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Biomedical subjects

J O Ballard

Publications and source records attributed to J O Ballard.

At least 19 recordsLinked to original sources
PubMed2005

Knee and hip arthroplasty infection rates in persons with haemophilia: a 27 year single center experience during the HIV epidemic.

Total joint replacement (TJR) is an option for the management of chronic haemophilic arthropathy. Because surgery is technically challenging, there is a high rate of deep prosthetic infections, particularly in human immunodeficiency virus (HIV)-infected individuals. We determined the incidence of deep infection rates following total knee and hip arthroplasties in HIV-seropositive and HIV-seronegative persons with haemophilia. Fifty-one primary joint replacements were performed on 32 patients seen at a regional comprehensive haemophilia care center from 1975 to 2002. Thirty prostheses were placed in patients who were HIV-seropositive prior to surgery (n = 14) or seroconverted later (n = 16). Median age at the time of surgery was 33 years (range: 20-61) among 19 HIV-seropositive patients and 35 years (range: 26-74) among 13 HIV-negative patients. Median duration of follow-up was 83 months (range: 2-323). Rate of primary joint infection per artificial joint-year by HIV status was compared by Poisson regression. Main outcome measures were the incidence of primary replacement joint infections by HIV status. Deep infections developed in five (9.8%) of 51 replacement joints. There were two infections during 204.15 joint-years without HIV infection and three infections during 205.28 joint-years with HIV infection. The incidence rate of joint infection (0.98 vs. 1.46 per 100 joint-years) was not increased with HIV (relative risk, RR: 1.49, 95% CI: 0.25-8.93, P = 0.66). We conclude that HIV infection is not a contraindication to knee or hip replacement arthroplasty in the appropriate clinical setting.

Adult↗
PubMed1990

Evaluation of the safety, recovery, half-life, and clinical efficacy of antithrombin III (human) in patients with hereditary antithrombin III deficiency. Cooperative Study Group.

Antithrombin III (Human) (AT III) was administered to 18 patients with documented hereditary AT III deficiency. In eight patients with no ongoing clinical symptoms of thrombosis, the percent increase per unit AT III infused per kilogram of body weight ranged from 1.56% to 2.74%, and the half-life from 43.3 to 77.0 hours. No significant difference was noted between patients receiving and those not receiving coumarin therapy. In clinically ill patients, the in vivo recovery was significantly lower and ranged from 0.64% to 1.90% increase per unit AT III infused/kg. Efficacy of AT III was evaluated in 13 patients for the prevention or treatment of thrombosis. AT III was efficacious as assessed by the absence of thrombotic complications after surgery and/or parturition, and the nonextension and nonrecurrence of thrombosis in patients exhibiting an acute thrombotic episode. No side effects were noted. Follow-up studies indicated no hepatitis B seroconversion and no alanine aminotransferase elevations in patients who were not transfused with other blood products.

Adult↗
PubMed1989

Predictive markers for the acquired immunodeficiency syndrome (AIDS) in hemophiliacs: persistence of p24 antigen and low T4 cell count.

STUDY OBJECTIVE: To investigate the predictive value of assays for human immunodeficiency virus (HIV) p24 antigen, p24 antibody, and gp120 antibody compared with T4 cell counts. DESIGN: Prospective cohort selected from persons who had HIV-antibody seroconversion. PATIENTS: Eighty-seven persons with hemophilia with an actuarial cumulative acquired immunodeficiency syndrome (AIDS) incidence of 26% (CI, 12% to 40%), 8 years after HIV-antibody seroconversion. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Human immunodeficiency virus p24 antigen was detected in 8 of 74 (11%) of the patients without AIDS and 7 of 13 (54%) of the patients with AIDS. The 2-year actuarial incidence of AIDS was 24% (CI, 0% to 48%) after detection of p24 antigen, 16% (CI, 0% to 34%) after loss of p24 antibody, 20% (CI, 0% to 45%) after loss of gp120 antibody, 31% (CI, 15% to 47%) after a T4 count of less than 200 cells/microL, and 67% (CI, 31% to 100%) after a T4 count of less than 200 cells/microL among those patients positive for p24 antigen. Very low numbers of T4 and T8 lymphocytes, presence of p24 antigen in serum, and absence of p24 antibody all had some predictive value. However, only p24 antigen (relative hazard 6.0, P = 0.008) and T4 counts (relative hazard 5.3, P = 0.002 with T4 count less than 200 cells/microL) independently predicted AIDS up to 12 months before diagnosis. CONCLUSIONS: Strong predictors of AIDS are p24 antigenemia or low T4 counts. Detection of p24 antigen is highly specific and complementary to the greater sensitivity of low T4 counts. These findings have important implications regarding prognosis, counseling, and the planning of clinical trials.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Impaired hemostasis caused by beta-lactam antibiotics.

Beta-lactam antibiotics can directly impair hemostasis by two separate nonimmune mechanisms. First, the NMTT-substituted cephalosporin drugs may cause hypoprothrombinemia by interfering with the hepatic activation of clotting factors II, VII, IX, and X. Second, the antipseudomonal penicillins may cause the bleeding time to be prolonged by interfering with platelet aggregation to physiologic agonists. In surgical patients who are malnourished, have impaired gastrointestinal function, or have renal failure, the potential for these adverse effects is increased. Serious bleeding requires treatment with fresh frozen plasma when hypoprothrombinemia is caused by NMTT-containing cephalosporins, since the prothrombin time returns to baseline relatively slowly after therapy with vitamin K. Hemorrhage caused by beta-lactam-induced platelet dysfunction must be treated with platelet concentrates, since new platelets sufficient to correct the defect do not enter the circulation for several days after treatment with the offending drug is discontinued. The more desirable approach is to prevent hypoprothrombinemia by giving vitamin K prophylaxis and to avoid beta-lactams that impair platelet function in seriously ill patients at increased risk for bleeding.

Anti-Bacterial Agents↗
PubMed1988

Primary pulmonary hypertension in patients with classic hemophilia.

Five patients with classic hemophilia were found to have primary pulmonary hypertension, a disorder not previously recognized in this population. All patients had had their coagulation disorder treated for 10 years or more with self-administered lyophilized concentrates of factor VIII, and all had antibodies to human immunodeficiency virus (HIV). Primary pulmonary hypertension was confirmed by histologic means at autopsy in one patient and by lung biopsy findings in another. In the other three patients, the findings are in agreement with this diagnosis. No patient had underlying cardiac or pulmonary disease, or clinical or pathologic evidence of collagen-vascular disease, vasculitis, parasitic disorders, hemoglobinopathy, or exposure to anorexigenic agents. Whether the primary pulmonary hypertension was related to treatment with lyophilized factor VIII, or to the presence of antibodies to HIV, or both, is unknown.

Adult↗
PubMed1987

Natural history of human immunodeficiency virus infections in hemophiliacs: effects of T-cell subsets, platelet counts, and age.

Serial T-cell subsets and platelet counts were determined in a cohort of 84 hemophiliacs in whom time of seroconversion for human immunodeficiency virus (HIV) antibody could be ascertained. An abrupt decrease in the number of T-helper (T4) cells was seen in 9 patients 12 to 24 months before the acquired immunodeficiency syndrome (AIDS) was diagnosed (p = 0.0007 compared with those who did not develop AIDS). Thrombocytopenia also was associated with an increased risk for AIDS (p = 0.02), as was older age at the time of seroconversion (p = 0.03). Ten patients developed AIDS at 24 to 95 months after seroconversion, for a cumulative incidence (+/- SE) of 18.0% +/- 7.1% at 6 years. Hemophiliacs who had T4 cell counts of less than 200 cells/microL had a 50% +/- 16% cumulative incidence of AIDS within 2 years, indicating that decreasing or very low T4 cell counts have predictive value for the development of AIDS. Furthermore, the data suggest that thrombocytopenia and older age may be markers for a cofactor that increases the risk for AIDS in hemophiliacs.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Vitamin K antagonism of coumarin intoxication in the rat.

An in vitro system which expresses all enzyme activities related to vitamin K-dependent carboxylation of blood clotting factors was prepared from livers of rats overdosed with warfarin, difenacoum and dicumarol respectively. In this system, the activities of the two pathways that are known to produce active reduced vitamin K1 cofactor for the carboxylation reaction were measured. Also the ability of high concentrations of vitamin K1 to overcome inhibition of clotting factor synthesis was studied. In the systems prepared from livers of warfarin and difenacoum intoxicated rats, pathway I was inactive. Vitamin K epoxide reductase was also inactive which strongly suggests that this enzyme catalyzes the activity of pathway I in vivo. Reduction of vitamin K1 by pathway II bypassed the inactive pathway I and resulted in carboxylation activity. This pathway therefore mediates the antidotic effect of vitamin K1 in the coumarin intoxicated liver. In the in vitro system prepared from dicumarol intoxicated livers the activity of pathway I was not significantly affected. Dicumarol however was a strong inhibitor when added to liver microsomes in vitro.

4-Hydroxycoumarins↗
PubMed1986

Further studies on ultrasonic properties of blood clots.

Two-dimensional echocardiography has been found to be an effective clinical tool in diagnosing intracardiac thrombi. Misdiagnosis may, however, still frequently occur because of the difficulty in differentiating the thrombi from other intracavitary masses based only on the echographic appearance of these structures. Ultrasonic tissue characterization techniques have been used in attempts to minimize this diagnostic uncertainty. Previously, we have shown that all ultrasonic parameters of blood, including ultrasonic backscatter, a quantitative measure of echogenicity, at 7.5 MHz increase rapidly following clotting. In this article, we report recent results on the measurements of attenuation and backscatter of thrombi as a function of time following clotting over the frequency range of 3 MHz to 8 MHz. These results indicate that ultrasonic backscatter from thrombi 12 h old is at least 18 dB higher than that of unclotted blood over the frequency range of 3 MHz to 8 MHz, and the slope of the attenuation coefficient is increased to 0.43 dB/cm-MHz. Comparison with the backscatter of bovine myocardium shows that the myocardium is more echogenic than fresh thrombi and is less echogenic than thrombi 12 to 24 h old. Similar results were also obtained for integrated backscatter measurements over the same frequency range.

Animals↗
PubMed1986

Potential for bleeding with the new beta-lactam antibiotics.

Several new beta-lactam antibiotics impair normal hemostasis. Hypoprothrombinemia has occurred frequently with cephalosporins that possess a methylthiotetrazole substitution (cefamandole, moxalactam, and cefoperazone). The incidence ranges from 4% to 68%, and the risk is greatest in debilitated patients with cancer, intra-abdominal infection, or renal failure. Impaired platelet function caused by perturbation of agonist receptors on the platelet surface has occurred primarily with beta-lactam antibiotics having an alpha-carboxyl substitution (moxalactam, carbenicillin, and ticarcillin). These antibiotics often cause the template bleeding time to be markedly prolonged (greater than 20 minutes). Acylureidopenicillins, which lack the alpha-carboxyl marker, impair platelet function less frequently and only modestly prolong the bleeding time. If serious hemorrhage occurs, hypoprothrombinemia associated with methylthiotetrazole-substituted cephalosporins should be treated with fresh frozen plasma. Likewise, dangerous bleeding due to impaired platelet aggregation requires treatment with platelet concentrates.

Anti-Bacterial Agents↗
PubMed1985

Changes in plasma haptoglobin and alpha-2-macroglobulin in hemophiliacs receiving factor replacement therapy.

Plasma proteins were studied in 84 patients with hemophilia A, who were receiving factor replacement therapy. Compared with age-matched controls, 63 patients (75%) had subnormal haptoglobin and 58 (69%) had elevated alpha-2-macroglobulin. Causes for depressed haptoglobin were sought by correlating ABO blood types, liver function tests, factor VIII procoagulant levels, and intensity of yearly exposure to clotting factor products. Subnormal haptoglobin levels in chronically transfused patients may relate in part to hemolysis from AB incompatability. However, depressed haptoglobin levels were also found in group O hemophiliacs without other evidence of hemolysis. Most patients lacked evidence of active liver disease, making synthetic deficiency unlikely. There was close correlation between depressed haptoglobin and severity of clotting factor deficiency. The degree of alpha-2-macroglobulin elevation correlated with severity of procoagulant deficiency but not with intensity of clotting factor replacement therapy. Since alpha-2-macroglobulin plays a major role in the catabolism of fibrinogen, elevated levels may represent a compensatory increase in response to exogenous fibrinogen contained in the clotting factor concentrates. Alternatively, since alpha-2-macroglobulin has potent immunosuppressive properties, the elevation may represent a response to transfused alloantigens. Whatever the underlying cause, it is likely the elevations are due to endogenous production rather than to transfusions since clotting factor concentrates contain minimal amounts of alpha-2-macroglobulin.

ABO Blood-Group System↗
PubMed1984

Erythroleukemic infiltration of a lymph node: use of hemoglobin immunohistochemical techniques in diagnosis.

Isolated submandibular adenopathy developed in a patient who had subacute erythroleukemia. Lymph node biopsy revealed a proliferation of immature cells and scattered foci of dyserythropoietic normoblasts. Since a review of the literature revealed no detailed description of an erythroleukemic lymph node infiltrate, a histopathologic study of this node was undertaken. The immature cells were identified as erythroblasts and pronormoblasts by histochemical staining (periodic acid-Schiff reagent and chloroacetate esterase), immunohistochemical reaction (directed against hemoglobin), and electron microscopy. The diagnosis of erythroleukemic lymph node infiltrate may be missed in the absence of a high index of suspicion. It is concluded that the detection of hemoglobin within malignant cells is most helpful in establishing the diagnosis.

Bone Marrow↗
PubMed1984

Comparison of the effects of mezlocillin, carbenicillin, and placebo on normal hemostasis.

Mezlocillin was compared with carbenicillin and 0.9% NaCl as placebo in a double-blind manner to determine its effect in vivo on hemostasis in normal volunteers. Eighteen subjects were randomized to receive mezlocillin, 4 g every 6 h; carbenicillin, 7.5 g every 6 h; or placebo, 50 ml every 6 h, each given for 20 intravenous doses unless the template bleeding time after 10 doses was greater than 15 min. Template bleeding times were determined before the dose 1 and 1 h after doses 10 and 20. Five of six (83%) subjects receiving carbenicillin developed template bleeding time prolongation to greater than 21 min, and two of six (33%) subjects receiving mezlocillin and one of six (17%) subjects receiving carbenicillin had mild template bleeding time prolongations of less than 13 min. Coagulation studies (prothrombin time, partial thromboplastin time, and thrombin time) were normal in all subjects, and blood salicylate levels were negative. Thus, in standard therapeutic doses, mezlocillin was less likely than carbenicillin to prolong the template bleeding time above normal (P = 0.04) and, when prolongation occurred with mezlocillin, it was mild. These data support the selective use of mezlocillin in patients at increased risk for bleeding and who require therapy with an antipseudomonal penicillin.

Adult↗
PubMed1984

Perirectal infections in acute leukemia. Improved survival after incision and debridement.

During a 6-year period, 16 (7.9%) of 202 patients with acute leukemia of both the lymphocytic and nonlymphocytic types developed perirectal infections. All patients were febrile and severely neutropenic (14 patients had absolute neutrophil counts of less than 100/mm3). Lesions were painful and indurated but lacked fluctuance. Urinary retention, peritoneal signs, and extension of the infection to the genitalia were common. Eleven patients had bacteremia, and an average of 2.1 enteric bacteria were recovered from samples of abscess fluid or blood. Perirectal lesions were operatively incised and debrided (10 patients), unless spontaneous drainage occurred (5 patients). These 15 patients became pain-free in less than 48 hours and afebrile in 2 to 8 days. Drained lesions healed in all. Thirteen of fifteen patients left the hospital, whereas 2 died in the hospital of unrelated causes. The only patient whose lesion was not drained died of continuous bacteremia. Early incision and debridement contributed to our patients' improved survival.

Acute Disease↗
PubMed1983

Moxalactam. Evaluation of clinical bleeding in patients with abdominal infection.

Previous clinical studies have emphasized that hypoprothrombinemia may occur during treatment with moxalactam disodium, a new broad-spectrum cephalosporin. Usually, this abnormality is corrected by administering vitamin K. Recent case reports have described bleeding complications associated with moxalactam therapy and suggested that platelet function is depressed by this drug. We studied eight patients with abdominal infection who were treated with moxalactam. Six of them had prolonged template bleeding times, and two had clinically significant hemorrhage (epistaxis, hematuria, and rectal bleeding) during treatment with moxalactam. These observations suggest that coagulation studies and template bleeding times should be monitored during moxalactam therapy, especially before major surgery.

Abdomen↗
PubMed1983

Amrinone-mediated thrombocytopenia.

Amrinone, a new cardioactive drug, was administered for, on average, 27.9 d to 12 patients in severe congestive heart failure. Thrombocytopenia occurred in 4 patients, while a progressive decline in platelet numbers developed in 3 additional patients. The mechanism for these adverse effects of amrinone is unclear, but merits further study because of its frequency.

Aminopyridines↗