Givosiran to treat acute porphyria.

Porphyrias are a family of rare diseases chiefly due to inborn errors of heme biosynthesis. The porphyrias are generally characterized either by the main site of overproduction of heme precursors (hepatic or erythropoietic) or the main clinical manifestations (acute or cutaneous). The regulation of 5- (or δ)-aminolevulinic acid synthase 1 (ALAS1) plays a key role in the pathway of normal hepatic heme synthesis, providing insight into the pathophysiologic mechanisms and potential therapeutic targets for the treatment of the porphyrias. Givosiran (Givlaari; Alnylam Pharmaceuticals) is an ALAS1-directed small interfering RNA (siRNA) which has been developed for the treatment of acute hepatic porphyria (AHP). It was first approved in 2019 by the U.S. Food and Drug Administration (FDA) for the treatment of adult patients with AHP, and it received also approval in the E.U. in 2020 for the treatment of AHP in adults and adolescents aged 12 years and older.

Influence of ceiling fan's speed and direction on efficacy of upperroom, ultraviolet germicidal irradiation: Experimental.

Increasing a ceiling fan's speed from its lowest setting of 61 rpm, which resulted in 0.77 m3/s of airflow, to its highest setting of 176 rpm, which resulted in 2.5 m3/s of airflow, or having the fan blow either upward or downward had no statistically significant effect on the efficacy of upper-room ultraviolet germicidal irradiation (UVGI). This outcome suggests that air circulation due to the ceiling fan was sufficient and that any additional increase would not improve efficacy. Numerous experimental studies on upper-room UVGI in which fans were used to provide air mixing have been published. However, none have quantified the air movement produced by these fans or described their tests in sufficient detail to allow results to be compared to predictions using computational fluid dynamics (CFD). The present work provides the required information. In addition to the usual boundary conditions needed for CFD, we made experimental measurements of UV susceptibility of the microorganisms used in the upper-room UVGI tests. We measured UV susceptibilities for Mycobacterium parafortuitum and Bacillus atrophaeus spores to be 0.074 and 0.018 m2/J, respectively. In a previous publication, we reported the spatial distribution of fluence rate, which is also needed for predicting efficacy from CFD. In a companion paper referred to as Part II, upper-room UVGI efficacy was predicted by both Eulerian and Lagrangian CFD and compared to the experimental results from the present study.

Eggcrate UV: a whole ceiling upper-room ultraviolet germicidal irradiation system for air disinfection in occupied rooms.

A novel whole ceiling upper-room ultraviolet germicidal irradiation (UVGI) system [eggcrate ultraviolet (UV)] has been developed that incorporates open-cell 'eggcrate'-suspended ceiling panels and bare UV lamps with a ceiling fan. Upper-room UVGI is more effective for air disinfection than mechanical ventilation at much lower installation and operating costs. Conventional upper-room UVGI fixtures employ multiple tightly spaced horizontal louvers to confine UV to the upper-room. These louvered fixtures protect occupants in the lower-room from UV-induced eye and skin irritation, but at a major cost to fixture efficiency. Using a lamp and ballast from a conventional upper-room UVGI fixture in the eggcrate UV system, the germicidal efficacy was markedly improved even though the UV radiation emitted by the lamp was unchanged. This fundamental change in the application of upper-room UVGI air disinfection should permit wider, more effective application of UVGI globally to reduce the spread of airborne infection.

Risk of indoor airborne infection transmission estimated from carbon dioxide concentration.

The Wells-Riley equation, which is used to model the risk of indoor airborne transmission of infectious diseases such as tuberculosis, is sometimes problematic because it assumes steady-state conditions and requires measurement of outdoor air supply rates, which are frequently difficult to measure and often vary with time. We derive an alternative equation that avoids these problems by determining the fraction of inhaled air that has been exhaled previously by someone in the building (rebreathed fraction) using CO2 concentration as a marker for exhaled-breath exposure. We also derive a non-steady-state version of the Wells-Riley equation which is especially useful in poorly ventilated environments when outdoor air supply rates can be assumed constant. Finally, we derive the relationship between the average number of secondary cases infected by each primary case in a building and exposure to exhaled breath and demonstrate that there is likely to be an achievable critical rebreathed fraction of indoor air below which airborne propagation of common respiratory infections and influenza will not occur.

Predicting the ultraviolet radiation distribution in a room with multilouvered germicidal fixtures.

Irradiating the upper part of a room with 254-nm ultraviolet (UV) radiation from a low-pressure mercury discharge lamp has the potential to be a relatively inexpensive method to reduce transmission of airborne infectious diseases such as tuberculosis. To protect occupants in the lower part of a room from radiation, multilouvered UV germicidal fixtures producing a horizontal, collimated beam are often used, particularly in rooms having a normal ceiling height. Knowledge of the fixture's emission characteristics and the airflow field are needed to estimate the UV dose to airborne microorganisms and assess the fixture's overall effectiveness in controlling disease transmission. In this article, a model is developed to predict the UV fluence rate at any location in the upper room for ceiling-mounted, multilouvered, pendant-type fixtures, which provide 360-degree emission in the horizontal plane. The model also predicts total UV power emitted by the fixture, which is the best single-number effectiveness index for comparing multilouvered UV germicidal fixtures. Model predictions compared favorably with laboratory and field measurements.

Laser-induced fluorescence of pyrene and other polycyclic aromatic hydrocarbons (PAH) in seawater.

Polycyclic aromatic hydrocarbons (PAH) in the marine environment are currently of great concern due to their potential carcinogenicity. The standard methods of detection and quantification of PAH in seawater and sediments are costly, time-consuming and do not account for the heterogeneous nature of their distribution and sources. Laser-induced, time-resolved fluorescence spectroscopy may help to overcome these limitations. Several PAH have relatively long-lived stimulated fluorescence emissions, which allow them to be detected among a background of more intense but shorter-lived chromophores. Using time-delayed techniques we have shown an ability to detect PAH, principally pyrene, at environmental levels (ng l(-1)) both in the laboratory and in situ in Boston Harbor and other study areas. Further development may lead to the rapid determination of several PAH in typical near-shore marine environments.

Recombinant human erythropoietin therapy for anemic cancer patients receiving cisplatin chemotherapy.

PURPOSE: To assess whether the administration of recombinant human erythropoietin (r-HuEPO) would increase the hematocrit, reduce the requirement for transfusion, and improve the quality of life in anemic cancer patients receiving myelosuppressive, cisplatin-based chemotherapy. PATIENTS AND METHODS: One hundred thirty-two anemic cancer patients receiving cyclic, cisplatin-containing, myelosuppressive chemotherapy were evaluated. Patients received either r-HuEPO (150 U/kg) or placebo, subcutaneously, three times a week for 3 months. Responses were assessed by measuring changes in hemoglobin/hematocrit, transfusion requirement, and quality of life. RESULTS: The mean hematocrit increased by 6.0 percentage points in the r-HuEPO group versus 1.3 in the placebo group. A decrease in transfusion requirement did not reach significance over all 3 months, but there was a significant reduction in the percentage of patients transfused in the second and third months (27% r-HuEPO vs. 56% placebo) and a trend toward reduction in the mean total number of units transfused (1.20 units r-HuEPO vs. 2.02 units placebo), suggesting a lag of 1 month before r-HuEPO can affect the transfusion requirement. Pretreatment serum erythropoietin levels were lower in responders than in nonresponders (73.5 IU/L and 86.3 IU/L means, respectively). However, the magnitude of this difference was not helpful in defining which patients were likely to respond. There was a significant improvement in overall quality of life between the two treatment arms in favor of the r-HuEPO-treated group. There were no significant adverse effects associated with r-HuEPO. CONCLUSIONS: r-HuEPO is safe and can cause a significant improvement in the hematocrit and quality of life of anemic cancer patients receiving myelosuppressive, cisplatin-based chemotherapy. After 1 month of r-HuEPO, there is also a reduction in transfusion requirement.

Myosin heavy chain synthesis is independently regulated in hypertrophy and atrophy of isolated adult cardiac myocytes.

Hypertrophy of isolated adult feline cardiac muscle cells may be induced in culture by either alpha- or beta-adrenergic agonists. However, it has been shown previously that each of these agonists activate different subsets of immediate-early response genes and have different effects on expression of "fetal" protein isoforms and stimulation of protein synthesis. Moreover, in adult feline heart cells, beta-adrenergic agonists, such as isoproterenol, activate sustained synchronous beating and sarcomeric reorganization while alpha-adrenergic agonists, such as phenylephrine, do not. The objective of the present study was to determine whether these differences in proximal signaling events converged in a common signal pathway during activation of contractile protein synthesis. By direct comparisons of actin and myosin heavy chain (HC) synthesis and accumulation following isoproterenol and phenylephrine, it was determined that both agonists stimulate a coordinated accumulation of these proteins during cardiomyocyte growth. However, each agonist stimulated a very different program of contractile protein synthesis. During phenylephrine-induced hypertrophy, actin and myosin HC syntheses were rapidly and coordinately activated and continuously maintained at rates 10-25% greater than untreated cultures. The pattern of myosin HC synthesis following isoproterenol was very much more complex with periods during which it was as much as 40% greater or 25% less than in control cultures. Furthermore, there was no correlation between rates of actin and myosin HC synthesis following isoproterenol. It was concluded that actin and myosin HC syntheses and accumulation were regulated independently and in a very different manner following isoproterenol or phenylephrine. Since protein accumulation was not correlated with synthesis rates during development of hypertrophy, it was also concluded that post-translational mechanisms played a significant role in the maintenance of contractile protein stoichiometry during beta-adrenergic/beating-induced hypertrophy. Myosin HC synthesis also appeared to be independently regulated during cardiomyocyte atrophy induced by the calcium channel blocker nifedipine. Unlike the case in hypertrophy, however, protein balance was not maintained in nifedipine, and the depression of myosin HC synthesis and loss of myosin HC content were much greater than in the case of other contractile proteins.

Comparison of the utility of capillary zone electrophoresis and high-performance liquid chromatography in peptide mapping and separation.

Capillary zone electrophoresis (CZE) and high-performance liquid chromatography (HPLC) have been used in the analysis of the primary structure of recombinant human insulin-like growth factor I (rhIGF-I). CZE both complements and supplements HPLC separations. CZE has been used to resolve peaks which co-elute on HPLC, as well as to help establish the identity of tryptic fragments in peptide mapping experiments.

Regulation of hypertrophy and atrophy in cultured adult heart cells.

Mechanical loading and alpha-adrenergic receptor stimulation have both been shown to induce hypertrophy in isolated neonatal heart cells. The present study examined the effects of adrenergic hormones and contractile activity on the hypertrophic response in isolated adult feline cardiomyocytes maintained for more than 14 days in insulin- and serum-supplemented medium. Measurements of the hypertrophic response included cell size, total protein content, myosin heavy chain content, and the time course of activation of increased protein synthesis. Reactivation of the "fetal" gene program was evaluated by secretion of atrial natriuretic factor (ANF) into the medium. Significant myocyte hypertrophy was induced in both quiescent myocytes treated with alpha 1-adrenergic agonists and in beating myocytes treated with beta-adrenergic agonists. However, there were both quantitative and qualitative differences in the response to each type of stimulation. alpha-Adrenergic agonists promoted an increase in cell size, protein content, and ANF secretion but not myofibrillar reorganization, which was observed only in beating myocytes. In contrast to results reported for neonatal heart cells, determinants of hypertrophy in beating myocytes exceeded those in nonbeating alpha 1-adrenergic agonist-treated heart cells in every parameter examined. In addition, in the case of both beating and alpha-adrenergic stimulation, there were marked time-dependent variations in rates of protein synthesis over the interval of 4 hours to 7 days of treatment with each type of stimulus. Differences were also encountered in correlations between rates of protein synthesis and protein accumulation over this interval. The effect of beating was particularly important both to the reorganization of myofibrillar structure and the metabolism of myosin heavy chain. In cultures in which beating was inhibited with the calcium channel antagonist nifedipine, the loss of myosin heavy chain was significantly greater than that of total protein.

Protein and peptide mobility in capillary zone electrophoresis. A comparison of existing models and further analysis.

Capillary zone electrophoresis of peptide fragments from the tryptic digest of human recombinant insulin-like growth factor I (rhIGF-I) has been carried out and the observed mobilities used to compare the relative applicability of existing mobility models. In addition, the physical forces affecting electromigration have been systematically analyzed in order to more accurately describe the physical chemistry involved. Such an approach should further improve the ability to predict electrophoretic mobility in capillary zone electrophoresis.

Cultured adult cardiac myocytes maintain protein synthetic capacity of intact adult hearts.

Previous studies have shown that the rates of protein synthesis observed in embryonic and neonatal heart cells in culture are as much as nine times greater than the rates of synthesis observed in the intact adult heart either in situ or in isolated perfusion studies. This study addressed whether adult cardiomyocytes in long-term culture maintain the protein synthetic capacity of the adult myocardium or, rather, whether the protein synthetic capacity expands or falls as adult cardiac myocytes progress in culture. Protein synthesis was evaluated in isolated adult feline cardiomyocytes maintained in serum and insulin-supplemented medium for up to 53 days in vitro. With the use of both pulse- and saturation-labeling techniques it was determined that the rate of protein synthesis in adult cardiomyocytes was maintained at a level very close to that observed in the intact heart for over 1 mo in culture. Saturation-labeling studies indicate a fractional rate of protein synthesis at 6.1%/day and an absolute synthesis rate of 1,300 nmol leucine incorporated.g protein-1.h-1. Pulse-labeling studies revealed an initial increase in protein synthesis rates during adaptation to culture and a further increase after activation of beating and cellular hypertrophy.

Preoperative red cell production in patients undergoing aggressive autologous blood phlebotomy with and without erythropoietin therapy.

Previous studies have demonstrated that autologous blood donors have a suboptimal endogenous erythropoietin response to the mild anemia induced by blood donation. Recent studies in baboons subjected to aggressive phlebotomy have shown an acceleration of erythropoiesis that may be beneficial perioperatively. To address the issue of accelerated erythropoiesis in autologous blood donors, red cell production during an aggressive preoperative autologous blood donation program was analyzed. The volume of red cells increased 568 mL (27% over baseline) and 911 mL (47% over baseline) for 23 placebo and 21 erythropoietin-treated patients, respectively, by hospital admission (9 days after last drug administration and 26 days after beginning therapy). The mean rate of additional red cell production was 22 mL per day in the placebo group and 34 mL per day in the erythropoietin group (p less than 0.001), which represents a twofold and a 2.5-fold increase over basal erythropoiesis, respectively. The major difference in red cell production in the placebo and erythropoietin groups occurred early in the collection period. It can be concluded that an aggressive autologous blood phlebotomy program results in clinically important increased erythropoiesis at the time of surgery. In patients unsuited for aggressive autologous phlebotomy, a more modest autologous blood procurement program, coupled with the administration of recombinant erythropoietin, may be a preferable approach.

OKT3E, an anti-CD3 antibody that does not elicit side effects or antiidiotype responses in chimpanzees.

Chimpanzees were injected with OKT3 and two other anti-CD3 antibodies, OKT3D and OKT3E. Both of the new antibodies were of the mouse IgG2b isotype. Administration of the antibodies was identical to the clinical regimen used for OKT3 in humans: 5 mg i.v., daily for 10 consecutive days. All animals were monitored for fever during administration of the antibodies, and blood samples were taken throughout the treatment period for monitoring the effects of the antibodies on peripheral lymphocyte subsets and the appearance of circulating cytokines. OKT3 produced similar clinical effects to those observed in humans; fever (2/3), as well as elevations in cytokines were observed. As in humans, peripheral T cells were cleared with the first dose and remained absent or modulated of their T cell receptor molecules throughout treatment. OKT3D, IgG2b also produced fevers (2/3) and elevations of cytokines. Although it also cleared circulating T cells with the first dose and T cell counts remained low throughout treatment, remaining circulating T cells were coated with administered antibody and were able to reexpress the CD3 antigen. OKT3E, IgG2b produced no temperature elevations and no elevations in cytokines. Although it cleared the circulation of T cells with the first does, cells reappeared during treatment, modulated of their CD3 antigens or coated with the administered antibody. All three antibodies raised antimouse antibodies, and OKT3 and OKT3D also produced blocking antiidiotype antibodies. OKT3E treatment did not result in anti-OKT3E blocking antibodies.

Iron-restricted erythropoiesis as a limitation to autologous blood donation in the erythropoietin-stimulated bone marrow.

Recombinant human erythropoietin has been demonstrated to significantly increase autologous blood procurement. To determine the importance of dietary or prescribed iron absorption, we analyzed iron-restricted erythropoiesis in this setting. No differences were found when premenopausal placebo and erythropoietin treatment groups were compared for hematocrit changes, number of units donated, percentage of phlebotomies deferred, and total blood volume procured. Seven of 10 women who had not reached menopause donated more blood iron than the apparent amount of total mobilizable iron available, demonstrating that dietary or prescribed iron had to be absorbed to donate the amount of blood iron stored. Thus oral iron absorption can potentially be a limitation to erythropoiesis in the presence of erythropoiesis therapy in women who have not reached menopause. In contrast, none of 16 women who had reached menopause and only two of 21 men required oral absorption of dietary or prescribed iron for the amount of blood iron donated. We conclude that although oral iron supplementation may not be necessary in men and in women who have reached menopause, alternatives to oral ferrous salt supplementation could be tested to determine whether such alternatives would improve the response to erythropoiesis in premenopausal women.