Search PubMed⌕ Search

Biomedical subjects

J M Lusher

Publications and source records attributed to J M Lusher.

At least 73 records · Page 4Linked to original sources
PubMed1991

Perspectives on the use of factor IX complex concentrates in the treatment of bleeding in persons with acquired factor VIII inhibition.

In contrast to the type of bleeding encountered in congenital hemophilia with inhibitors, the diathesis toward bleeding exhibited by patients with spontaneously acquired factor VIII (FVIII) inhibitors often is severe and life threatening. Large hematomas and retropharyngeal or central nervous system hemorrhage may appear suddenly. Thus, a high premium is placed on rapid therapeutic intervention. Several treatment options are at the physician's disposal. The role of factor IX (FIX) complex concentrates, both standard and purposely activated, is discussed. The FIX products are also known as prothrombin complex concentrates (PCCs). Prudent choice of any treatment modality requires weighing its benefits and shortcomings. Advantages of PCCs--particularly the activated products--include availability, ease of reconstitution and administration, and at least partial efficacy; control of bleeding episodes can be achieved with PCCs in many (but not all) instances. One salient disadvantage of therapy with FIX complex concentrates is that they are not subjected to such rigorous viral-attenuation processes as are most of the currently marketed FVIII products. Therefore, a small but definite risk of infection with hepatitis B or C (HBV, HCV) remains. An assay that detects antibodies against HCV has been licensed and is being used to screen blood donors. Nevertheless, up to the present time the U.S. Food and Drug Administration (FDA) has ruled that HCV screening of plasmapheresis donors should not be performed for plasma collections destined to be pooled for fractionation and that units of HCV-positive source plasma (e.g., that provided by American Red Cross donors) found to be HCV positive be sent for fractionation. The starting plasma from which FIX complex concentrates and human FVIII concentrates are made thus contains some HCV and may also contain some HBV. Because nonhemophiliacs with acquired antibodies against FVIII are unlikely to have had prior exposure to blood products and are unlikely to have been vaccinated against HBV, they are at risk of viral hepatitis and its sequelae when treated with FIX complex concentrates. Furthermore, therapy with FIX complex concentrates is not always effective in controlling bleeding in persons with FVIII inhibitors, its mechanism of action in bypassing the need for FVIII remains unclear, very large doses are required, and it has an attendant risk of several adverse effects when used in large, repeated doses. These include disseminated intravascular coagulation, thromboembolism, and acute myocardial infarction. Thus, FIX complex concentrates may play a useful role in the treatment of bleeding in nonhemophiliacs with acquired inhibitors against FVIII, but one must carefully consider their disadvantages profile.(ABSTRACT TRUNCATED AT 400 WORDS)

Autoantibodies↗
PubMed1991

The problem of therapeutic equivalence with paired qualitative data: an example from a clinical trial using haemophiliacs with an inhibitor to factor VIII.

The problem of demonstrating the equivalence of two treatments or drugs occurs fairly frequently in medicine, but is quite often misformulated. The common error is to assume equivalence is demonstrated if the usual null hypothesis of no difference is not rejected, which ignores the potential of a substantial beta-error. We describe here two procedures for testing equivalence when the data are paired and dichotomous, and provide sample size formulas. We give an example based on a clinical trial of haemophiliacs with inhibitor to Factor VIII.

Antibodies↗
PubMed1991

Hemophilia.

Explore the source record for details and available documents.

Adolescent↗
PubMed1991

Risk of human immunodeficiency virus type 1 infection among sexual and nonsexual household contacts of persons with congenital clotting disorders.

The status of human immunodeficiency virus type 1 (HIV-1) infection at the time of transmission to sexual contacts remains poorly defined. Transmission to nonsexual household contacts has appeared to be rare. A total of 505 sexual and nonsexual contacts of HIV-1-infected hemophiliacs in 349 households was observed. At entry, 10% of 201 sexual partners were anti-HIV-1-positive. Follow-up of 151 uninfected partners during a total of 351 person-years of observation showed no sero-conversions, although there were 13 pregnancies during that period. Eighty-seven percent of the seronegative respondents to a detailed questionnaire reported unprotected sexual contact at least occasionally. Among 304 other household members, including 108 parents who helped administer clotting factor concentrates to their children, none was seropositive at entry. Follow-up of 263 showed no seroconversions during a total of 605 person-years of observation. Thus, anti-HIV-1-positive hemophiliacs transmitted to their partners earlier in their course but were not found to do so when prospectively observed. No relationship to level of viremia as indicated by CD4 count, HIV-1 p24 antigenemia, or acquired immunodeficiency syndrome was found. Anti-HIV-1-positive hemophiliacs had not transmitted to their nonsexual household contacts before study entry and did not do so subsequently, indicating that the risk from even close nonsexual contact is extremely low.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Retrovir therapy in hemophilic children with symptomatic human immunodeficiency virus infection: efficacy and toxicity.

In desperation, we have used retrovir in five hemophilic children (10-16 years old) over the past 22 months. All had presented with various clinical manifestations of acquired-immune-deficiency-syndrome (AIDS)-related complex or AIDS. Our decision to treat with retrovir was based on clinical manifestations and very low numbers of CD4 cells (less than 200). The most common clinical presentation was recurrent oral moniliasis. Other significant findings included recurrent herpes zoster, thrombocytopenia, growth failure, and biliary tract infection. Initially, all five children received the full adult dosage of retrovir (200 mg q 4 h x 6 doses/day). This dosage had to be reduced in four children because of toxicity. The most commonly observed toxic side effects were anemia and neutropenia. Alanine aminotransferase (ALT) levels rose to 4-10 times the upper limit of normal in four of five children. One was on concomitant ketokonazole prior to the rise in ALT level. Myalgia and headache were reported by two patients. Improvement in clinical and immunological status was observed in all children initially. After 12-18 months of retrovir therapy, infectious complications secondary to prolonged neutropenia were seen in these immunocompromized children. However, compared to historic controls, these children have had fairly stable disease. We feel that all hemophilic children with symptomatic human immunodeficiency virus infection should be offered this drug, even though the optimal dosage for children is not yet established.

AIDS-Related Complex↗
PubMed1990

Transmission of human immunodeficiency virus type 1 by dry-heated clotting factor concentrates. Transfusion Safety Study Group.

The Transfusion Safety Study monitored susceptible persons for human immunodeficiency virus type 1 (HIV-1) infections transmitted by plasma products and blood components. Through December, 1988, 6 subjects without antibody to HIV-1 (anti-HIV-1) became seropositive after receiving dry-heated factor VIII concentrate. The preparations implicated in 3 cases were derived entirely from anti-HIV-1-screened donors. In all instances, HIV-1 infection could be explained by concentrates heated at 60 degrees C for 24-30 h. Limiting consideration to concentrates and components administered after study entry showed that 4 of the seroconversions occurred among 122 subjects given 10 million units of factor VIII concentrates. No seroconversions occurred among 84 subjects given 5 million units of factor IX concentrates, or 83 who received components from over 26,000 unpaid donations. Serologic surveillance of anti-HIV-1-negative subjects provides important information, and should be routine in the management of persons receiving clotting factor concentrates.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Viral safety and inhibitor development associated with factor VIIIC ultra-purified from plasma in hemophiliacs previously unexposed to factor VIIIC concentrates. The Monoclate Study Group.

A multicenter study evaluated the potential for transmitting non-A/non-B hepatitis, as well as other viruses, with the use of the factor VIIIC product Monoclate. This product is purified from plasma via the monoclonal process that includes heat treatment for ultra-purification as a final step. Twenty different lots of Monoclate were used, and each patient received the assigned lot for the first 6 months of the trial. Nineteen of 38 patients adhered strictly to International Committee on Thrombosis and Hemostasis criteria in that they had normal liver enzymes, no evidence of hepatitis prestudy, and had no previous blood product use. Fourteen hemophilia centers from the United States, the United Kingdom, the Netherlands, and Israel participated in this study. Development of factor VIII inhibitor occurred in six of 38 patients, which was within the statistically expected range. Adverse events were mild, and Monoclate was well tolerated in this group. All 38 patients remained HIV seronegative.

Alanine Transaminase↗
PubMed1990

Initial clinical experience with a new pasteurized monoclonal antibody purified factor VIIIC.

Heat treatment of lyophilized factor VIII and factor IX concentrates has been found to eliminate HIV virus infectivity in plasma-derived products. Pasteurization of factor VIII in solution has recently been used to reduce the risk of hepatitis transmission in concentrates prepared by standard fractionation methods. This report presents early experience with factor VIIIC prepared by monoclonal antibody immunoaffinity chromatography following pasteurization of the factor VIIIC/von Willebrand factor complex (Monoclate-P). Twelve patients were treated in three centers with Monoclate-P. Recovery and survival of factor VIII clotting activity were determined and patients were closely monitored for infusion safety. The mean half-life was 14.2 +/- 5.0 while recovery in predicted plasma volume was 72 +/- 12% corresponding to a response of 1.99 +/- 0.66 U/dL for every U/kg administered. These values are very similar to those found for Monoclate in previous studies indicating that pasteurized factor VIIIC purified by immunoaffinity chromatography retains satisfactory pharmacokinetic properties with an added margin of viral safety.

Adolescent↗
PubMed1989

The use of purified clotting factor concentrates in hemophilia. Influence of viral safety, cost, and supply on therapy.

Treatment of hemophilia, although greatly improved in recent years, continues to be problematic owing to infectious complications of blood product replacement therapy. This report examines the therapeutic options presently available for the treatment of hemophilia, focusing on the potential for repeated viral exposure to influence the progression of infectious disease, decreased risks of viral transmission with blood products produced using newer viral inactivation procedures, higher economic costs of newer blood products, and the current inadequate supply of blood products in the United States.

Acquired Immunodeficiency Syndrome↗
PubMed1989

The use of porcine factor VIII concentrate (Hyate:C) in the treatment of patients with inhibitor antibodies to factor VIII. A multicenter US experience.

The response to a highly purified concentrate of porcine factor VIII was evaluated in 45 bleeding episodes in 38 patients with high responding inhibitor antibodies to factor VIII. A total of 437 infusions were given. The patients came from 25 hemophilia centers in the United States. The majority had a life- or limb-threatening hemorrhage for which other modalities had not been successful. In 32 of 45 episodes, a good to excellent response was obtained. Adverse reactions were minimal, occurring in 17 treatment episodes, and were mostly treated with antihistamines and/or hydrocortisone. No clear predictor of clinical response to porcine factor VIII concentrate was identified, including pretreatment human and porcine inhibitor levels, percentage of cross-reactivity between the human and porcine antibodies, and the presence of measurable levels of factor VIII after the porcine factor concentrate was given. Anamnesis to porcine factor VIII did occur in some instances. Porcine factor VIII is a valuable modality in the treatment of serious hemorrhages in patients with inhibitors to factor VIII. Its use should be considered early in the course of severe hemorrhage in these patients.

Adolescent↗
PubMed1987

Use of intravenous gamma globulin in children and adolescents with idiopathic thrombocytopenic purpura and other immune thrombocytopenias.

Approximately 85 to 90 percent of cases of idiopathic thrombocytopenic purpura (ITP) in children are of the acute, self-limited variety that generally occurs after a viral infection. The remaining 10 to 15 percent of children with this disorder have the chronic (autoimmune) type of ITP. For these patients, splenectomy is often the recommended treatment if severe bleeding occurs and platelet counts remain below 40,000/mm3. However, splenectomy has associated risks and the response to this surgery cannot always be predicted. Intravenous gamma globulin (IVIG) has proven useful as an alternative to splenectomy, especially in children who are considered too young for splenectomy or in those in whom there is no response to splenectomy. It should be noted that booster shots are frequently required and the patient's ITP may become refractory. IVIG may also be useful in preparing a child with ITP for splenectomy and in treating children or adolescents with ITP who have central nervous system or other serious hemorrhages. Although IVIG is not always effective in raising the platelet count, it does provide a very useful alternative method of treating this disorder.

Adolescent↗
PubMed1987

Management of patients with factor VIII inhibitors.

In summary, while a great deal of information has accumulated concerning the properties and natural history of F VIII inhibitors, management remains frustrating and controversial. While bleeding episodes in those who are low responders can be treated with F VIII concentrates, treatment of bleeding in high responders is often much more difficult. Current therapeutic options include F VIII concentrates of human or porcine origin in high dosage, and PCC or APCC. The choice of treatment depends on the patient's current inhibitor concentration, the type and severity of bleeding, product availability, and the preference of the medical personnel involved. However, none of the available therapeutic modalities work as well as F VIII in a hemophiliac without an inhibitor. Perhaps more promising are the immune tolerance regimens that have been developed and are now being modified and fine tuned by a number of investigators. Such regimens have reportedly eradicated F VIII inhibitors in some hemophiliacs, and have converted others from high responders to low responders, in whom bleeding episodes can be effectively treated with conventional doses of F VIII. In contrast to the F VIII inhibitors developing in hemophiliacs, those developing in nonhemophiliacs can often be eradicated with corticosteroids or immunosuppressive drugs, either alone or in combination with F VIII. Not all respond to such approaches and serious hemorrhage may still occur. Treatment of bleeding episodes has included the use of human or porcine F VIII, APCC and, in two instances, DDAVP.

Animals↗