wt. 6512) extracted from bovine lung, in order to examine its effects on: (a) lower limbs pain, (b) lower limbs sensibility, (c) calf blood flow. Aprotinin (100,000 Ku i.v. diluted in NaCl 0.9%) was given in a single dose or twice a day for a week; for control the same subject received, before or after aprotinin, an equivalent volume of diluent (0.9% NaCl). The results demonstrate that aprotinin is able to increase the initial pain limit walking tolerance and to decrease the intensity of pain at rest and of myalgic or "trigger" areas. No variation was observed on skin sensibility and on calf blood flow, both basal resting and hyperemic. The favorable effect of examined polypeptide on ischemic pain can be attributed neither to increase of calf blood flow nor to influence on perception of painful stimuli. It seems therefore to suggest that aprotinin acts on biochemical mechanisms that cause the ischemic pain. Presumably it inhibits kininogenases and tissue protein-hydrolyzine enzymes activated in the course of ischemia.

Behavior of calf blood flow in normal subjects and in patients with intermittent claudication during a 24-h time span.

Calf basal resting and reactive hypercemia blood flow were measured at 4-h intervals during a day in fifteen healthy subjects and in fifteen patients with intermittent claudication by means of a venous occlusion plethysmograph. Mathematical-statistical analysis of the data failed to demonstrate circadian periodicity of calf blood flow in healthy subjects, but proved the existence of a 24-h rhythm of calf basal resting and reactive hyperemia blood flow in patients with intermittent claudication. This different behavior of calf blood flow can be understood if one considers that in healthy subjects the voluntary muscles in the extremities have a blood supply which can be instantaneously adjusted over a large area. In patients with peripheral arterial disease, on the other hand, the vascular responses in voluntary muscles of the limbs to various endogenous or exogenous stimuli are impaired and reduced. The circadian rhythm observed in patients with intermittent claudication has early evening peaks and a nocturnal trough with a nadir occurring after midnight and before 0400. This rhythm displays marked similarities with those of all other circulatory values. As to the mechanism of rhythm, it is hard to decide whether or not it has an independent endogenous origin. It is known that many of the circulatory variables are interrelated and that some are clearly related to other circadian rhythms. Perhaps the rhythmic reduction of limb blood flow which occurs during the night is the mechanism underlying the nocturnal pain of subjects with limb ischemia by peripheral arterial disease.

[Arteriography findings in vibration vascular disease of upper limbs ("vibration angiopahty") (author's transl)]. / Reperti arteriografici nella patologia vascolare da vibrazioni degli arti superiori ("angiopatia da vibrazioni")

A bilateral angiographic study of the upper limbs was carried out under general anaesthesia in a group of 81 subjects--mostly (91.3%) miners--using vibrating tools. The patients' age ranged from 30 to 57 years; the time they worked as vibrating tool operators varied from 5 to 36 years; the duration of symptoms ranged from 3 months to 10 years. The mean values were 46.1, 20.9 and 3.7 years, respectively. Seventy-four subjects (91.3%) complained of Raynaud's-like phenomenon, which in 36 (44.4%) of them was elicited too, although partially, by provocative tests (cold exposure). Angiography was carried out under general anaesthesia maintained with halothane. Bilateral angiograms were available in 61 instances; in the remainder, only either right or left angiograms could be obtained. In all the subjects examined arteriographic lesions were found, mainly represented by organic stenoses and occlusions. The prevalance of such lesions was minimal at the level of the forearm arteries, and maximal at the level of the digital arteries. The 2nd finger, bilaterally, was the most frequently involved; the index finger on either side and the middle one on the right side were the most involved as to severity and extent of lesions. The 1st finger, however, was quite frequently involved too. No definite relationship between prevalance, severity and extent of arterial lesions, on one hand, and some history, clinical and functional parameters (such as age, vibrating tool usage time, smoking habit, hand arterial pattern, pulmonary silicosis, instrumental findings and Raynaud's-like phenomenon), on the other hand, could be established. As to Raynaud's-like phenomenon, it is hypothesized that such a finding could be, at least in part of cases, subsequent to the previous development of organic lesions in the digital arteries.