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Biomedical subjects

A Pfister

Publications and source records attributed to A Pfister.

At least 37 records · Page 2Linked to original sources
PubMed1988

[Effect of long-term administration of platelet activating factor on pulmonary response and morphology in the guinea pig].

The possible role of PAF in the development of bronchial hyperreactivity was investigated using Alzet osmotic minipumps loaded with PAF or solvent alone and implanted in male Hartley guinea-pigs. Compared to animals treated with solvent alone, those receiving PAF (20 micrograms/kg/h for 15 days) exhibited a hyperreactivity to histamine. The lungs from PAF-treated were congestive in appearance, bronchi and the bronchioli were contracted, Reisseissen muscles were markedly hypertrophied and a muciparous metaplasia of the epithelium was observed. In addition, the number of eosinophils was significantly increased in the parenchyma, as was the number of mast cells in the peribronchial regions. These data indicate that long term-treatment with PAF induces profound alterations in the respiratory system resembling those observed in asthmatic patients. They also strengthen the also strengthen the role of PAF in the development of bronchial hyperreactivity.

Animals↗
PubMed1988

[Circadian variations in the incorporation of gamma-aminobutyric acid (GABA) and tritiated taurine into the pineal body of CD mice].

Pineal uptake of two putative neurotransmitters, gamma-aminobutyric acid (GABA) and taurine, was investigated during the 24 h-cycle in mice kept in long (14L/10D) or short (10L/14D) photoperiods. Tritiated mediators were intraperitoneally injected and their concentration both in pineal gland and cerebellum were measured at several times along the nycthemere. A circadian rhythm of exogenous GABA uptake was observed in mice kept in long photoperiods: GABA uptake was high during the night, when the gland was active and low during the day. It corresponded to the pineal cycle of indoleamine synthesis. It was particularly sensitive to sudden changes of lighting. In short photoperiods, a similar cycle was observed but the result was not significant because of individual variations. Taurine uptake did not show such a circadian rhythm either in long or in short photoperiods: it was constant and rather low with large variations from one animal to another.

Animals↗
PubMed1987

Left ventricular ultrastructure in pulmonary stenosis and in tetralogy of Fallot.

Twelve patients underwent haemodynamic studies and myocardial biopsies: 7 with pulmonary stenosis (PS) and 5 with tetralogy of Fallot (TOF). Their ages ranged between 2 and 43 years. Right ventricular pressure was 128 +/- 43 mmHg in PS and 98 +/- 8 mmHg in TOF. Aortic blood oxygen saturation was 97.0% +/- 1.4% in PS, and 88.4% +/- 6.3% in TOF. Left ventricular (LV) weight was normal in TOF while it was increased in PS: 140.7 +/- 74.3 vs 74.0 +/- 8.7 g/m2 (P less than 0.001). Contractility was altered in both PS and TOF: ejection fractions were 56% +/- 7% vs 65% +/- 6% (P less than 0.001). Light microscopy showed abnormal transverse diameter of left ventricular myocytes in both PS and TOF: 18.6 micron +/- 4.0 micron vs 19.4 micron +/- 4.9 micron. The percentage of interstitium was normal: 29.6% +/- 3.9% vs 26.2 +/- 5.1%. Transmission electron microscopic examination revealed hypertrophic changes in all patients and degeneration in 7 of them. Hyperfunctional alterations of the myocytes were characterized by the increased number and reduced size of mitochondria, the enlarged Golgi complex, the increased number of ribosomes, the marked folding and convolutions of the nuclear membrane, the dilatation and tortuosity of T tubules. Myofibrillar lysis was the major degenerative change, which was also observed in the right ventricle (RV) of the same patients. No correlation was observed between these alterations and the patient ages, RV pressures, aortic blood oxygen saturations and ejection fractions. These findings led us to conclude that: (1) suprasystemic pressure overload of the RV induces macroscopic LV hypertrophy; (2) mild and suprasystemic pressure overload of the RV induces hyperfunctional changes in the LV; (3) myocardial degeneration is not related to hypertrophy nor to hypoxia, but is part of a more widespread cardiovascular fetopathy.

Adolescent↗
PubMed1987

[Experimental and clinical results of ultrasound imaging in sports orthopedic soft tissue diseases].

Ultrasound scanning of the shoulders, knee joints, Achilles' tendon and muscles is presented as a noninvasive technique for the diagnosis of joint and soft tissue disorders. In experimental ultrasound studies on shoulders, knee joints, tendons and muscles of cadavers the diagnostic value of the method is assessed. The experimental observations were compared with clinical results collected in three years from 610 patients. Particularly characteristic findings in sports-induced soft tissue lesions are reviewed as examples.

Achilles Tendon↗
PubMed1987

Interactions between granulocytes and platelets with the guinea-pig lung in passive anaphylactic shock. Correlations with PAF-acether-induced lesion.

To compare the bronchopulmonary effects of anaphylactic shock with those of platelet-activating factor (PAF-acether), antigen (ovalbumin) was administered intravenously to passively sensitized guinea-pig. Subsequent lung alterations were assessed histologically. Within 1 min following ovalbumin, bronchial and arterial constrictions were observed, accompanied by platelet thrombi in the pulmonary microcirculation, intravascular leucocyte accumulation with diapedesis, disruption of endothelium and alterations of type II pneumocytes. Free eosinophilic granules were scattered in the bronchial submucosa. One h after the infusion of ovalbumin, platelet aggregates had disappeared, bronchoconstriction was over, and denudation of the bronchial epithelium was observed. These alterations resemble to those induced by intravenous PAF-acether, which led us to compare the effects of inhaled PAF-acether and antigen at bronchoconstrictor concentrations. In both cases, leucocytes were aggregated in the microcirculation within 2 min and persisted 1 h later. Massive infiltration of eosinophils and activation and clumping of alveolar macrophages were also noted. Our findings support the involvement of PAF-acether in acute anaphylaxis in the guinea-pig.

Anaphylaxis↗
PubMed1987

[Demonstration of Langerhans cells in the human bronchial epithelium].

Ultrastructural and immunohistochemical analysis of six specimens revealed for the first time a small number of Langerhans cells in non-neoplastic bronchial epithelium. These cells were usually found either interspersed perpendicularly between columnar epithelial cells or just above the basal lamina with extending cytoplasmic processes. Usually few Birbeck granules, especially located in the Golgi region, were present throughout the cytoplasm. Immunohistochemical studies were performed on semi-thin sections with a polyclonal anti-S-100 protein. The population of S-100 positive cells represented about 1% of all the epithelial cells. Not all ultrastructurally identified Langerhans cells were shown to be positive for S-100 antigen. Our results suggest that Langerhans cells could be a constant cellular constituent for the normal bronchial epithelium. The exact function of Langerhans cells in the respiratory epithelium remains to be investigated, but they may have an immunologic function, such as antigen presentation to T lymphocytes.

Bronchi↗
PubMed1987

[Solid cold thyroid nodule. Current data].

Attitudes adopted when confronted with a solid cold thyroid nodule are analyzed in the light of recent developments in paraclinical data represented essentially by results of immunological, ultrasound and fine needle cytopuncture examinations. The use of these new surveillance technics frequently allows surgery to be deferred, while if on the contrary operation is decided then it usually now involves both thyroid lobes to avoid nodular recurrence and repeat surgery. Postoperative follow up surveillance is essential to ensure individual adaptation of attitude: therapeutic abstention, suppressive or possibly compensatory treatment.

Biopsy, Needle↗
PubMed1987

Congestive cardiomyopathy and spasm of coronary microvascularisation in man. Electron microscopic evidence.

This paper reports our observations of right ventricular biopsies taken from a 23 year old patient with a congestive cardiomyopathy. The ultrastructural examination of these samples revealed coronary capillary and arteriolar spasms, as well as an ischemic aspect of the myocytes. The responsibility of the coronary microcirculation in the genesis of dilated cardiomyopathies has been suspected for a long time. It has recently been demonstrated in the Syrian hamster, but it has never been clearly evidenced in man. The case that we present seems to confirm this hypothesis. The fact that the spasm is a transitory phenomenon and that it most probably does not involve all areas of the myocardium simultaneously could explain the difficulty encountered in observing this phenomenon in endomyocardial biopsies.

Adult↗
PubMed1986

Neuropeptide Y normalizes renin secretion in adrenalectomized rats without changing blood pressure.

In the periphery, neuropeptide Y is present in plasma, in the adrenal medulla as well as in sympathetic nerve endings and in the juxtaglomerular apparatus. The aim of the present study was to assess the effect of this peptide on renin secretion. Normotensive rats were adrenalectomized or sham-operated and made hypertensive with methylprednisolone acetate (20 mg/kg s.c. once weekly). Deoxycorticosterone pivalate (10 mg/kg s.c. once weekly) was also given to prevent mineralocorticoid deficiency. Two weeks after initial surgery, 12 adrenalectomized and 8 sham-operated conscious rats were infused for 30 min with neuropeptide Y (0.1 micrograms/min) whereas 8 other adrenalectomized and 9 sham-operated conscious rats received under similar conditions the vehicle of neuropeptide Y (10 microliter/min). Neither before nor during the infusions was there a significant difference in blood pressure and heart rate between the 4 groups of animals. Plasma renin activity, measured at the end of the infusion, was 30.5 ng/ml/hr in the adrenalectomized group receiving vehicle and 6.3 ng/ml/hr in that infused with neuropeptide Y (p less than 0.001). This latter value did not differ from that found in sham-operated rats. These results suggest that neuropeptide Y may play an important role in regulating renin secretion.

Adrenalectomy↗
PubMed1986

Association with HeLa cells of Campylobacter jejuni and Campylobacter coli isolated from human feces.

We developed a rapid in vitro test for determining the association of Campylobacter jejuni and C. coli with HeLa cells. Association was expressed as a weighted mean of the number of bacteria associated with one cell in an association index (AI). The reproducibility of the AI was checked by repeating the test six times, using four strains chosen at random. Means and standard deviations of the means were 7.3 +/- 1.2, 6.8 +/- 0.9, 1.8 +/- 1.2, and 0.1 +/- 0.2. The experimental conditions for which the results are reliable have been standardized. Among 42 strains from human feces, two groups appeared: for 22 nonassociative strains (52%), AI values ranged from 0.0 to 2.1 (mean +/- SD, 0.5 +/- 0.6); for 20 associative strains (48%), AI values ranged from 3.5 to 8.3 (mean +/- SD, 6.2 +/- 1.4). Of these 42 strains, 17 were clinically documented. Diarrhea occurred more frequently in patients infected with associative strains than in those infected with noninvasive strains (7/7 versus 3/10, P = 0.01). Fever also occurred more frequently in patients infected with associative strains (6/7 versus 2/10, P = 0.03). Transmission electron microscopy and viable counts made after killing of extracellular bacteria by gentamicin support the fact that associated Campylobacter spp. are adherent to the cell membrane and are internalized into cytoplasmic vacuoles. The described test seems to be a convenient and rapid method for estimating the pathogenicity of a given strain.

Bacterial Adhesion↗
PubMed1986

[Normalization of renin secretion by neuropeptide Y in adrenalectomized rats with glucocorticoid-induced hypertension].

In the periphery, neuropeptide Y is present in the circulation, in the adrenal medulla as well as at the level of nerve endings and of the juxtaglomerular apparatus. The aim of the present study was to assess the effect of this neuropeptide on renin secretion. Normotensive rats were biadrenalectomized or sham-operated and made hypertensive with methylprednisolone acetate (20 mg/kg s.c. once weekly). Deoxycorticosterone pivalate (10 mg/kg s.c. once weekly) was also given to prevent mineralocorticoid deficiency. Two weeks after that initial surgery 12 adrenalectomized rats and 8 sham-operated rats were infused for 30 min with neuropeptide Y (0.1 microgram/min) whereas 8 adrenalectomized rats and 9 sham-operated rats received in similar conditions the vehicle of neuropeptide Y (10 microliters/min). At that time, the rats were conscious and there was no significant difference in blood pressure and heart rate between the 4 groups of rats. At the end of the experiment, adrenalectomized rats exhibited a markedly stimulated renin-angiotensin system. Neuropeptide Y made it possible to normalize plasma renin activity in these rats, thus suggesting that neuropeptide Y plays an important role in regulating renin secretion.

Adrenalectomy↗
PubMed1986

[Filamentary granules in human bronchi].

Mucous cells of human bronchial glands contain secretory granules with 5,5-7 nm parallel filaments. In contrast with the glycoproteic-rich mucous granules, filamentary granules exhibit weak reactivity with tannic acid, indicative of proteins. Exocytosis or discharge in glandular lumen are sometimes observed. These original granules may probably represent an additional component of fibrillar matrix in mucus.

Bronchi↗
PubMed1986

[Ultrastructural study of the human bladder trigone].

To assess the ultrastructural appearance of the trigonal epithelium in the young human female, 12 biopsies in the trigonal area have been studied by transmission electron microscopy. The trigonal epithelium is of the stratified squamous nonkeratinizing type and is composed of about twenty cellular layers undergoing a progressive involution from the basal layer toward the surface. In the basal and intermediate layers, Langerhans cells were found, which contain Birbeck granules. As in the urothelium, the intercellular spaces are very distended between the junctional desmosomes. That the trigone has the same embryological origin as the vagina is discussed. It explains the reactivity of the trigonal epithelium to estrogens. Urocytogram is a practical application of these facts.

Adult↗
PubMed1985

Mucoid impaction of bronchi. A scanning electron microscopic study.

An example of mucoid impaction in the culminal bronchus in a potentially asthmatic child is related. Histological sections of the plug showed the characteristic pattern with clusters of eosinophils and other cells within the impacted mucus, which consisted of mainly sulfated glycoproteins. Scanning electron microscopy revealed new data on the three-dimensional structure of the plug. Ten to fifteen micron thick fascicles of partially rolled-up mucous fibres surrounded wide meshes filled with eosinophils and other components. As far as can be determined, this is the first reported ultrastructural description of this particular lesion.

Bronchial Diseases↗
PubMed1985

Experimental infection of gnotobiotic mice with Campylobacter jejuni: colonisation of intestine and spread to lymphoid and reticulo-endothelial organs.

Axenic and monoxenic C3H mice were used to develop an animal model for enteroinvasiveness and translocation of Campylobacter jejuni. After oral administration of 10(7)-10(8) viable cells of C. jejuni on day 0 (D0), bacterial colonisation was followed quantitatively during 23 days by counting free luminal bacteria and tissue-associated bacteria in the duodenum, ileum and colon. The kinetics of bacterial colonisation were the same in axenic and monoxenic mice; bacteria were more numerous in distal than in proximal intestinal segments. Electronmicroscope studies of axenic infected mice showed C. jejuni free in the intestinal lumen on D2 and D7, and adhering to microvilli or included in enterocyte vacuoles in the colon on D2 without inflammatory reaction; C. jejuni was isolated from mesenteric lymph nodes until D23, but from blood, spleen, liver and bile until D1 only. In monoxenic infected mice, C. jejuni was found from D1 to D4 in mesenteric lymph nodes and Peyer's patches, whereas the associated bacterium (Clostridium perenne) was never cultured from any organs. On the basis of our observations in this gnotobiotic model, C. jejuni appears to be an enteroinvasive bacterium with a particular affinity for lymphoid organs.

Animals↗
PubMed1985

Ultrastructural evidence for extravascular platelet recruitment in the lung upon intravenous injection of platelet-activating factor (PAF-acether) to guinea-pigs.

Bronchoconstriction and degenerative lesions of the bronchial epithelium were observed microscopically 1 min after the i.v. injection of 100 ng/kg of platelet-activating factor (PAF-acether) to the anaesthesized guinea-pig. Constricted arterioles containing marginated polymorphonuclear neutrophils and platelet aggregates were seen, as well as alveolar capillaries obstructed by thrombi formed by partially or totally degranulated platelets. Three minutes after the injection of PAF-acether, platelet diapedesis to the alveolar septa and lumen was clearly observed. Bronchoconstriction was still present at 3 min, but subsided after 60 min, whereas oedema of the submucosa persisted accompanied by an infiltration of eosinophils and neutrophils. The infusion of prostacyclin prevented the formation of platelet aggregates and platelet diapedesis due to PAF-acether, but the morphological evidence of bronchial constriction was not modified. Aspirin failed completely to modify the effects of PAF-acether. Our results show that PAF-acether causes early formation and deposition of platelet aggregates, accompanied by the margination of polymorphonuclear neutrophil leucocytes in pulmonary vessels of the guinea-pig. Since bronchoconstriction persisted when platelet aggregation was inhibited with prostacyclin, aggregation by itself would not account for this effect. Early platelet diapedesis in the vicinity of bronchial smooth muscle corroborates previous evidence that platelets contain and release bronchoconstrictor substances, which operate by cyclo-oxygenase-independent mechanisms and are possibly involved with the physiopathology of lung inflammation during immediate hypersensitivity.

Adenosine Diphosphate↗