More on false thrombocytopenias: EDTA-dependent pseudothrombocytopenia associated with a congenital platelet release defect

Natural metabolite glycine administered per os to rats in the fetus period of pregnancy in a dose of 1 mg/kg was found to exert a corrective action with respect to the toxic effect of ethanol in the mother-fetus system. Glycine prevents loss in the body weight, normalizes functional state of the nervous system and metabolic disorders in the maternal organism, improve the redox processes in the lymphocytes changed under alcoholization, and protect the fetus both on the metabolic and microstructural levels.     

Phosphorylation of myosin light chain in resting platelets from NIDDM patients is enhanced: correlation with spontaneous aggregation

Platelet function in patients with NIDDM is enhanced. We have found that spontaneous aggregation (i.e., the formation of small-sized aggregates in the absence of agonist stimulation) occurs at a high rate in platelets from NIDDM patients. We then investigated basal myosin light chain 20 (MLC) phosphorylation, which plays a key role in platelet shape change and aggregation, using a monoclonal antibody against a phosphorylation site (serine 19 residue) in the MLC molecule in platelets from these patients. Standard calibration curves obtained from purified MLC or the phosphorylated form of myosin light chain 20 (MLC-P) were linear within the range of 0-150 ng for MLC and 0-3 ng for MLC-P. The amount of MLC or MLC-P in platelets was estimated, and basal MLC phosphorylation was calculated. Platelets were obtained from 9 young healthy control subjects, 13 age- and sex-matched nondiabetic control subjects, and 13 patients with NIDDM. The basal MLC phosphorylation in platelets was significantly higher in the NIDDM patients than in the control subjects, irrespective of age. These findings suggest that platelets from NIDDM patients are activated in vivo. Platelets obtained from NIDDM patients generated spontaneous aggregation, the degree of which was significantly higher than that in control subjects. Platelet spontaneous aggregation correlated well with basal MLC phosphorylation. These findings suggest that increases in basal MLC in platelets may be one factor leading to hyperaggregability of platelets in these patients.     

Localization and translocation of MMP-2 during aggregation of human platelets

We have previously shown that human platelets express matrix metalloproteinase-2 (MMP-2) and that the release of this enzyme during platelet activation mediates the ADP- and thromboxane-independent part of aggregation. We have now used immunogold electron microscopy, flow cytometry. Western blot analysis and zymography methods to study the ultrastructural localization of MMP-2 in human washed platelets. Platelet aggregation was stimulated by collagen and the MMP-2 immunoreactivity of platelets was followed during various stages of aggregation. In resting platelets, MMP-2 was randomly distributed in the platelet cytosol without detectable association with platelet granules. Platelet aggregation caused the translocation of MMP-2 from the cytosol to the extracellular space. During the early stages of aggregation, MMP-2 remained in close association with the platelet plasma membrane. We conclude that the interactions of MMP-2 with platelet surface membranes mediate the aggregatory response induced by this enzyme.     

Platelet aggregation in patients treated with diflunisal

The effect of the non-steroidal analgesic diflunisal on platelet aggregation and clinical haemorrhage at a dosage 250 mg twice or 3-times daily, sufficient to relieve musculo-skeletal pain and other painful conditions, was studied in 15 patients and 5 normal subjects. Platelet aggregation was carried out with ADP and collagen before and during treatment with diflunisal. The results indicated that diflunisal is an effective analgesic with no significant adverse effect on platelet function or clinical bleeding.     

Adhesion and aggregation of neutrophils in patients with unstable angina

The adherence and aggregation abilities of neutrophils (PMNs) were evaluated in thirty three patients with unstable angina, who were qualified for PTCA procedure. The control group consisted of forty one clinically healthy persons. The blood for investigations was obtained from coronary sinus and basilic vein just before the procedure, while in the control group from basilic vein only. The adherence of PMNs to plastic surface (rest and stimulated by PMA) was estimated in vitro according to Oez's et al. method by measuring optical density of generated formazan, whereas the aggregation of PMNs was evaluated using the leukergy test according to the method of Fleck in Berliner's and Aronson's modification. In patients with unstable angina statistically significant higher (p < 0.001) adherence of peripheral blood PMNs, compared with control groups was found (patients: rest-0.525 +/- 0.245, stimulated-0.839 +/- 0.419, control group: rest-0.260 +/- 0.129, stimulated-0.522 +/- 0.377). The aggregation of peripheral blood PMNs was significantly higher (p < 0.05) in the sick than in the control group (the sick-10.98 +/- 4.29%, controls-4.65 +/- 3.01%). No differences in investigated parameters of PMNs obtained from peripheral or coronary sinus blood were found.     

Two distinct mechanisms of inhibition of platelets aggregation by acetylsalicylic acid

The von Willebrand Factor-Ristocetin adduct activates Platelets aggregation and secretion. Acetylsalicylic acid inhibits Platelets activation by two distinct mechanisms indicating that the adduct activates Platelets by triggering at least two distinct intraplatelet metabolic pathways. The first starts from the activation of Phospholipase A-2 that produces Arachidonic acid, which, in turn, undergoes the metabolic pathway leading to Thromboxane A-2; this pathway can be blocked by the intraplatelet Acetylsalicylic acid by irreversible inactivation of Cyclooxygenase but it is insensitive to the extra-platelet Acetylsalicylic acid. The second pathway is triggered by intact von Willebrand Factor, but not by the Acetylsalicylic acid-treated one; it is insensitive to intraplatelet Acetylsalicylic acid and therefore unrelated to the Arachidonic acid metabolism.     

Comparison of the number of dense bodies in blood platelets in patients with myocardial infarction

Dense bodies present in blood platelets contain also serotonin, which together with other factors stimulates vasoconstriction. This paper presents an investigation of possible differences in the number of dense bodies in platelets of patient R.T., affected by two myocardial infarctions resulted in death, with the number of dense bodies in platelets of patient L.T., affected by the same type of myocardial infarct, however, without complications. Dense bodies were labelled with mepacrin and viewed and counted under the fluorescence microscope. Score for each type of platelet (containing 1-6 dense bodies) as well as a total score for each of 3 blood samples collected during acute phase of the infarct and then after 5 and 10 consecutive days were calculated. Increased number of dense bodies (6 per platelet) was seen in patient R.T. Also the total score was the highest. For comparison total score was calculated in an healthy person.     

Galactose-specific lectin from Viscum album as a mediator of aggregation and priming of human platelets

Galactose-specific lectin from Viscum album (VAA) was found to induce aggregation of human platelets in a dose- and sugar-dependent manner. Small nonaggregating concentrations of VAA primed the response of platelets to known aggregants (ADP, arachidonic acid, thrombin, ristocetin, and A23187). VAA-induced platelet aggregation was completely reversible by addition of the sugar inhibitor lactose and the platelets from disrupted aggregates maintained the response to other aggregants. The lectin-induced aggregation of washed platelets was more resistant to metabolic inhibitors than thrombin- or arachidonic acid-dependent cell interaction. In contrast to the related galactose-specific lectin from Ricinus communis and the soy bean agglutinin, the lectin did not aggregate liposomes prepared from total platelet lipids, indicating different affinities of aggregation-mediating lectins to platelet glycolipids.     

Leukocyte aggregation in patients with a previous cerebral ischemic event

BACKGROUND AND PURPOSE: The role of leukocyte aggregation in ischemic stroke is controversial. In this study we investigated this hemorheologic alteration in patients at risk for stroke. METHODS: Leukocyte aggregation was evaluated with the leukergy test in 61 patients with a recent cerebral ischemic event and in 61 control subjects. RESULTS: In patients leukocyte aggregation was significantly higher than in control subjects (3.8 +/- 3.4% versus 2.5 +/- 2.2%; P = .01). In control subjects, the presence of vascular risk factors was associated with values of aggregation similar to those observed in patients. CONCLUSIONS: These findings suggest an association between altered leukocyte aggregation and cerebrovascular disease. Further investigations are needed to evaluate whether this hemorheologic alteration can be considered a marker of increased risk for stroke.     

Whole blood platelet aggregation and coagulation factors in patients with systemic sclerosis

It is unclear whether the changes in platelet function which are observed in systemic sclerosis are a primary characteristic of this disease or whether they occur secondary to vascular changes. Whole blood platelet aggregation was studied in 26 patients with systemic sclerosis, normal subjects matched for age, sex and secondary characteristics, 19 patients with Raynaud's disease and 19 patients with systemic lupus erythematosus. Plasma levels of fibrinogen, von Willebrand factor antigen and factor VIII:C were also measured. Systemic sclerosis was associated with a significant (P > 0.001) enhancement of the sensitivity of platelets to collagen. In contrast, significant enhancement of the response to either ADP or adrenaline was not observed. Enhanced sensitivity to collagen was not associated with the presence of either Raynaud's disease or systemic lupus erythematosus. Systemic sclerosis was associated with significantly raised levels of von Willebrand factor antigen and fibrinogen. On an individual patient basis, von Willebrand factor antigen was related to the severity of the disease whereas platelet sensitivity to collagen was not. In conclusion, this study suggests that the enhanced sensitivity to collagen which occurs in systemic sclerosis is due to a primary change in the platelet and that this change can combine with elevated levels of adhesive proteins.     

Effects of divalent cations on calcium levels, aggregation and morphology of human blood platelets in vitro

Some effects of cadmium, nickel, strontium and manganese ions upon human platelets in vitro are reported. Both Mn and Cd induced aggregation, Mn being the most effective. Ni and Sr did not have this effect. Scanning electron microscopic observation showed that Mn and Cd, but not Ni and Sr induced shape changes in the platelets. X-ray microanalysis of pyroantimonate fixed platelets revealed that calcium was displaced from both membrane and cytoplasmic regions by all four cations. The magnitude of displacement occurred in the sequence Mn > Cd > Ni approximately or equal to Sr. Manganese was detected both in the cytoplasm and membrane region of those platelets treated with this ion. It is suggested that the cations are influencing directly certain macromolecular ligands whose condition controls platelet surface properties.     

Difference in inhibitory actions of products of the myeloperoxidase- catalyzed reaction on initial aggregation of activated platelets]

Response characteristics of neurons in the gustatory and visceral zone of the parabrachial nucleus (PBN) to gamma-aminobutyric acid (GABA) were examined using whole cell recordings in brain slices of the rat. Based on the recording site, neurons were divided into three groups: neurons in the dorsolateral quadrant of the PBN (DL-neurons), neurons in the dorsomedial quadrant of the PBN (DM-neurons) and neurons in the ventromedial quadrant of the PBN (VM-neurons). Recordings were made from 44 DL-, 43 DM-, 39 VM-neurons. Superfusion of GABA resulted in a concentration-dependent reduction in input resistance in 67.5% of the neurons in the PBN (73.1% of the DL-, 62.5% of the DM-, 66.7% of the VM-neurons). No obvious difference of the concentration-response curve was found among three groups. The mean reversal potential of the GABA effect was about -74 mV and no significant differences were observed among three groups of neurons. The GABA response was partly or completely blocked by the GABAA antagonist bicuculline in all neurons tested. Superfusion of the GABAA agonist muscimol resulted in a decrease of the input resistance in all neurons tested. It was concluded that GABA functions as an inhibitory neurotransmitter in both gustatory and visceral part of the PBN, mediated in part, by GABAA receptors.     

Blood platelets in severely injured burned patients

Unbelievable decrease of blood-platelet in the severely burned patients during the treatment of skingrafting caused two patients to unexpected death. From the records of changes of platelet number, a certain 'platelet curve' was made. By observing the curve, our treatments of skingrafting were carried out during the stable period and from then on we had no death cases.     

Protein kinase C in platelets of depressed patients

Though described in 1769, the etiology of Zenker's diverticulum remains unclear. Various primary esophageal motor disorders have been proposed, but no consistent manometric pattern or anatomic etiology has been uniformly recognized. An association with clinical neurologic disease at our institution prompted a review of 12 cases of Zenker's diverticulum in patients over 60 years of age, treated in the last 8 years. Nine patients (75%) underwent cricopharyngeus myotomy and diverticulectomy, with uniformly good results. Ten patients (83%) had an associated neurologic disorder, substantiated by cranial CT or MRI, in most cases. A wide range of neurologic problems were identified, but a strong trend toward brainstem or basilar lesions was present. As expected, the etiology of the neurologic abnormality in most patients in this group was cerebrovascular disease, but two patients had peripheral neuropathies. We suggest that the etiology of Zenker's diverticulum in the elderly may be neurologic in origin. Esophageal motor disorders, including incomplete upper esophageal sphincter opening and increased hypopharyngeal pressures, which may result in Zenker's diverticulum, may be a manifestation of central or peripheral neurologic disease in the elderly.     

Enhanced calcium response to serotonin in platelets from patients with affective disorders

The additional use of the palmaris longus tendon is presented with the composite radial forearm-palmaris longus free flap, as useful for improving the final cosmetic appearance. This flap has the additional advantage of avoiding gravitational descent, which is a common problem encountered with many free flaps in head and reconstructions. A clinical case is also presented as an example of this approach.     

Suppressed anti-aggregating and cGMP-elevating effects of sodium nitroprusside in platelets from patients with stable angina pectoris

Short bowel syndrome (SBS) in the newborn results in limited intestinal absorptive capacity, leading especially to fatty acid (FA) malabsorption. It is unknown whether adaptation occurs in time in FA absorption, and whether this adaptation is chain-length dependent. The aid of the present study was to prospectively evaluate FA absorption and excretion during SBS in the newborn. Twenty-one neonates who underwent small bowel resection (of variable length) for various reasons (necrotizing enterocolitis, intestinal atresia, meconium peritonitis, cloacal extrophy, etc) were studied. Eight neonates had SBS, defined as a small bowel remnant of less than 50% of the original small bowel length related to gestational age. The mean remaining small bowel length in the SBS group was 34% (24% to 42%). The non-SBS control group consisted of 13 neonates who had only minor small bowel resections. The mean remaining bowel length for the non-SBS group was 95% (70% to 100%). The results show that the total fractional excretion of FA (FE-FA) at 2 weeks and 1, 2, 3, and 4 months postsurgery was 51% +/- 37%, 33% +/- 24%, 51% +/- 65%, 53% +/- 27%, and 7% +/- 2% in patients with SBS, versus 12% +/- 8%, 24% +/- 10%, 9% +/- 3%, 8% +/- 3% and 17% +/- 14% in the non-SBS controls, respectively (P < .05 by ANOVA). There appeared to be an amelioration in time in FA absorption, especially in the SBS group, after 3 months. FE-FA was chain-length related, being considerably less for C10 and C12 than for C14 and longer amounts. An amelioration of absorption occurred in the SBS patients, especially with the longer-chain FA. On the basis of the study data, the authors conclude that in the initial adaptation phase shorter chain lengths are better absorbed than longer chain lengths; however, in the latter FA group, substantial adaptation occurs with time.