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PubMed1983

Vascular abnormalities in lichen aureus.

Lichen aureus is an infrequently reported subset of the pigmented purpuric dermatoses. A review of the English literature suggests the golden to purple colored lesions are asymptomatic or mildly pruritic with no regression once established. A case report of a 56-year-old man with lichen aureus of the thighs is presented. This case is unusual in that the patient had persistent pain at the lesion site. Furthermore, increased capillary fragility and koebnerization were both demonstrated. Treatment of an asymptomatic urinary tract infection resulted in temporary subjective and objective improvement.

Capillary Fragility↗
PubMed1976

Use of conjugated estrogens in eye diseases.

Presomen, a preparation of natural conjugated estrogen has been applied to 81 ophthalmologic patients. Some patients received it as a preoperative measure for the prevention of hemorrhages, others were treated with the drug in order to facilitate the absorption of vitreous and retinal hemorrhages. The effect of the preparation on capillary fragility has likewise been studied. The literature contains contradictory reports on the mode of action of conjugated estrogens. Clinical observations show conjugated estrogens suitable for the prevention of hemorrhages in connection with surgical interventions.

Capillary Fragility↗
PubMed1977

Amelioration of endothelial abnormalities by prednisone in experimental thrombocytopenia in the rabbit.

Experimental thrombocytopenia results in endothelial alterations associated with bleeding. In this study prednisone was shown to prevent or reverse these changes, which supports the clinical inference that adrenocorticosteroids decrease capillary fragility in thrombocytopenia. Rabbits (3-4 kg), intraperitoneally injected with busulfan, developed 98-99% reductions in platelet count and hemorrhaged profusely. Orally administered prednisone (0.2 mg/kg or 1.0 mg/kg daily) reduced bleeding despite persistent thrombocytopenia. Tongue biopsies obtained after 3 days of prednisone treatment were examined by electron microscopy. Normal rabbits served as controls. 25 consecutive capillaries or venules from each of four animals in the control group and each of five experimental groups were examined for fenestrations, "thin spots" (<800 A thick), and mean wall thickness as determined by planimetry. Vessels from control animals had no thin spots or fenestrations, and the mean vessel wall thickness was 4,254+/-105 A SEM. The 100 vessels from the thrombocytopenic animals had a mean vessel wall thickness of 2,081+/-218 A (P < 0.001), and 42 had thin spots of fenestrations. After administration of the smaller dosage of prednisone, the mean vessel wall thickness increased to 3,556+/-40 A (P < 0.001), and only nine vessels had thin spots or fenestrations. With the larger dosage, only six vessels had thin spots or fenestrations and the mean vessel wall thickness of this group increased to 3,704+/-206 A (P < 0.005). All preparations demonstrated normal endothelial junctions. The data are consistent with the hypothesis that the bleeding of thrombocytopenia is caused by altered capillary and venule endothelium and that diminished bleeding observed with prednisone administration results from amelioration of these endothelial changes.

Animals↗
PubMed1976

Familial bleeding tendency and tonsillectomy.

A retrospective study of 2,292 tonsillectomies revealed 12 cases of hereditary capillary fragility. These cases showed an increased morbidity from bleeding complications and accounted for 4.8 per cent of those with a secondary hemorrhage. When diagnosed, skin bleeding time should be carried out at the time of premedication, and, if prolonged, the procedure postponed.

Adult↗
PubMed1974

Ascorbic acid deficiency in malignant diseases: a clinical and biochemical study.

In a study of the vitamin C status of 50 patients with malignant disease, 46 had leucocyte levels less than the lower limit of the normal range (18-50,μg/10(8) W.B.C.) and of these 30 had very low levels (< 12.5 μg/10(8) W.B.C.). Physical signs compatible with subclinical scurvy were frequently recorded and there was a significant decrease in capillary fragility in those with the lowest levels. Most patients had an inadequate dietary intake of ascorbic acid-containing foods and this was felt to be the major factor in producing the vitamin depletion.

Adult↗
PubMed1990

[Multivariate analysis for the understanding of typical diabetic hemostasis criteria. 2. Prevalent thrombocytic markers].

Various thrombocyte functions and metabolic criteria were investigated in 309 test persons, among them 198 Patients affected with diabetes mellitus, 67 of type I and 131 of type II as well as 111 healthy control persons. From the variety of these factors an optimal amount was determined by means of the statistical method of multivariance analysis separating both types of diabetes and healthy control persons. In addition to haemoglobin A1 concentration, thrombocyte parameters have been found together with the degree of capillary fragility, adrenalin-induced aggregation, platelet aggregation test and clot retraction, which allow individuals to be assigned diagnostically to various groups of test persons. Thus, thrombocyte functions found in both types of diabetes and normal persons exhibit differences which may contribute to a diagnostic classification.

Adult↗
PubMed1984

Haemostatic studies in osteogenesis imperfecta.

Two-thirds of osteogenesis imperfecta (OI) patients claimed that they bruised easily. We have studied haemostasis in 58 subjects with OI, tarda type. The most frequent abnormalities were increased capillary fragility (35%), decreased platelet retention (33%) and reduced factor VIII R:Ag (23%). Reduced ristocetin cofactor, deficient platelet aggregation induced by collagen and prolonged bleeding time were less common findings. The combination of vascular, platelet related and plasmatic defects may reflect that OI is a heterogeneous group of disorders with common clinical expression. The tourniquet test is the most valuable screening test of the haemostatic defects observed in OI.

Adolescent↗
PubMed1982

The effect of prednisone on platelet function tests.

Ivy bleeding time, capillary fragility, threshold ADP concentration for secondary platelet aggregation and platelet adhesiveness were found to be unchanged by 2 d and 6 weeks of treatment with prednisone in 22 consecutive patients with collagen or haematological diseases. Initial high platelet counts were unchanged after 2 d of treatment, but after 6 weeks of treatment the increase was significant. It is concluded that in patients of this category a 6-week treatment with commonly used doses of prednisone does not significantly affect platelet function.

Antigens↗
PubMed1981

Standardization of platelet function tests.

Methods for the standardization of several currently used platelet function tests (bleeding time, capillary fragility, platelet retention, platelet aggregation, platelet factor 3, and platelet volume profiles) are presented, Different variables than may interfere with the reproducibility of the results of each assay were identified and standardized. Using the standardized techniques, the range of normal values for each test was determined in a large population of normal volunteers and used to identify disease states by comparing patient results with those of the normal population. A format for presenting the entire profile of platelet function parameters is proposed.

Adult↗
PubMedDate not supplied

A prospective study of cerebrovascular disease in Japanese rural communities, Akabane and Asahi. Part 1: evaluation of risk factors in the occurrence of cerebral hemorrhage and thrombosis.

An epidemiological study of cerebrovascular disease in Akabane and Asahi, Japan, was made. (These cities are located near Nagoy, Japan.) The study population included 4,737 men and women aged 40 to 79 at the time of entry into the study. There were 4,186 persons who were examined and, of these, 264 cases of cerebrovascular attacks were observed between 1964 and 1970. The incidence rate of stroke in those persons not responding to the survey was 15.9 times higher than in those persons examined according to person-year observation in Akabane. The risk factors for cerebral hemorrhage and thrombosis were evaluated by age-adjusted and sex-adjusted relative risks. The predisposing factors to cerebral hemorrhage appeared to be high blood pressure, high left R wave, ST depression, T abnormality, capillary fragility counts, previous medical history of stroke and albuminuria. For cerebral thrombosis, the predisposing factors appeared to be high blood pressure, ST depression and funduscopic sclerotic findings, and those factors assumed to be significant were glycosuria and smoking habits. Ocular funduscopic abnormality was the most prominent risk factor for cerebral thrombosis, while high blood pressure and ECG abnormalities were highly related to cerebral hemorrhage. It was suggested that those subjects with a relatively higher blood pressure may have a higher relative risk of cerebral hemorrhage than those with a lower (normal range) blood pressure. A previous or family history of stroke also appeared significantly related to cerebral hemorrhage.

Adult↗
PubMed1991

[Posterior fossa hemorrhage 11 years after the use of silastic dural substitute: case report].

A case of posterior fossa hemorrhage is reported. The hemorrhage occurred 11 years after posterior fossa craniotomy with closure using a graft of silastic dural substitute. This 14 year-old girl underwent suboccipital craniotomy at the age of 3 years because of traumatic posterior fossa hemorrhage. The dura mater was repaired with a piece of dural substitute. Eleven years later, she developed severe headache and vomiting. Computerized tomography scanning revealed a high density area in the right posterior fossa. At exploration, a fresh clot was evacuated between the dural graft and the fibrous scar tissue. The resected fibrous scar tissue was 1cm thick, and was adhering to the duro glial scar tissue. Her postoperative course was uneventful, and she was discharged 2 weeks after surgery. Microscopic examination of the fibrous scar tissue revealed an outer layer of loose connective tissue with numerous capillaries. The inner layer consisted of dense connective tissue. It was speculated that fragile capillaries of fibrous scar tissue caused this hemorrhage. Surgeons should not forget this complication although silastic dural substitute is less used than it used to be.

Adolescent↗
PubMed2006

The honeycomb-like structure of the bird lung allows a uniquely thin blood-gas barrier.

Flying requires enormous energy and some birds have higher mass-specific maximal oxygen consumptions than any mammal. The bird lung is very efficient partly because of an extremely thin blood-gas barrier so that some birds have thinner barriers than any mammals. We show here that in addition to the total barrier being very thin, the interstitium which is responsible for the barrier's strength is extraordinarily thin. This observation is paradoxical because intense exercise raises the pressure in pulmonary capillaries and results in large stresses in the capillary walls thus predisposing them to structural failure. For example, all galloping racehorses break their pulmonary capillaries. We propose that the explanation for how the bird can be so highly energetic yet also have such apparently fragile capillaries is the mechanical support provided by the dense packing of rigid air capillaries around the blood capillaries in the gas exchanging region of the lung. This architecture is very different from that in the mammalian lung.

Animals↗
PubMed2000

Silicate polymerization for the preparation of bed-retention frits in capillary electrochromatography

Bubble formation, which is associated with bed-retention frits, is a critical experimental problem in capillary electrochromatography systems. In this investigation, porous silica frits were prepared via spot-heating of a silicate solution, and the effects of several experimental parameters on their performance were studied. The optimal sodium silicate concentrations were 10.8% and 5.4% (w/v) for outlet and inlet frits, respectively. The heating times were 5-6 s for outlet frits and < 1 s for inlet frits. Under optimized conditions, outlet frits were 75 microns (+/- 12 microns) and the heat treatment did not make the capillary fragile at the frit location. Bubble formation was affected by frit length, density, and silanization of the frits with trimethylchlorosilane. Packed capillaries with optimized frits were used successfully in a commercial CE instrument over a normal working day without pressurization, at relatively high ionic strengths (10 mM), and over a wide range of acetonitrile compositions (20%-80%). Currents were also stable for > or = 3 h under very high current (27 microA) conditions. As part of this study, the efficiency and reproducibility of packed capillaries were also briefly evaluated.

Journal Article↗
PubMed1984

The endoendothelial fibrin lining as the crucial barrier and the role of fibrin(ogenin) gels in controlling transcapillary transport.

The interface between the two portions of the 'vessel-blood organ', viz., the vessel wall and the circulating blood, is considered by the author to be the endoendothelial fibrin lining (EEFL). The view that the endothelium, consisting of the endothelial cells and the interendothelial cement substance, is the primary filtration barrier in capillary permeability (CP) is no longer tenable. There is considerable evidence that the primary barrier is an endocapillary protein layer, originally postulated by Danielli in 1940. Copley considered this layer to be identical with the EEFL formed in the more or less immobile portion of the plasmatic zone in close proximity to the vessel wall. Processes of fibrin formation and fibrinolysis can occur there homeostatically, undisturbed by the flow of blood. The fibrinopeptides and plasminopeptides, freed at this site by the conversion of fibrinogen to fibrin and of plasminogen to plasmin, respectively, were reported by Copley et al in 1966 to augment CP. These peptides thus take part in the steadily occurring normal physiological CP. This is facilitated by the porosity of the EEFL due to the network or gel structure of fibrin strands. The author's concept that the EEFL acts as the primary barrier, controlling transendothelial transport and transport across the basement membrane (BM), is discussed on the basis of older and recent findings by several investigators. In particular, the BM is dealt with in some detail as a barrier. Emphasis is placed on the existence of fibrin as a main constituent of the BM, hitherto not generally known. This was demonstrated by direct evidence in the production of (non-thrombocytopenic) vascular purpura with fibrin antiserum. Numerous tiny foci of fibrin(ogenin) gels are expected to stud the BM. Augmented capillary fragility (CF) due to increased fibrinolysis of many of these focal fibrin gels result in petechial hemorrhages. CF and CP are physical properties of the blood capillary wall which behave antagonistically and are controlled by fibrin formation and fibrinolysis, steadily occurring in the vascular layers including the BM. This barrier secures the integrity of the capillary wall by preventing extravasation of blood or hemorrhages. New experimental approaches to verify the detection of fibrin in the microstructure of the capillary wall are proposed. Moreover, hemorheological experimentation, models and treatments are needed to establish whether or not the EEFL is the crucial, critical barrier in CP, as proposed.

Animals↗
PubMed2003

Germinal matrix-intraventricular hemorrhage in the premature newborn: management and outcome.

Germinal matrix-intraventricular hemorrhage (GMH-IVH) in the premature newborn results from rupture of fragile capillaries in the germinal matrix. Its pathogenesis is multifactorial and relates principally to a pressure-passive cerebral circulation, fluctuations in cerebral blood flow, and derangements of coagulation and fragility of the germinal matrix microvasculature. Several interventions have beneficial effects for prevention of GMH-IVH. Outcome after GMH-IVH relates largely to the severity of hemorrhage, the extent of hemorrhagic and ischemic parenchymal involvement, and complications (e.g., posthemorrhagic hydrocephalus). Even in the absence of neuroimaging abnormalities, VLBW infants have a high incidence of academic and behavioral problems which persist into adolescence and early adulthood.

Cerebral Hemorrhage↗
PubMed1986

Human thrombocytopenia is associated with structural abnormalities of the endothelium that are ameliorated by glucocorticosteroid administration.

Capillary fragility is characteristic of severe thrombocytopenia. This mechanical weakness may not be solely accounted for by decreased ability of platelets to repair endothelial breaks. Platelets may have a role in maintaining endothelial hemostasis. This laboratory has demonstrated thinning of capillary endothelium in experimental thrombocytopenia. We now report similar findings in human thrombocytopenia. Capillary endothelium supplying either skin or skeletal muscle was found to have a mean thickness only half that of normal as well as frequent very thinned areas, including some fenestrations. All findings reverted toward normal after four days of prednisone administration at a time the degree of thrombocytopenia was equally severe. These findings are consistent with the hypothesis that platelets are necessary for normal structure and function of endothelial cells and that glucocorticosteroid administration may ameliorate the pathophysiology of thrombocytopenia.

Adolescent↗