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Biomedical subjects

J Lazarchick

Publications and source records attributed to J Lazarchick.

At least 37 records · Page 2Linked to original sources
PubMed1989

The laboratory diagnosis of lupus anticoagulants.

With the well-documented association of lupus anticoagulants with thrombotic disease and recurrent spontaneous abortion, the laboratory approach to diagnosing these inhibitors is more critical now. To this end, we examined plasma samples from 21 patients who initially presented with a prolonged prothrombin time or activated partial thromboplastin time or both for the presence of lupus anticoagulants. We used a battery of coagulation tests, including both immediate and two-hour mixing studies, a platelet neutralization procedure, a tissue thromboplastin inhibition test, and dilute Russell viper venom times. Two patients (10%) had only a prolonged prothrombin time, seven (33%) had only a prolonged activated partial thromboplastin time, and in 12 (57%) both were abnormal. In 15 patients, inhibition was evident on immediate assay of equal-volume mixture studies of patient plasma and normal pooled plasma, but in three additional patients it was evident only after a two-hour incubation. Fifteen of 18 samples showed correction of the abnormal screening study when platelets were used as a source of phospholipid. Both the tissue thromboplastin inhibition test and dilute Russell viper venom times were sensitive assays, being abnormal in 20 of 21 and 13 of 14 samples, respectively. In four patients, discordance of studies necessitated specific coagulation factor levels being measured to confirm the presence of the inhibitor. Because of the variable effect of the inhibitors on all currently available assay procedures, we would suggest that any evaluation will require a laboratory to have a battery of tests available before such an inhibitor can be excluded.

Adolescent↗
PubMed1989

Health care history and utilization for Atlantans who died homeless.

A limited study of 18 deaths among homeless persons in Atlanta, Georgia, has shown that about two-thirds had utilized public health care facilities prior to their death, often over a period of many years. Utilization of two available, specific clinics for the homeless could not be demonstrated. The county hospital and alcoholism treatment center accounted for all documented episodes of health care. Formal, medical documentation of significant alcohol-related morbidity was shown in 50% of those who died homeless. Other common medical problems included seizure disorders, hypertension, pneumonia, chronic pulmonary disease, and non-lethal trauma. These data may be used practically during medico-legal death investigation and by public health agencies when planning policy and procedure relevant to the homeless population. Paucity of data concerning mortality in the homeless should prompt additional, region-specific studies to determine risk factors in areas where homelessness is manifest.

Adult↗
PubMed1988

Acquired von Willebrand's syndrome associated with an extranodal pulmonary lymphoma.

A case of acquired von Willebrand's syndrome associated with an extranodal pulmonary lymphoma is reported in a 58-year-old man. His initial factor VIII-von Willebrand factor (vWF) complex parameters included a factor VIII activity of 29 U/dL, a vWF protein of 17 U/dL, and a ristocetin cofactor of less than 10 U/dL. A specific factor VIII inhibitor could not be demonstrated in mixtures of his plasma and normal pooled plasma nor could immune complexes of IgG-factor VIII be detected in similar mixtures using protein A in a solid phase. Following surgical removal of the patient's tumor, all factor VIII-vWF complex parameters returned to normal. Immunoperoxidase stains of the lymphoid tumor cells were negative for von Willebrand protein. The patient's acquired von Willebrand's syndrome recurred approximately one year later, presumably indicative of recurrent lymphoma.

Factor VII↗
PubMed1988

Utility of frozen platelets for a platelet antibody assay using flow cytometric analysis.

The immunoreactivity of a PLA1 antibody-containing serum to frozen/thawed platelets prepared by four different procedures was measured to assess the practicality of preparing a platelet reagent that could be easily stored and readily used in an immunofluorescent platelet antibody detection system. These frozen aliquots were analyzed at intervals up to 23 weeks after initial freezing and storage. For analysis, the frozen platelets were thawed, washed, resuspended to 2.5 x 10(5) platelets/mL and incubated with a dilution of fresh autologous serum that lacked platelet antibody or with a similar dilution of frozen human serum containing IgG anti-PLA1 antibody. At each interval, a freshly drawn platelet sample from the same donor was incubated in the same manner and used for comparison. All platelet mixtures were then washed and incubated with fluorescein conjugated goat F (ab')2 antihuman IgG. After repeat washing, each mixture was then analyzed with a flow cytometer for the extent of fluorescent antibody bound to each platelet mixture. Anti-PLA1 antibody reactivity with either the fresh or the frozen/thawed platelets remained stable over the period of analysis, with no significant difference in immunofluorescence with either fresh or frozen platelets as target cells. Platelet recovery following the thawing step ranged from 12% to 36% and was independent of the storage time. These studies suggest that frozen platelets can be readily used as reagents for platelet antibody assays.

Antibodies↗
PubMed1988

Platelet antibody detection using frozen pooled human lymphocyte antigen-typed platelets as target cells.

The immunoreactivity of five sera containing either iso-, auto- or allo-antiplatelet antibodies to frozen-thawed human lymphocyte antigen (HLA)-typed pooled platelets was assessed to determine the practicality of using such a platelet preparation in an immunofluorescent platelet antibody system. The platelet reagent was analyzed over an 8-week period after initial freezing and storage. Mixtures of platelets with each serum or dilutions of it were initially incubated for 1 hour, then extensively washed and incubated with fluorescein-conjugated goat F(ab')2 antihuman IgG, A, M. After repeat washing, each mixture was then analyzed using a flow cytometer to determine the relative amount of fluorescent antibody bound. Not only was each of the five sera consistently positive for the presence of an anti-platelet antibody, but the extent of immunoreactivity for each remained relatively stable over the 8-week period of analysis. The results suggest that frozen pooled HLA-typed platelets should be an invaluable reagent for screening serum samples for the presence of antiplatelet antibodies in patients who are thrombocytopenic or who are refractory to platelet transfusion therapy.

Blood Platelets↗
PubMed1987

Altered villus vessel fibronectin in preeclampsia.

Fibronectin is a high molecular-weight glycoprotein found in most tissues and body fluids. Maternal plasma fibronectin levels have been shown to be elevated in preeclampsia, but little is known about placental fibronectin in preeclampsia. Fibronectin tissue distribution in placental villi was "blindly" graded by two examiners using placentas from eight nonpreeclamptic and six preeclamptic pregnancies. Selected frozen sections of normal-appearing areas from each placenta were incubated with rabbit antihuman fibronectin antiserum and then stained with fluorescein isothiocyanate-conjugated goat antirabbit immunoglobulin G and examined by fluorescent microscopy. We found less intensity of fetal vessel fibronectin staining in villi from placentas from preeclamptic pregnancies than in those of normal pregnancies (p less than 0.02, Mann-Whitney U test). It is unclear why fetal villous vessels in preeclampsia have decreased tissue fibronectin, but this may reflect an additional vascular abnormality associated with the preeclampsia syndrome.

Chorionic Villi↗
PubMed1987

Use of a bleeding time determination in the evaluation of unexplained hematuria.

Although von Willebrand's disease is an unusual cause of gross hematuria in children, it is readily treatable with fresh frozen plasma or cryoprecipitate. We present 2 cases of recurrent, painless gross hematuria owing to this congenital factor VIII deficiency disorder. In each case the diagnosis was suggested first by the finding of a prolonged bleeding time. We suggest that the bleeding time determination be included as part of the screening hemostatic studies used in the evaluation of unexplained hematuria.

Bleeding Time↗
PubMed1987

The role of apheresis in the support of life-threatening ITP relapse.

A 14-year-old girl with chronic idiopathic thrombocytopenic purpura (ITP) presented in relapse with a platelet count of 1,000/microL and a high-level serum antiplatelet IgG antibody. She previously had been unresponsive to courses of therapy with steroids, vincristine, and splenectomy. When treatment with danazol and purified immunoglobulins was unsuccessful in controlling her rapidly progressive course, an 8-day plasma exchange procedure was initiated in combination with platelet transfusion therapy and immunosuppression with cyclophosphamide and vincristine. Within 2 days, her clinical state improved markedly, correlating with a drop in her serum antiplatelet antibody level. She continued to improve and was discharged on a regimen of cyclophosphamide and danazol. Her antiplatelet antibody level had fallen to within the normal range, despite a typical platelet count of 5,000/microL during the 8-day period. Two weeks later her platelet count rose to 65,000/microL. This case suggests that a course of therapeutic plasma exchange may have a temporizing role in the acute management of life-threatening chronic ITP relapse, generating time for the more definitive therapy of immunosuppression to take effect.

Adolescent↗
PubMed1987

Mean platelet volume and platelet distribution width in the neonate.

Normal values for mean platelet volume (MPV) and platelet distribution width (PDW) have not been firmly established for term and preterm neonates. Cord blood samples from 143 healthy newborns (78 full term and 65 premature) were analyzed with the Coulter counter. Platelet count and MPV were significantly greater (p less than 0.05 and p less than 0.001, respectively) in term versus preterm infants, while PDW was significantly less in term infants (p less than 0.001). Platelet count and MPV correlated with gestational age, and platelet count also correlated with birth weight. There was a significant (p less than 0.001) negative correlation of PDW with gestational age and birth weight. These data represent normal reference ranges for neonates and demonstrate significant variation with gestational age.

Blood Platelets↗
PubMed1987

Microcytotoxicity assay for platelet antibodies using fresh and frozen fluorescein-labeled target platelets.

We describe our results with a microtoxicity assay that uses fluorescein-labeled platelets for the detection of auto-, iso-, and allo-immune platelet antibodies. The system has a number of advantages in that it is not only rapid but can accommodate multiple test specimens, requires minimal reagents, and can utilize both fresh or frozen donor platelets as the target cells. The latter attribute may allow for the development of a platelet blood banking system with more efficient platelet cross-matching capabilities.

Antibodies↗
PubMed1987

Schistocytosis, aminotransferase elevation and thrombocytopenia in preeclampsia/eclampsia.

Some preeclamptic patients have schistocytosis, abnormal liver function tests and thrombocytopenia. To determine how strongly these three abnormalities cluster with each other, a sequential series of 49 preeclamptic or eclamptic patients was analyzed for the presence of schistocytosis, serum aminotransferase elevation and thrombocytopenia. These three abnormalities were found less often together (the HELLP syndrome) than singly or in pairs. These data do not clearly separate HELLP patients from other preeclamptic patients.

Aspartate Aminotransferases↗
PubMed1986

Group-specific component (vitamin D binding protein) prevents the interaction between G-actin and profilin.

Profilin purified from human platelets formed a 1:1 molar ratio complex with rabbit skeletal muscle G-actin but was displaced by purified serum Gc (vitamin D binding protein) in a dose-dependent fashion as assessed by chromatography and ultrafiltration. This suggested that Gc and profilin competed for the same binding area on G-actin, with Gc-G-actin complexes being more stable than profilin-G-actin complexes in vitro. The binding domain for Gc on G-actin was localized to a 16,000-Da C-terminal fragment of G-actin generated by Staphylococcus aureus V8 protease, as judged by comigration on two-dimensional electrophoresis and also by overlaying electrophoresis gels with 125I-Gc. Previous studies have reported that residues 374 and 375 of G-actin are essential for binding of profilin. In this study, experiments involving tryptic removal of Cys-374 labeled with the fluorescent probe N-(iodoacetyl)-N'-(5-sulfo-1-naphthyl)-ethylenediamine showed that these C-terminal amino acids were not necessary for interaction with Gc.

Actins↗
PubMed1986

Platelet-associated IgG assay using flow cytometric analysis.

In this study we describe an immunofluorescent assay system to measure platelet-associated immunoglobulin G levels using flow cytometric analysis. This semi-quantitative system allows ready distinction of immune from non-immune related thrombocytopenias. It is simple to perform, highly reproducible and has the advantage of requiring a minimum concentration of 5000 platelets/microliter per assay sample.

Autoimmune Diseases↗
PubMed1986

Acquired von Willebrand syndrome due to an inhibitor specific for von Willebrand factor antigens.

A patient with acquired von Willebrand syndrome associated with polycythemia rubra vera is described. Her plasma factor VIII procoagulant activity (67 U/dl) and factor VIII-related antigen (117 U/dl) were normal but no von Willebrand factor activity could be detected. Factor VIII crossed immunoelectrophoresis revealed decreased levels of less anodic polymeric forms of factor VIII. Mixture of her plasma or immunoglobulin G (IgG) fraction with normal plasma resulted in complete recovery of factor VIII activity and related antigen but no measurable von Willebrand factor activity, confirming the presence of an unique inhibitor. The limited specificity of this inhibitor to antigenic sites solely on the von Willebrand portion of the factor VIII bimolecular complex is distinct from all previous reports of this syndrome. This unique inhibitor offers a molecular probe to examine the von Willebrand factor: platelet interaction.

Antigens↗
PubMed1986

Predictive value of fibronectin levels in normotensive gravid women destined to become preeclamptic.

The plasma fibronectin concentration was abnormally elevated (greater than 400 micrograms/ml) in 16 of 17 normotensive gravid women who subsequently developed preeclampsia. Of this group, 13 had elevated levels detectable greater than or equal to 4 weeks before the onset of hypertension. Our results indicate that plasma fibronectin levels can be abnormally increased long before the onset of clinical symptoms and that abnormalities of this glycoprotein may be an early indication of this pathologic process.

Blood Pressure↗
PubMed1986

Acquired dysfibrinogenemia secondary to mithramycin toxicity.

A 58-year-old black woman with IgD multiple myeloma developed a hemorrhagic diathesis within 48 hours after receiving mithramycin (20 micrograms/kg/day) for therapy of hypercalcemia. Her coagulation studies were characterized by prolonged prothrombin, partial thromboplastin, thrombin, and reptilase clotting times. Her plasma and partially purified fibrinogen were inhibitory to the clotting of normal plasma and fibrinogen. The patient's isolated fibrinogen showed a normal rate of fibrinopeptide release, but her fibrin monomer aggregation was markedly abnormal. These studies document the development of a dysfibrinogenemia secondary to mithramycin toxicity.

Afibrinogenemia↗
PubMed1986

Factor V inhibitor associated with immune complex formation.

A 72-year-old man was noted, shortly after surgery, to have a bleeding diathesis secondary to the development of a high-titer anti-factor V inhibitor. We documented the presence of factor V:anti-factor V IgG immune complexes and their disappearance following a short course of steroid therapy.

Abdomen↗