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Biomedical subjects

R Hong

Publications and source records attributed to R Hong.

At least 73 records · Page 4Linked to original sources
PubMed1989

Prediction of persistent immunodeficiency in the DiGeorge anomaly.

To assess the natural history of the immune defect in DiGeorge anomaly, we reviewed serial immunologic studies in 18 patients. The diagnosis was made with criteria based on the concept of the DiGeorge anomaly as a field defect. Initial or early follow-up laboratory examination suggested moderate to normal T cell function in 14 patients. None of these patients have lost T cell capability; they have never had infections characteristic of T cell deficiency. Four patients had clinical and laboratory evidence of profound immunodeficiency. A decreased number of CD4+ cells (less than 400/microliters) and a decrease in phytohemagglutinin responsiveness (stimulation index less than 10) may be useful in discriminating patients with immunodeficiency; absolute lymphocyte count and immunoglobulin values were not informative. At the time of surgery, the thymus was not found in 11 of 14 patients; however, only two of these patients had immunodeficiency. Patients with a persistently low number of CD4+ cells and decreased phytohemagglutinin response are candidates for immunologic reconstitution.

Aging↗
PubMed1989

Prognostic significance of programmed ventricular stimulation in survivors of acute myocardial infarction.

The prognostic significance of the response to programmed ventricular stimulation was studied in 75 stable survivors of acute myocardial infarction. Programmed ventricular stimulation induced sustained ventricular arrhythmias in 33 (44%) patients and did not induce these arrhythmias in 42 (56%) patients. During a mean follow up of 18 months, four patients died suddenly and three developed spontaneous sustained ventricular tachycardia. The occurrence of arrhythmic events was not significantly different in patients with inducible sustained arrhythmias and those without, but such events were predicted by the presence of mild congestive heart failure. Although the inducibility of sustained ventricular tachycardia (but not ventricular fibrillation) seemed to identify a high risk subset with an arrhythmic event rate of 21% compared with 5.5% in others, it had a low sensitivity (57%) and a low positive predictive accuracy (21%) for arrhythmic events. Programmed ventricular stimulation is not helpful in identifying a subset of patients at high risk after an uncomplicated acute myocardial infarction.

Arrhythmias, Cardiac↗
PubMed1989

Phase 1 clinical trial of recombinant interleukin-2: a comparison of bolus and continuous intravenous infusion.

The toxicologic, biologic, and clinical effects of recombinant interleukin-2 (IL-2) were tested in 25 patients with cancer. Escalating doses from 10(3) to 10(7) U/m2 per day were given by either daily bolus injection (BI) or continuous infusion (CI) for 7 consecutive days. Dose-limiting toxicities included a decline in performance status, systolic hypotension, and fever, which reversed promptly with discontinuation of therapy. The maximum tolerated dose of IL-2 by BI for 7 days was 3 X 10(6) U/m2 per day and for CI was 10(6) U/m2 per day. Significant changes in the number, phenotype, and function of circulating peripheral blood lymphocytes occurred at doses greater than or equal to 10(6) U/m2 per day by both administration schedules. With the initiation of therapy, a decline in the number of circulating peripheral blood lymphocytes (PBL) was seen in patients treated by either BI or CI. Additionally, the in vitro cytotoxic activity of these PBL against K562 was markedly decreased. Within 24 h of completing BI or CI, a rebound increase in the number of circulating PBL was seen. The phenotype of the circulating PBL after completion of treatment showed a significant (p greater than or equal to 0.05) increase in the numbers of OKT-3+, OKT-8+, OKT-10+, OK-Ia+, OKM1+, and OKT-11+ for patients treated by CI. Those patients treated by BI had a significant increase in Ia+ and OKT10+ cells. At IL-2 doses greater than or equal to 10(5) U/m2 per day, the PBL obtained following treatment with rIL-2 demonstrated in vitro cytotoxic capacity against K562 target cells that was significantly enhanced over pretreatment levels. This study demonstrates that IL-2 can be given by CI or BI in a non-ICU setting with acceptable dose-dependent toxicity. Upon completion of treatment an increase in the number of activated cells could be detected. Although no clinical responses occurred, the generation of endogenous activated PBL capable of enhanced cytotoxicity is encouraging. Future studies will explore the use of multiple courses of treatment with IL-2 to determine if therapeutic efficacy can be accomplished.

Antibodies, Monoclonal↗
PubMed1988

Contaminant bands on SDS-polyacrylamide gel electrophoresis are recognised by antibodies in normal human serum and saliva.

Contamination of sodium dodecyl sulphate-polyacrylamide gel electrophoresis samples has commonly produced artefactual bands when sensitive detection systems, such as silver staining or immunoblotting procedures, have been used. Evidence suggests that these bands originate from human skin contamination of reagents and equipment. The presence of antibodies to contaminating bands, in serum and saliva samples from normal donors, detected in immunoblotting experiments, is described; the isotype distribution of these naturally occurring antibodies has also been investigated.

Antibodies↗
PubMed1988

Electrophysiologic effects of intravenous magnesium in patients with normal conduction systems and no clinical evidence of significant cardiac disease.

Parenteral magnesium has been used for several decades in the empiric treatment of various arrhythmias, but the data on its electrophysiologic effects in man are limited. We evaluated the electrophysiologic effects of magnesium sulfate (MgSO4) administration in eight normomagnesemic patients with normal mononuclear cell magnesium content, who had no clinically significant heart disease and had normal baseline electrophysiologic properties. After administration of intravenous MgSO4, serum magnesium rose significantly from 1.9 +/- 0.1 to 4.4 +/- 1.7 mg/dl (p less than 0.02). During a maintenance magnesium infusion, we observed significant prolongation of the ECG PR interval (145 +/- 18 to 155 +/- 26 msec, p less than 0.05), AH interval (77 +/- 27 to 83 +/- 26 msec, p less than 0.002), antegrade atrioventricular (AV) nodal effective refractory period (278 +/- 67 to 293 +/- 67 msec, p less than 0.05), and sinoatrial conduction time (60 +/- 34 to 76 +/- 32 msec, p less than 0.02). No significant effect was observed on sinus cycle length, sinus node recovery time, intra-atrial or intraventricular conduction times, QRS duration (during both sinus rhythm and ventricular pacing), QT interval, HV interval, paced cycle length resulting in AV nodal Wenckebach block, AV nodal functional refractory period, retrograde ventriculoatrial (VA) effective refractory period, or atrial and ventricular refractory periods. These findings, in conjunction with the demonstrated ability of magnesium to block slow channels for sodium movement, may provide an explanation of the mechanism by which magnesium exerts its effect in the treatment of atrial and junctional arrhythmias.

Adult↗
PubMed1988

The in vitro function of lymphocytes from 25 cancer patients receiving four to seven consecutive days of recombinant IL-2.

Twenty-five cancer patients received human recombinant interleukin-2 (IL-2) for 4 to 7 consecutive days in a Phase I trial. IL-2 was administered either as a daily intravenous bolus infusion (lasting 15 min), or as a continuous infusion lasting 24 h each day. Prior studies have demonstrated that in vivo administration of IL-2 at high doses is associated with changes in the phenotype of circulating peripheral blood lymphocytes (PBL) (determined with monoclonal antibodies), and the induction of augmented in vitro natural killer activity (NK) by PBL obtained following in vivo IL-2. We have noted that fresh lymphocytes obtained after 4-7 consecutive days of IL-2 (greater than or equal to 10(6) U/m2/day) show an augmented ability to kill NK-sensitive and -insensitive target cells (K562 and Daudi targets, respectively), especially when tested with IL-2 present during the 4-h 51Cr release assay. We have further analyzed lymphocytes in a battery of in vitro proliferative and cytotoxic assays. We present here the summary of this quantitative analysis of their responses in both antigen-specific and -nonspecific immune responses. Striking in vitro changes were observed in the proliferative response to IL-2 and in cytotoxicity stimulated by (or requiring) in vitro IL-2. Proliferative responses to antigens and to mitogens were not as dramatically altered following in vivo IL-2, nor were allospecific or allo-activated cytotoxic interactions. These studies indicate that the most striking changes in lymphocyte function measured in vitro following in vivo IL-2 are seen in those functions requiring IL-2.

Cytotoxicity, Immunologic↗
PubMed1988

Out-of-hospital cardiac arrest in patients with no overt heart disease: electrophysiologic observations and clinical outcome.

Electrophysiologic studies were performed in nine survivors of out-of-hospital cardiac arrest who had no overt heart disease on clinical, hemodynamic and angiographic evaluation. Cardiac arrest occurred during sedentary activity in seven patients and during exercise in two; no patient was on antiarrhythmic drugs at the time of cardiac arrest. Twenty-four hour ambulatory electrocardiographic monitoring demonstrated premature ventricular beats in four patients (44%). Electrophysiologic stimulation induced sustained ventricular tachycardia (VT) or fibrillation (VF) in five patients, nonsustained VT in one patient and less than five ventricular beats in the remaining three patients. Of five patients with inducible sustained VT or VF, four had complete suppression of inducible VT with antiarrhythmic therapy, and none of these four patients died suddenly or had clinical VT after an average follow-up of 27 months (range 12 to 41 months). The remaining patient with inducible sustained VT refused serial electropharmacologic testing, was treated empirically with amiodarone (400 mg/day) and died suddenly eight months later. Of the four patients with noninducible sustained VT or VF, three received no antiarrhythmic therapy and one was given a beta-blocker. None had recurrent cardiac arrest or symptomatic VT after an average follow-up of 17 months (range 13 to 20 months). Thus, inducibility of sustained VT or VF provided a reliable end point for long term antiarrhythmic therapy and noninducibility identified a subset of patients that had an excellent prognosis without specific antiarrhythmic therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Reconstitution of T- and B-cell function after T-lymphocyte-depleted haploidentical bone marrow transplantation in severe combined immunodeficiency due to adenosine deaminase deficiency.

A 4-month-old male received a T-lymphocyte-depleted haploidentical bone marrow transplant (BMT) for correction of severe combined immunodeficiency (SCID) due to adenosine deaminase (ADA) deficiency. Although previous haploidentical bone marrow transplants have been attempted in ADA-deficient SCID, complete reconstitution of both B-lymphocyte and T-lymphocyte function has not been obtained after a single transplant. In this patient, however, rapid, complete, and persistent engraftment occurred. Potential reasons for this successful reconstitution include the use of ablation by chemotherapy (busulfan, cyclophosphamide, and cytosine arabinoside), the in vitro technique of using monoclonal antibody (CT-2) and complement to deplete the donor cells of T lymphocytes, and the relative good health of the patient prior to the transplant. Further trials using this method of haploidentical BMT may prove it to be a successful method of immunologic reconstitution in ADA-deficient SCID patients for whom an HLA-identical marrow is not available.

Adenosine Deaminase↗
PubMed1987

Early tolerance to hemodynamic effects of high dose transdermal nitroglycerin in responders with severe chronic heart failure.

Transdermal systems for delivery of nitroglycerin have been shown to provide sustained blood levels of the drug for at least 24 hours. Investigations of hemodynamic effects of transdermal nitroglycerin in patients with heart failure have demonstrated a transient reduction in pressure lasting less than the expected 24 hours. These findings could be due to the development of circulatory tolerance to the vasodilatory effects of nitroglycerin or to insufficient drug dosing. In the present study, we compared the hemodynamic effects of the first and the second doses of high dose (120 mg) transdermal nitroglycerin given 24 hours apart in 11 responders (greater than or equal to 20% reduction in mean pulmonary artery wedge pressure lasting greater than or equal to 2 hours). Initiation of nitroglycerin therapy resulted in a significant reduction in mean right atrial pressure lasting for 14 hours and in a reduction in mean pulmonary artery and mean pulmonary artery wedge pressures lasting 24 hours. After administration of the second dose, mean right atrial pressure at 2 hours (9 +/- 5 versus 7 +/- 4 mm Hg), 4 hours (8 +/- 5 versus 6 +/- 4 mm Hg) and 8 hours (8 +/- 5 versus 6 +/- 3 mm Hg) was higher than after the first dose (p less than 0.05). Both mean pulmonary artery and mean pulmonary artery wedge pressures were significantly higher after the second nitroglycerin dose.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Cutaneous↗
PubMed1987

Immunologic studies of lymph node lymphocytes in the generalized lymphadenopathy syndrome.

A generalized lymphadenopathy syndrome (GLS) occurs in persons at high risk for development of acquired immunodeficiency syndrome (AIDS). The natural history and immunologic status of patients with GLS are not fully known, although in some persons GLS may progress to full AIDS. We present the clinical and immunologic findings in two children with severe hemophilia A with nonprogressive GLS for 18-24 months. The functional activity in vitro of lymphocytes from both peripheral blood and biopsied lymph nodes were compared. The peripheral blood lymphocytes responded normally to both mitogens and antigens; lymph node lymphocytes failed to respond to antigens, but did respond to mitogens. The implications of these abnormalities for understanding the pathogenesis of GLS are discussed.

AIDS-Related Complex↗
PubMed1987

Haploidentical bone marrow transplantation for osteopetrosis.

HLA-matched bone marrow transplantation is an effective form of treatment for some patients with malignant osteopetrosis, a defect of osteoclast function. Following transplant, normal osteoclasts differentiate from donor-derived marrow stem cells and can function normally in some of these patients. For patients without an HLA-matched marrow donor, pharmacologic treatments have not yet proved effective. This article demonstrates that normal osteoclast function can be obtained following the transplantation of HLA-nonidentical marrow that has been purged of T lymphocytes in vitro.

Antilymphocyte Serum↗
PubMed1987

Evaluation of immunity.

Immunodeficiency disease is rapidly increasing in frequency. The AIDS epidemic, the increasing use of transplantation with immunosuppression, the aggressive immunotherapy, the persistent deficiencies after bone marrow transplantation--all contribute to the astronomically increasing numbers of patients with host defense failure. This review has presented my viewpoint as to the approaches which can be utilized by practitioners with varying focal points to provide diagnosis and maximize the potential for a cure today or at least to provide the beginnings of understanding from which will come the cures of tomorrow.

Antigens, Surface↗