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Biomedical subjects

J H Herman

Publications and source records attributed to J H Herman.

At least 19 recordsLinked to original sources
PubMed2000

Congenital myasthenic syndrome with sleep hypoventilation.

We report the case of a 13-year-old boy with acetylcholinesterase deficiency, a congenital myasthenic syndrome, who developed sleep hypoventilation syndrome during a period of rapid growth. His symptoms were insidious and life-threatening despite changes in strength or lung volume measurements that were not marked. He responded well to noninvasive nocturnal ventilation, with reversal of symptoms and normalization of blood gases. His lung volumes, but not motor function, improved after treatment.

Acetylcholinesterase↗
PubMed2000

Economic consequences of alterations in platelet transfusion dose: analysis of a prospective, randomized, double-blind trial.

BACKGROUND: In recent years, decreasing financial resources led to the use of lower-dose platelet components. However, the economic consequences of the use of such components have not been carefully studied. STUDY DESIGN AND METHODS: A formal economic analysis was conducted of a recently reported, prospective, randomized, double-blind study examining the platelet dose-response relationship in nonrefractory patients. The economic analysis used a decision analysis model, conducted from the hospital's perspective and based directly on the observed clinical data and on institutional cost structures. RESULTS: The decision analysis model estimated that a 38-percent reduction in mean platelet dose, within the commonly prescribed dose range, would result in the average patient's requiring approximately 60 percent more transfusions in the posttransplant period (8 vs. 5; p = 0.05), which would result in an estimated 60-percent increase in the median cost to the hospital ($4486/patient vs. $2804/patient [in 1996 US dollars], p = 0.05). CONCLUSION: Efforts to decrease costs by utilizing lower-dose single-donor platelet transfusions are predicted to result in a disproportionate increase in the number of transfusions per patient, with a corresponding increase in overall hospital transfusion costs.

Adult↗
PubMed1999

The development of circadian rhythms in a human infant.

STUDY OBJECTIVES: This study examines the ontogeny and interaction of circadian rhythms of sleep, wake, temperature, melatonin, and feeding in the human newborn, and the influence of photic and non-photic factors on the initiation of entrainment. DESIGN: An infant's sleep-wake state, temperature, and salivary melatonin were monitored from birth to 6 months. Temperature was obtained every hour, and the infant's sleep/eating onset/termination were observed continuously and recorded until day 182. Salivary melatonin was obtained weekly for a 24-hour period, starting at week 3. SETTING: The infant slept in his parents' bedroom. All household members awakened, retired, and ate meals according to a fixed schedule during the study, while the infant ate, slept, and woke on demand. PARTICIPANTS: A healthy male infant was the subject. Biological parents gathered data continuously for six months. INTERVENTIONS: The infant's schedule was on-demand; the household's was fixed. Illumination was restricted to sunlight. MEASUREMENTS AND RESULTS: The circadian rhythm of temperature appeared first, soon after birth, and became statistically significant within one week. The wake circadian rhythm appeared second, attaining significance at day 45; approximately the same time that increased melatonin concentration began to occur at sunset. The sleep circadian rhythm appeared last, attaining significance after day 56. Ninety to 120 minute zones of sustained wakefulness first appeared in the second month of life subsequent to awakening and prior to sleep onset. The infant's nocturnal sleep-onset was coupled to sunset before day 60 and subsequently to family bedtime, giving evidence of initial photic entrainment followed by social entrainment. CONCLUSIONS: Circadian rhythms appeared much more rapidly in this infant than previously reported; their rapid appearance was probably facilitated by maximal exposure to sunlight, and regular social cues. These lighting conditions replicate universal infant experience prior to the invention of artificial light.

Brain↗
PubMed1999

Clinical consequences of alterations in platelet transfusion dose: a prospective, randomized, double-blind trial.

BACKGROUND: The dose-response relationship for platelet transfusion has become increasingly important as the use of platelet transfusion has grown. STUDY DESIGN AND METHODS: One hundred fifty-eight prophylactic apheresis platelet transfusions were administered to 46 patients undergoing high-dose therapy followed by hematopoietic progenitor cell transplantation in a prospective, randomized, double-blind, multiple-crossover study. Transfusions were administered in pairs, differing only in platelet content. Each pair consisted of a lower-dose platelet component (LDP) and a higher-dose platelet component (HDP) administered in random order to the same patient. LDPs contained a mean of 3.1 x 10(11) platelets (range, 2.3-3.5 x 10(11)), and HDPs contained a mean of 5.0 x 10(11) platelets (range, 4.5-6.1 x 10(11)). Patients with active bleeding and those who were refractory to platelet transfusions were excluded. RESULTS: The mean posttransfusion platelet count increment with LDP was 17,010 per microL, and that with HDP was 31,057 per microL (p<0.0001). Only 37 percent of LDPs resulted in platelet count increments of at least 20,000 per microL, whereas 81 percent of HDPs resulted in increments above this level (p<0.0001). The mean transfusion-free interval with LDP was 2.16 days, whereas that with HDP was 3.03 days (p<0.01). Administration of LDPs was associated with a 39 to 82 percent increase in the relative risk (per day) of requiring subsequent platelet transfusions (p<0.0001). CONCLUSION: As compared to the administration of HDPs, the administration of LDPs for prophylactic transfusion in hematopoietic progenitor cell transplant patients results in a lower platelet count increment, a lower likelihood of obtaining a posttransfusion platelet increment >20,000 per microL, a shorter transfusion-free interval, and a greater relative risk per day of requiring additional transfusions.

Adolescent↗
PubMed1997

Plateletpheresis in 90- to 110-pound donors using the CS-3000 blood cell separator.

BACKGROUND: Increases in the use of single-donor apheresis components have increased the need for platelet donors. In the United States, persons must weigh 110 pounds or more to qualify as blood donors, and the same weight limitation has been placed on apheresis donors. Because automated plateletpheresis with some instruments differs considerably from whole-blood donation with respect to the volume of blood removed from the donor, the feasibility of using persons weighing between 90 and 110 pounds as platelet donors was evaluated by the use of the CS-3000 blood cell separator. STUDY DESIGN AND METHODS: The study was performed using female subjects who met all usual donor requirements except for minimum weight. The standard platelet collection procedure of the instrument was used, except that the blood processing rate was manually selected so as to optimize the blood withdrawal and return rate in individuals. Vital signs were recorded before and after donation as were signs or symptoms of any type of donor reaction. RESULTS: Twenty-six of 28 women completed the donation procedure; in two instances, collection was terminated prematurely because of an inability to maintain adequate venous access. An average of 4.5 x 10(11) platelets were collected during a mean donation time of 110 minutes. All donors tolerated the procedure well, and no serious adverse reactions were seen. Because of the administration of priming solution and anticoagulant during apheresis, there was a net positive fluid balance following the procedure, in spite of the removal of approximately 220 mL of platelet concentrate. CONCLUSION: These preliminary studies suggest that 90- to 110-pound persons may serve as plateletpheresis donors. Additional studies are needed to more fully document the safety and efficacy of this approach. The use of lower-weight donors may significantly increase the number of persons available to provide single-donor platelet components.

Blood Donors↗
PubMed1996

Uniaxial tension inhibits tendon collagen degradation by collagenase in vitro.

Tendon structure is governed largely by factors regulating the anabolic and catabolic phases of tenocyte metabolism. Little is known about the mechanisms that regulate the synthesis, activation, and action of metalloproteinases, which are key enzymes in a multifactorial cascade controlling homeostasis of the extracellular matrix. In the present study, we investigated the effect of tension on collagenase-induced degradation of the tendon in vitro by assessing changes in structural and material properties measured during tensile failure tests. Devitalized right-left pairs of rabbit patella-patellar tendon-tibia units were maintained under culture conditions in the presence of 60 U/ml highly purified collagenase for 20 hours. One randomly selected unit from each animal was subjected to a tension that produced a constant 4% elongation or strain (n = 10); the contralateral unit served as a slack comparison (n = 10). In one series of experiments (immediate, n = 5), the tension was applied immediately prior to collagenase exposure. In a second series (delayed, n = 5), it was delayed for 4 hours to allow time for the collagenase to diffuse into the tendon. Additional devitalized and nonincubated units (n = 6) were used as normal controls. Collagenase exposure caused large decreases in stiffness and elongation to failure in slack units. This resulted in greater than 80% reductions in both maximum failure force and energy to failure. In contrast, the loaded unit in both experimental protocols had significantly greater stiffness than control units. In both the immediate and the delayed protocols, the loaded tendons had significantly higher stiffness and failed at significantly higher elongations and maximum forces than the slack tendons. Diffusion studies with and without tension showed the tension did not inhibit diffusion of collagenase into the tendon but did significantly decrease the water content from 64.6 to 57.8%. The data suggest that stresses and strains of the extracellular matrix may modify the kinetics of the bacterial collagenase-collagen interaction. Matrix stress and strain may be an important and overlooked factor that modulates the susceptibility of collagen to proteolytic degradation.

Animals↗
PubMed1996

Factors associated with response to platelet transfusion following hematopoietic stem cell transplantation.

We studied 526 consecutive post-transplant platelet transfusions to determine the factors associated with response to platelet transfusion in the BMT setting. Poor responses to platelet transfusions occurred frequently, with 310 of the 484 evaluable transfusions (64%) resulting in post-infusion corrected count increments of less than 7500. Factors associated with poor response to platelet transfusion by both univariate and multivariate analysis included, (1) presence of serum lymphocytotoxic antibodies; (2) male sex; (3) body surface area greater than 1.7 m2; (4) transfusion of red cells on the day of the platelet infusion; (5) concurrent administration of steroids; (6) major ABO mismatch between the recipient and the platelet product; and (7) (among women) a history of one or more pregnancies prior to transplant. Paradoxically, a history of greater than 25 blood product exposures prior to transplant, and evidence of prior CMV infection in either the bone marrow donor or recipient were associated with higher CCIs by both univariate and multivariate analysis. Factors that showed little correlation with response to platelet transfusion included, (1) age of the infused platelet product; (2) concurrent fever; (3) recent administration of intravenous immunoglobulin; and (4) absolute neutrophil count at the time of the infusion. The factors associated with response to platelet transfusion in BMT patients appear to be different from those observed in the non-transplant setting.

ABO Blood-Group System↗
PubMed1996

Association between antibodies reactive with neutrophils, rate of neutrophil engraftment, and incidence of post-engraftment neutropenia following BMT.

Previous reports have suggested that antibodies reactive with neutrophils (ARN) are frequently detectable in patients undergoing bone marrow or blood stem cell transplantation (BMT), and that such antibodies result in steroid-responsive delayed neutrophil engraftment or steroid-responsive post-engraftment neutropenia in some patients. However, the true incidence and significance of ARN in the BMT setting remain poorly established because most of the published data are in the form of retrospective case reports. Therefore, we prospectively studied the incidence of ARN, the rate of neutrophil engraftment, and the incidence of post-engraftment neutropenia in a cohort of 40 BMT candidates. Sixteen of the 36 evaluable patients (44%) had detectable ARN following transplant vs none of 25 concurrently studied healthy controls (P < 0.0001). Patients with detectable ARN in the post-transplant period recovered to an absolute neutrophil count (ANC) of 500 x 10(9)/l a median of 3.5 days later than patients without detectable ARN; multivariate analysis controlling for the potential effects of diagnosis, conditioning regimen, amount of prior therapy, and other factors revealed that only the administration of hematopoietic growth factors (P = 0.008) and the presence of ARN in the post-transplant period (P = 0.016) were independently predictive of the rate of neutrophil engraftment following BMT. Four of the 16 patients with detectable ARN (25%) satisfied previously published criteria for post-engraftment neutropenia, ie a fall in the ANC to less than 500 x 10(9)/l for at least 2 consecutive days, following initial engraftment to an ANC of at least 1000 x 10(9)/l for at least 2 consecutive days. In contrast, none of the 20 patients without detectable post-transplant ARN developed post-engraftment neutropenia. Multivariate analysis revealed that only the presence of ARN in the post-transplant period (P = 0.022) was independently predictive of post-engraftment neutropenia. All four patients with ARN-associated post-engraftment neutropenia responded to steroid-based therapy. These prospectively gathered data support previously published primarily case report data suggesting that ARN occur frequently following BMT and are associated with an increased incidence of delayed neutrophil engraftment and post-engraftment neutropenia. As is the case in the non-transplant setting, ARN-associated neutropenia occurring following BMT may respond to steroid-based therapy.

Adolescent↗
PubMed1995

Fetal bleeding in neonatal alloimmune thrombocytopenia mediated by anti-PlAl is not associated with inhibition of fibrinogen binding to platelet GPIIb/IIIa.

Antibody directed against the platelet-specific alloantigen, PlAl, is the most frequently reported cause of two syndromes, post-transfusion purpura (PTP), and neonatal alloimmune thrombocytopenia (NAIT). Numerous reports have indicated that anti-PlAl also has the ability to block certain responses of platelets to stimulation, including fibrinogen binding, platelet aggregation, and serotonin release. Because the PlAl epitope is located on platelet membrane glycoprotein (GP) IIb/IIIa that also contains the fibrinogen receptor, these effects may be mediated by antibody binding at or near the fibrinogen receptor site. This study examines the capacity of anti-PlAl from patients with PTP and from mothers of infants affected by the NAIT to block the binding of radio-labeled fibrinogen to washed human platelets stimulated by ADP and epinephrine. In six of the seven PTP patients, there was inhibition of fibrinogen binding, ranging from 28% to 84% inhibition. In contrast, all anti-PlAl sera from nine mothers of infants with NAIT, including four with intracranial hemorrhage, failed to inhibit fibrinogen binding. Despite the generally higher anti-PlAl titers of the PTP sera, the ability to inhibit fibrinogen binding did not appear attributable to antibody titers. These results suggest that interference with fibrinogen binding to platelets by maternal anti-PlAl does not underlie the increased risk of bleeding in NAIT, whereas inhibitory activity directed against fibrinogen binding appears to be a characteristic feature of the sera from PTP patients.

Antigens, Human Platelet↗
PubMed1995

Vasculitis complicating granulocyte colony stimulating factor treatment of leukopenia and infection in Felty's syndrome.

Recombinant myeloid growth factors have been increasingly used in recent years to combat induced and disease associated neutropenia. Their application in the management of Felty's syndrome with intercurrent infection has raised concern that resultant neutrophilia and activation of a diverse array of polymorphonuclear cell functions may have an adverse effect on the rheumatoid disease process. We describe a patient with Felty's syndrome receiving short term treatment with recombinant human granulocyte colony stimulating factor (GCSF), who then developed acute renal failure in conjunction with leukocytoclastic vasculitis and presumptive gout. We address the issue of "adding fuel to the fire" and review reported implications of GCSF in induction of vasculitis.

Acute Kidney Injury↗
PubMed1994

Lack of transmission of neutrophil and platelet antibodies by intravenous immunoglobulin in bone marrow transplant patients.

BACKGROUND: Several studies have demonstrated that the administration of intravenous immunoglobulin (IVIG) may be followed by the transient appearance of positive red cell antibody screens, positive direct antiglobulin tests, and, occasionally, frank hemolysis. However, little information is available regarding the possibility that IVIG could transmit neutrophil and/or platelet antibodies. STUDY DESIGN AND METHODS: Serum samples were obtained both immediately before and immediately after the administration of 12 separate lots of commercially available IVIG to bone marrow transplant patients. RESULTS: None of the patients were shown by standard granulocyte immunofluorescence testing to have acquired neutrophil antibodies. Four of the 12 postinfusion sera were positive for platelet antibodies in standard platelet suspension immunofluorescence testing, but in all four instances the corresponding preinfusion serum was positive as well. CONCLUSION: The risk of acquiring neutrophil and/or platelet antibodies after the administration of commercially available IVIG appears to be low.

Blood Platelets↗
PubMed1994

Nonsteroidal antiinflammatory drug modulation of prosthesis pseudomembrane induced bone resorption.

OBJECTIVE: To study the in vitro effect of therapeutic levels of select nonsteroidal antiinflammatory drugs (NSAID) on prosthesis associated pseudomembrane induced bone resorption and cytokine and prostanoid synthesis using tissue obtained from osteoarthritic patients undergoing revision of cemented implants. METHODS: Pseudomembranes were cultured in the presence and absence of therapeutic levels of select NSAID: Processed conditioned media were evaluated for bone resorbing capacity by assessing murine neonatal limb rudiment release of 45Ca. Interleukin 1 (IL-1) and tumor necrosis factor (TNF) were analyzed by bioassay and prostaglandin E2 (PGE2) by radioimmunoassay. RESULTS: Piroxicam, in contrast to indomethacin and sodium salicylate, significantly decreased membrane associated bone resorption. The NSAID effect correlated more consistently with piroxicam downregulation of TNF synthesis than that of IL-1. Consistent drug associated suppression of PGE2 synthesis did not enable differentiation of NSAID effectiveness in suppressing pseudomembrane induced bone resorption. CONCLUSION: Results provide a rational basis for design of animal models and/or further human studies to test the hypothesis that the prophylactic administration of an NSAID can potentially retard the pseudomembrane effected bone resorptive process associated with aseptic cemented prosthesis failure.

Adult↗