Cardiovascular subphenotypes in patients with COVID-19 pneumonitis whose lungs are mechanically ventilated: a single-centre retrospective observational study.

Unsupervised clustering methods of transthoracic echocardiography variables have not been used to characterise circulatory failure mechanisms in patients with COVID-19 pneumonitis. We conducted a retrospective, single-centre cohort study in ICU patients with COVID-19 pneumonitis whose lungs were mechanically ventilated and who underwent transthoracic echocardiography between March 2020 and May 2021. We performed latent class analysis of echocardiographic and haemodynamic variables. We characterised the identified subphenotypes by comparing their clinical parameters, treatment responses and 90-day mortality rates. We included 305 patients with a median (IQR [range]) age 59 (49-66 [16-83]) y. Of these, 219 (72%) were male, 199 (65%) had moderate acute respiratory distress syndrome and 113 (37%) did not survive more than 90 days. Latent class analysis identified three cardiovascular subphenotypes: class 1 (52%; normal right ventricular function); class 2 (31%; right ventricular dilation with mostly preserved systolic function); and class 3 (17%; right ventricular dilation with systolic impairment). The three subphenotypes differed in their clinical characteristics and response to prone ventilation and outcomes, with 90-day mortality rates of 22%, 42% and 73%, respectively (p < 0.001). We conclude that the identified subphenotypes aligned with right ventricular pathophysiology rather than the accepted definitions of right ventricular dysfunction, and these identified classifications were associated with clinical outcomes.

Marked differences in local bone remodelling in response to different marrow stimulation techniques in a large animal.

Marrow stimulation, including subchondral drilling and microfracture, is the most commonly performed cartilage repair strategy, whereby the subchondral bone plate is perforated to release marrow-derived cells into a cartilage defect to initiate repair. Novel scaffolds and therapeutics are being designed to enhance and extend the positive short-term outcomes of this marrow stimulation. However, the translation of these newer treatments is hindered by bony abnormalities, including bone resorption, intralesional osteophytes, and bone cysts, that can arise after marrow stimulation. In this study, three different marrow stimulation approaches - microfracture, subchondral drilling and needle-puncture - were evaluated in a translationally relevant large-animal model, the Yucatan minipig. The objective of the study was to determine which method of marrow access (malleted awl, drilled Kirschner wire or spring-loaded needle) best preserved the underlying subchondral bone. Fluorochrome labels were injected at the time of surgery and 2 weeks post-surgery to capture bone remodelling over the first 4 weeks. Comprehensive outcome measures included cartilage indentation testing, histological grading, microcomputed tomography and fluorochrome imaging. Findings indicated that needle-puncture devices best preserved the underlying subchondral bone relative to other marrow access approaches. This may relate to the degree of bony compaction occurring with marrow access, as the Kirschner wire approach, which consolidated bone the most, induced the most significant bone damage with marrow stimulation. This study provided basic scientific evidence in support of updated marrow stimulation techniques for preclinical and clinical practice.

Long term outcomes of biomaterial-mediated repair of focal cartilage defects in a large animal model.

The repair of focal cartilage defects remains one of the foremost issues in the field of orthopaedics. Chondral defects may arise from a variety of joint pathologies and left untreated, will likely progress to osteoarthritis. Current repair techniques, such as microfracture, result in short-term clinical improvements but have poor long-term outcomes. Emerging scaffold-based repair strategies have reported superior outcomes compared to microfracture and motivate the development of new biomaterials for this purpose. In this study, unique composite implants consisting of a base porous reinforcing component (woven poly(ε-caprolactone)) infiltrated with 1 of 2 hydrogels (self-assembling peptide or thermo-gelling hyaluronan) or bone marrow aspirate were evaluated. The objective was to evaluate cartilage repair with composite scaffold treatment compared to the current standard of care (microfracture) in a translationally relevant large animal model, the Yucatan minipig. While many cartilage-repair studies have shown some success in vivo, most are short term and not clinically relevant. Informed by promising 6-week findings, a 12-month study was carried out and those results are presented here. To aid in comparisons across platforms, several structural and functionally relevant outcome measures were performed. Despite positive early findings, the long-term results indicated less than optimal structural and mechanical results with respect to cartilage repair, with all treatment groups performing worse than the standard of care. This study is important in that it brings much needed attention to the importance of performing translationally relevant long-term studies in an appropriate animal model when developing new clinical cartilage repair approaches.

A time-sensitive analysis of the prognostic utility of vasopressor dose in septic shock.

It is unclear whether the association between vasopressor dose and mortality is affected by duration of administration. We examined whether prognostication in septic shock is feasible through the use of daily median vasopressor doses. We undertook a single-centre retrospective cohort study. We included patients with a diagnosis of septic shock admitted to the intensive care unit at Queen Elizabeth Hospital, Birmingham, UK, between April 2016 and July 2019. The primary outcome measure was 90-day mortality. We defined vasopressor dose as the median norepinephrine equivalent dose (equivalent infusion rates of all vasopressors and inotropes) recorded for each day, for the first four days of septic shock. We divided patients into groups by vasopressor dose quintiles and calculated their 90-day mortality rate. We examined area under the receiver operator characteristic curves for prognostic ability. In total, 844 patients were admitted with septic shock and had a 90-day mortality of 43% (n = 358). Over the first four days, median vasopressor dose decreased in 93% of survivors and increased in 56% of non-survivors. The mortality rate associated with a given vasopressor dose quintile increased on sequential days of septic shock. The area under the receiver operator characteristic curves of daily median vasopressor dose against mortality increased from day 1 to day 4 (0.67 vs. 0.86, p < 0.0001). By day 4, a median daily vasopressor dose > 0.05 µg.kg-1 .min-1 had an 80% sensitivity and specificity for mortality. The prognostic utility of vasopressor dose improved considerably with shock duration. Prolonged administration of small vasopressor doses was associated with a high attributable mortality.

Renal impairment and its impact on clinical outcomes in patients who are critically ill with COVID-19: a multicentre observational study.

Renal impairment is common in patients who are critically ill with coronavirus disease-19 (COVID-19). We examined the association between acute and chronic kidney disease with clinical outcomes in 372 patients with coronavirus disease-19 admitted to four regional intensive care units between 10 March 2020 and 31 July 2020. A total of 216 (58%) patients presented with COVID-19 and renal impairment. Acute kidney injury and/or chronic kidney disease was associated with greater in-hospital mortality compared with patients with preserved renal function (107/216 patients (50%) (95%CI 44-57) vs. 32/156 (21%) (95%CI 15-28), respectively; p < 0.001, relative risk 2.4 (95%CI 1.7-3.4)). Mortality was greatest in patients with renal transplants (6/7 patients (86%) (95%CI 47-100)). Mortality rates increased in patients with worsening renal injury according to the Kidney Disease: Improving Global Outcomes classification: stage 0 mortality 33/157 patients (21%) (95%CI 15-28) vs. stages 1-3 mortality 91/186 patients (49%) (95%CI 42-56); p < 0.001, relative risk 2.3 (95%CI 1.7-3.3). Survivors were less likely to require renal replacement therapy compared with non-survivors (57/233 patients (24%) vs. 64/139 patients (46%), respectively; p < 0.001, relative risk 1.9 (95%CI 1.4-2.5)). One-fifth of survivors who required renal replacement therapy acutely in intensive care continued to require renal support following discharge. Our data demonstrate that renal impairment in patients admitted to intensive care with COVID-19 is common and is associated with a high mortality and requirement for on-going renal support after discharge from critical care. Our findings have important implications for future pandemic planning in this patient cohort.

Chronic Pruritus: A Review of Neurophysiology and Associated Immune Neuromodulatory Treatments.

Chronic pruritus remains a difficult condition to treat with many non-specific therapeutic options. Recent scientific discoveries have elucidated the physiology associated with pruritus. Combined with clinical and experimental trials with immune-modulatory agents, chronic pruritus now has novel treatment options with known mechanisms of action. This review goes over recent scientific progress in understanding the molecular mechanisms governing pruritus, the cross-talk between the immune and nervous systems that regulate itch, and central nervous pathways and projections affected by itch. In light of these recent discoveries, we briefly discuss a growing body of data from relevant clinical trials investigating immunomodulatory drugs targeting specific interleukin receptors (IL-4/13/31) and intracellular signaling (e.g., Janus kinase) pathways. We focus on the physiological processes that control this complex physical and emotional experience, as well as the role of newer drugs used to treat chronic itch.

Metabolism and pulmonary toxicity of cyclophosphamide.

Pulmonary toxicity caused by an antineoplastic drug, cyclophosphamide is becoming a more frequently recognized entity. Metabolism of cyclophosphamide in lung to alkylating metabolites and acrolein, a reactive aldehyde are in part responsible for pulmonary toxicity. Alterations in pulmonary mixed-function oxidase activity, glutathione content, and microsomal lipid peroxidation may be caused by the reactive metabolite acrolein. Potentiation of cyclophosphamide-induced pulmonary injury under hyperoxic conditions is caused by depression of pulmonary antioxidant defense mechanisms by cyclophosphamide and its other metabolites but not acrolein. Cyclophosphamide- and acrolein-induced alterations in the physical state of membrane lipid bilayer may be the major cause of inactivation of membrane-bound enzymes. These data suggest that cyclophosphamide and its reactive metabolites initiate peroxidative injury resulting in alterations in the physical state of membrane lipids which may be functionally linked to manifestations of cyclophosphamide-induced pulmonary toxicity.

Selective culture of primate marrow-derived macrophages in medium devoid of protein additives.

Viable cultures of bone marrow-derived macrophages (BMM phi) from a primate source, the baboon, were maintained for up to 4 weeks in culture in the absence of any exogenous protein in the medium. Baboon peripheral blood monocytes, spleen, lung, and liver M phi s or human BMM phi failed to survive for greater than 4 days. The protein-free BMM phi cultures were morphologically distinctive by virtue of the extremely dendritic appearance of the M phi s. In contrast baboon marrow cultured in the presence of fetal calf serum led to the overgrowth of fibroblastoid cells and in the presence of horse serum produced numbers of giant cells or polykaryocytes in addition to M phi s. The BMM phi were capable of nonimmune phagocytosis of yeast particles, expressed Ia antigen on their surfaces (59%), and were positive cytochemically for nonspecific (alpha-naphthyl acetate) esterase, oil red O, and tartrate resistant acid phosphatase. The addition of sera to established protein-free BMM phi cultures induced a rapid change of shape, viz., retraction of the dendritic processes and rounding up of the M phi s apparent within 10 min. This shape change was not induced by the addition of hemopoietic growth factors granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte CSF (G-CSF), macrophage CSF (M-CSF), or interleukin 3 (IL-3), nor could it be inhibited by the calcium channel blocking agent Nifedipine. Low levels of M-CSF activity, assayed by the murine bone marrow proliferation assay, were detected in the supernatant.

Diagnosis of peste des petits ruminants infection in small ruminants through in-house developed Indirect ELISA: Practical considerations.

AIM: The work was conducted to diagnose peste des petits ruminants (PPR) outbreak through an in house developed indirect ELISA (thereafter referred as iELISA) its comparison with other available diagnostic tests and description of practical considerations in its development, utility and limitations. MATERIALS AND METHODS: An outbreak resembled to PPR occurred in two different places of southern Gujarat viz. Vapi and Navsari, affecting 622 animals, including both goat (n = 476) and sheep (n = 146). Animals displayed the typical signs of PPR at Vapi; however diarrhea was the inconsistent feature in animals of Navsari. The affection caused morbidity of 100% and mortality were 73.68% (n = 392/532) and 56.67% (n = 51/90) in Vapi and Navsari outbreaks, respectively. Relevant ante mortem and post mortem samples were collected from representative animals. At the outset of the epidemic no kit was available with us, so agar gel immunodiffusion (AGID) was carried out and a commercial ELISA (cELISA) kit was ordered for making diagnosis through antibody demonstration. Meanwhile, an iELISA was developed in house using PPR vaccine as antigen and protein G conjugated HRPO antibody as detector. Histopathology and results of sandwich ELISA were also used to diagnose PPR virus (PPRV) in the outbreak. RESULTS: The iELISA developed had detected PPRV antibodies in 22/24 samples (91.66%). Significant difference was observed in disease sensitivity pattern of two species by Chi-square test. While AGID failed to detect antibodies in any sample. Results were reconfirmed by comparing with commercially available cELISA kit. CONCLUSION: PPR is an economically important disease and for the rapid diagnosis of PPR the in house developed antibody capture iELISA can be a suitable cost effective alternative.

The effect of oxidant gases on membrane fluidity and function in pulmonary endothelial cells.

Free radicals and oxidant gases, such as oxygen (O2) and nitrogen dioxide (NO2), are injurious to mammalian lung cells. One of the postulated mechanisms for the cellular injury associated with these gases and free radicals involves peroxidative cleavage of membrane lipids. We have hypothesized that oxidant-related alterations in membrane lipids may result in disordering of the plasma membrane lipid bilayer, leading to derangements in membrane-dependent functions. To test this hypothesis, we examined the effect of exposure to high partial pressures of O2 or NO2 on the physical state and function of pulmonary endothelial cell plasma membranes. Both hyperoxia (95% O2 at 1 ATA) and NO2 exposure (5 ppm) caused early and significant decreases in fluidity in the hydrophobic interior of the plasma membrane lipid bilayer and subsequent depressions in plasma membrane-dependent transport of 5-hydroxytryptamine. Lipid domains at the surface of pulmonary endothelial cell plasma membranes are more susceptible to NO2-induced injury than to hyperoxic injury. Alterations in the fluidity of these more superficial domains are associated with derangements in surface dependent functions, such as receptor-ligand interaction. These results support our hypothesis and advance our understanding of how the chemical events of free radical injury associated with high O2 and NO2 tensions are translated into functional manifestations of O2 and NO2-induced cellular injury.

Overexpression of plasma membrane annexin II in NO2-exposed pulmonary artery endothelial cells.

Because exposure to nitrogen dioxide (NO2) alters plasma membrane structure and function in pulmonary artery endothelial cells (PAEC), we examined whether NO2 exposure is associated with upregulation of plasma membrane-specific proteins in PAEC. Exposure to 5 ppm NO2 for 24 h had no significant effect on total protein synthesis. However, two-dimensional gel electrophoresis of isolated plasma membranes from [35S]-methionine pulse-labeled PAEC exposed to NO2 for 24 h demonstrated 3- to 9-fold increases in the synthesis of several proteins with molecular masses of 36, 39, and 40 kDa compared with controls. N-terminal amino acid sequencing and immunodetection analysis identified the 36kDa plasma membrane protein as annexin II (lipocortin II). Northern blotting analysis demonstrated that the mRNA expression for annexin II in NO2-exposed cells was also increased. These results suggest that exposure to NO2 results in induction of plasma membrane annexin II, an important multifunctional calcium- and phospholipid-binding protein in PAEC.

Nitrogen dioxide-induced expression of a 78 kDa protein in pulmonary artery endothelial cells.

Exposure to nitrogen dioxide (NO2) activates signal transduction in cultured pulmonary artery endothelial cells (PAEC). We examined whether NO2-induced activation of signal transduction results in increased expression of proteins in PAEC. Exposure to 5 ppm NO2 for 4, 12, and 24 h had no significant effect on total protein synthesis. However, two-dimensional gel electrophoresis of [35S]-methionine-labeled PAEC exposed to NO2 for 24 h, but not 4 and 12 h, demonstrated increased synthesis of several proteins including a two- to five-fold increase of some proteins with molecular masses of 47, 64, 78, and 105 kDa compared to controls. N-terminal amino acid sequencing and immunodetection analysis identified the 78 kDa protein as 78 kDa glucose-regulated protein (GRP-78). Induction of GRP-78 by NO2 exposure was regulated at the transcriptional level, and the induction required de novo protein synthesis. Exposure to NO2 for 24 h also significantly (p < .05) decreased glycosylation of proteins in PAEC. Exposure of cell monolayers to tunicamycin, an inhibitor of protein glycosylation, mimicked the effect of NO2 exposure on expression of GRP-78. Increased expression of GRP-78 was also detected when cell monolayers were exposed to the calcium ionophore A 23187, to 2-deoxyglucose, or to glucose-free medium, which are also known to cause perturbations in protein glycosylation. These results demonstrate that exposure to NO2 increases expression of a number of proteins including GRP-78 in PAEC. Increased expression of GRP-78 in NO2-exposed cells appears to be associated with inhibition of glycosylation or through coordinated alterations in metabolic events that lead to inhibition of protein glycosylation.

NO2-induced expression of specific protein kinase C isoforms and generation of phosphatidylcholine-derived diacylglycerol in cultured pulmonary artery endothelial cells.

The present study examines whether nitrogen dioxide (NO2)-induced activation of protein kinase C (PKC) is associated with increased expression of specific PKC isoforms and/or with enhanced generation of phosphatidylcholine(PC)-derived diacylglycerol (DAG) in pulmonary artery endothelial cells (PAEC). Western blot analysis revealed that exposure to 5 ppm NO2 resulted in increased expression of PKC alpha and epsilon isoforms in both cytosol and membrane fractions in a time-dependent fashion compared with controls. A time-dependent elevated expression of PKC isoform beta was observed in the cytosol fraction only of N02-exposed cells. PKC isoform gamma was not detectable in either the cytosolic or membrane fractions from control or N02-exposed cells. Scatchard analysis of [3h]phorbol 12,13-dibutyrate (PDBu) binding showed that exposure to N02 for 24 h increased the maximal number of binding sites (Bmax) from 15.2 +/- 2.3 pmol/mg (control) to 42.3 +/- 5.3 pmol/mg (p < 0.01, n = 4) (NO2-exposed). Exposure to NO2 significantly increased PC specific-phospholipase C and phospholipase D activities in the plasma membrane of PAEC (p < 0.05 and p < 0.001, respectively). When [3H]-myristic acid-labeled cells were exposed to NO2, significantly increased radioactivity was associated with cellular DAG. These results show for the first time that exposure of PAEC to NO2 results in elevated expression of specific PKC isoforms and in enhanced generation of cellular DAG, and the latter appears to arise largely from the hydrolysis of plasma membrane PC.

Nitric oxide exposure and sulfhydryl modulation alter L-arginine transport in cultured pulmonary artery endothelial cells.

The effect of nitric oxide (NO) exposure and sulfhydryl-reactive chemicals on L-arginine transport in pulmonary artery endothelial cells was evaluated. Exposure of pulmonary artery endothelial cells to 7.5 ppm (0.4 microM) NO for 4 h resulted in a significant (p < 0.05) reduction of Na(+)-dependent but not Na(+)-independent L-arginine transport. More prolonged exposure for 12-24 h reduced both Na(+)-dependent and Na(+)-independent transport of L-arginine with maximal loss of transport after 18 h of exposure (p < 0.02 for both). Similarly, incubation of cells in the presence of 50-200 microM S-nitroso-acetyl-penicillamine (SNAP) (but not 500 microM each of nitrate or nitrite) for 2 h also reduced both the Na(+)-dependent and Na(+)-independent transport of L-arginine (p < 0.05 for all concentrations). The SNAP-induced reduction of L-arginine transport was blocked by the NO scavenger oxyhemoglobin. When cell monolayers were exposed to varying concentrations of the sulfhydryl reactive chemicals N-ethylmaleimide (NEM) and acrolein, a dose-dependent reduction of L-arginine transport by both Na(+)-dependent and Na(+)-independent processes was observed. Na(+)-dependent L-arginine transport was more susceptible to inhibition by exposure to NO and to sulfhydryl reactive chemicals. Incubation of cells with 0.5 mM of the thiol-containing agent N-acetyl-L-cysteine prior to and during NEM or acrolein exposure blocked NEM and acrolein-induced reduction of L-arginine transport by both Na(+)-dependent and Na(+)-independent processes. Similarly, NO-induced reductions of Na(+)-dependent and Na(+)-independent L-arginine transport were reversed to control levels 24 h after termination of NO exposure. Treatment with the disulfide reducing agent dithiothreitol after exposure to NO resulted in partial reversal of the decreases in L-arginine transport. These results demonstrate that exposure to exogenous NO is responsible for reversible reductions of plasma membrane-dependent L-arginine transport mediated by both the Na(+)-dependent (system Bo,+) and the Na(+)-independent (system y+) transport processes. Modulation of the sulfhydryl status of plasma membrane proteins involved in L-arginine transport, such as L-arginine transporters and/or Na+/K(+)-ATPase, may be responsible, at least in part, for reductions in overall L-arginine transport in pulmonary artery endothelial cells.

CD4+ T cell enumeration in HIV infection with limited resources.

The incidence of human immunodeficiency virus (HIV) infection continues to increase in South Africa. Limited resources are available for diagnosis and management of the disease and the development of affordable strategies is required. Absolute CD4 counts are used locally predominantly to monitor disease progression and institute prophylaxis against opportunistic infections. A dramatic increase in demand for CD4 counts prompted an investigation for a more cost-effective flow cytometry method than those currently recommended by the Centers for Disease Control (CDC). CD4 counts generated by two different single tube methods using CD3/CD4/CD8 [1(3)] and CD4 [1(1)] antibodies, respectively, were compared to the CDC recommended 6 tube 2 colour panel [6(2)]. Whole blood analysis using the Coulter Multi-Q-Prep system and an Epics XL Flow Cytometer (Coulter, Hialeah, FL) was performed for each of the three methods. Random samples from HIV positive adult patients were compared. A mean difference in the absolute CD4 counts of less than 10x10(6)/l was generated by both of the alternative panels when compared with the 6(2) panel. The precision of the three methods is comparable. In reagents alone, the 1(3) and 1(1) methods represent a cost saving of 76% and 93%, respectively, over the 6(2) method. The 1(3) and 1(1) panels would permit more affordable CD4 counts to be determined by the gold standard methodology of flow cytometry with no clinically significant sacrifices in accuracy or precision.

Effect of nitrogen dioxide on surface membrane fluidity and insulin receptor binding of pulmonary endothelial cells.

Nitrogen dioxide (NO2), an environmental oxidant pollutant, is known to peroxidize membrane lipids of lung cells. We evaluated the ability of NO2 to alter the surface membrane fluidity, lipid composition, and insulin receptor binding of porcine pulmonary artery endothelial cells in culture. After 3- to 24-hr exposure to 5 ppm NO2, cells were labeled with either 1-(4-trimethylaminophenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH), a cationic fluorescent aromatic hydrocarbon that anchors at the lipid-water interface, or fluorescamine, a fluorescent molecular probe that covalently binds with amino groups of surface phospholipids and proteins. Membrane fluidity was measured by monitoring changes in the steady-state fluorescence anisotropies (rs) for TMA-DPH and fluorescamine. Insulin specific receptor binding was monitored by measuring time-dependent binding of 125I-insulin. Following NO2 exposure, rs values for TMA-DPH and fluorescamine were increased significantly in a time-dependent fashion, with maximum increases at 24 hr (P less than 0.001). Similar increases in rs values were observed in isolated plasma membranes as well as in lipid vesicles prepared from total lipid extracts of endothelial cells or their plasma membranes. Phosphatidylethanolamine plus phosphatidylserine content in lipid extracts from 24-hr but not 3- to 12-hr NO2-exposed cells was increased significantly (P less than 0.01) compared to control cells. Specific binding of 125I-insulin to cells exposed to NO2 for 12 and 24 hr (but not 3 and 6 hr) was reduced significantly (P less than 0.05) compared to binding in control cells. Scatchard analysis of the binding data indicated that NO2 exposure caused a 5-fold reduction in insulin receptor binding sites in endothelial cells. Recovery was achieved 24 hr after NO2 exposure with, but not without, changing culture medium. These results indicate that NO2 exposure causes reversible changes in the physical state of lipids in the superficial lipid domains of the pulmonary endothelial cell plasma membrane, and these alterations may interfere with plasma membrane-dependent functions such as receptor-ligand interaction.

Hyperoxia reduces plasma membrane fluidity: a mechanism for endothelial cell dysfunction.

To evaluate the relative contributions of three possible mechanisms that can be advanced to explain the observation that hyperoxia decreases serotonin uptake by endothelial cells, we examined the effect of high O2 tensions on Na+-K+-ATPase activity, ATP content, and plasma membrane fluidity in cultured endothelial cells. Confluent monolayers of pulmonary artery and aortic endothelial cells were exposed to 95% O2 (hyperoxia) or 20% O2 (controls) in 5% CO2 at 1 ATA for 4-42 h. Exposure to high O2 tensions had no effect on Na+-K+-ATPase activity or ATP content in pulmonary artery or aortic endothelial cells in culture. However, hyperoxia decreased the fluidity of the plasma membrane of pulmonary artery and aortic endothelial cells in culture, and the time course for the decrease in fluidity parallels that of the hyperoxic inhibition of serotonin transport. These results indicate that hyperoxia decreases fluidity in the hydrophobic core of the plasma membranes of cultured endothelial cells. Such decreases in plasma membrane fluidity may be responsible for hyperoxia-induced alterations in membrane function including decreases in transmembrane transport of amines.

Ultrasonic prediction of fetal macrosomia in diabetic patients.

Traumatic morbidity in the newborn of a diabetic mother occurs in 3 to 9% of vaginal deliveries in diabetic pregnancies. Prediction of diabetic macrosomia by ultrasound measurement of chest diameter and biparietal diameter is evaluated in this study. A macrosomia index was calculated for 70 diabetic pregnancies by subtracting the biparietal diameter from the chest diameter (chest - biparietal diameter). Twenty-three macrosomic infants (weight greater than 4000 g) were delivered. In this study 20/23 (87%) of the infants weighing greater than 4000 g had a chest - biparietal diameter of 1.4 cm or greater. There were 4 cases of shoulder dystocia in 15 patients delivered vaginally. In this study, cesarean section for all fetuses with a chest - biparietal diameter of 1.4 cm or greater would reduce the incidence of traumatic morbidity from 27% to 9%.

Stimulation of cyclophosphamide-induced pulmonary microsomal lipid peroxidation by oxygen.

Cyclophosphamide (CP) causes lung toxicity in a wide variety of animals including humans. Recent reports suggest that CP increases lipid peroxide formation in the lung, and that oxygen (O2) potentiates CP-induced lung toxicity. We hypothesized that CP, or one of its toxic metabolites, acrolein, stimulates lung lipid peroxide formation in the presence of high O2 tensions. To test this, rat lung microsomes were treated in vitro with CP or acrolein in the presence of NADPH and 0-100% O2 with and without superoxide dismutase (SOD), glutathione (GSH), dithiothreitol (DTT), and EDTA (agents which scavenge reactive O2 species and/or detoxify reactive metabolites). Lipid peroxide formation in untreated microsomes was increased 40, 39, and 37% in 60, 80 and 100% O2 respectively (P less than 0.02 vs. 21% O2 air). Lipid peroxide formation in microsomes treated with CP increased 2-3-fold under 21% O2 (P less than 0.05 vs. untreated under 21% O2). However, increases in lipid peroxide formation were 3-4 fold in CP treated microsomes under 40-100% O2 (P less than 0.001 vs. untreated at same % O2). CP and acrolein-stimulated lipid peroxidation with and without O2 exposure was significantly (P less than 0.05) reduced by prior addition of SOD, GSH, DTT, or EDTA to the lung microsomal suspension. These results indicate that lipid peroxide formation increases in CP and acrolein-treated lung microsomes, and high O2 tensions stimulate CP-induced lipid peroxidation. Stimulation of CP-induced microsomal lipid peroxidation appears to be mediated by reactive O2 species or metabolites.