Evaluating Clinical Outcomes in Patients Being Treated Exclusively via Telepsychiatry: Retrospective Data Analysis

BACKGROUND

Depression and anxiety are highly prevalent conditions in the United States. Despite the availability of suitable therapeutic options, limited access to high-quality psychiatrists represents a major barrier to treatment. Although telepsychiatry has the potential to improve access to psychiatrists, treatment efficacy in the telepsychiatry model remains unclear.

OBJECTIVE

Our primary objective was to determine whether there was a clinically meaningful change in 1 of 2 validated outcome measures of depression and anxiety-the Patient Health Questionnaire-8 (PHQ-8) or the Generalized Anxiety Disorder-7 (GAD-7)-after receiving at least 8 weeks of treatment in an outpatient telepsychiatry setting.

METHODS

We included treatment-seeking patients enrolled in a large outpatient telepsychiatry service that accepts commercial insurance. All analyzed patients completed the GAD-7 and PHQ-8 prior to their first appointment and at least once after 8 weeks of treatment. Treatments included comprehensive diagnostic evaluation, supportive psychotherapy, and medication management.

RESULTS

In total, 1826 treatment-seeking patients were evaluated for clinically meaningful changes in GAD-7 and PHQ-8 scores during treatment. Mean treatment duration was 103 (SD 34) days. At baseline, 58.8% (1074/1826) and 60.1% (1097/1826) of patients exhibited at least moderate anxiety and depression, respectively. In response to treatment, mean change for GAD-7 was -6.71 (95% CI -7.03 to -6.40) and for PHQ-8 was -6.85 (95% CI -7.18 to -6.52). Patients with at least moderate symptoms at baseline showed a 45.7% reduction in GAD-7 scores and a 43.1% reduction in PHQ-8 scores. Effect sizes for GAD-7 and PHQ-8, as measured by Cohen d for paired samples, were d=1.30 (P<.001) and d=1.23 (P<.001), respectively. Changes in GAD-7 and PHQ-8 scores correlated with the type of insurance held by the patients. Greatest reductions in scores were observed among patients with commercial insurance (45% and 43.9% reductions in GAD-7 and PHQ-8 scores, respectively). Although patients with Medicare did exhibit statistically significant reductions in GAD-7 and PHQ-8 scores from baseline (P<.001), these improvements were attenuated compared to those in patients with commercial insurance (29.2% and 27.6% reduction in GAD-7 and PHQ-8 scores, respectively). Pairwise comparison tests revealed significant differences in treatment responses in patients with Medicare versus commercial insurance (P<.001). Responses were independent of patient geographic classification (urban vs rural; P=.48 for GAD-7 and P=.07 for PHQ-8). The finding that treatment efficacy was comparable among rural and urban patients indicated that telepsychiatry is a promising approach to overcome treatment disparities that stem from geographical constraints.

CONCLUSIONS

In this large retrospective data analysis of treatment-seeking patients using a telepsychiatry platform, we found robust and clinically significant improvement in depression and anxiety symptoms during treatment. The results provide further evidence that telepsychiatry is highly effective and has the potential to improve access to psychiatric care.

QUALITY OF LIFE IN BREAST CANCER SURVIVORS: AN ASSESSMENT OF INTERNATIONAL BREAST CANCER DRAGON BOAT RACERS

Resistance exercise is deemed safe for women recovering from conventional breast cancer therapies but few clinicians are aware that dragon boat racing, as a form of resistive exercise, is available to the breast cancer community. The objectives of this study were to 1) increase clinician awareness of dragon boat racing (DBR) in breast cancer survivors as a community-based physical activity, and 2) evaluate quality of life (QOL) in breast cancer survivors with or without lymphedema who participate in DBR. This prospective, observational study surveyed 1,069 international breast cancer dragon boat racers from eight countries to compare function, activity, and participation in women with and without self-reported lymphedema using the Lymph-ICF questionnaire. Seventy-one percent of women (n=758) completed the questionnaires. Results revealed significantly higher Lymph-ICF scores in the lymphedema participants, signifying reduced QOL, when compared to the nonlymphedema participants (p&lt;0.05), except for "go on vacation" for which no statistical difference was reported (p=0.20). International breast cancer survivors with lymphedema participating in DBR at an international competition had reduced function, limited activity, and restricted participation compared to participants without lymphedema. Clinicians should consider utilizing DBR as a community-based activity to support exercise and physical activity after a breast cancer diagnosis.

Quality of life in breast cancer survivors: An assessment of international breast cancer dragon boat racers

Resistance exercise is deemed safe for women recovering from conventional breast cancer therapies but few clinicians are aware that dragon boat racing, as a form of resistive exercise, is available to the breast cancer community. The objectives of this study were to 1) increase clinician awareness of dragon boat racing (DBR) in breast cancer survivors as a community-based physical activity, and 2) evaluate quality of life (QOL) in breast cancer survivors with or without lymphedema who participate in DBR. This prospective, observational study surveyed 1,069 international breast cancer dragon boat racers from eight countries to compare function, activity, and participation in women with and without selfreported lymphedema using the Lymph-ICF questionnaire. Seventy-one percent of women (n=758) completed the questionnaires. Results revealed significantly higher Lymph-ICF scores in the lymphedema participants, signifying reduced QOL, when compared to the nonlymphedema participants (p<0.05), except for "go on vacation" for which no statistical difference was reported (p=0.20). International breast cancer survivors with lymphedema participating in DBR at an international competition had reduced function, limited activity, and restricted participation compared to participants without lymphedema. Clinicians should consider utilizing DBR as a community-based activity to support exercise and physical activity after a breast cancer diagnosis.

Impaired Odor Perception in Autism Spectrum Disorder Is Associated with Decreased Activity in Olfactory Cortex

Autism Spectrum Disorders (ASDs) are characterized by atypical sensory functioning in the visual, tactile, and auditory systems. Although less explored, olfactory changes have been reported in ASD patients. To explore these changes on a neural level, 18 adults with ASD and 18 healthy neurotypical controls were examined in a 2-phase study. Participants were first tested for odor threshold and odor identification. Then, (i) structural magnetic resonance (MR) images of the olfactory bulb were acquired, and (ii) a functional MR imaging olfaction study was conducted. ASD patients exhibited decreased function for odor thresholds and odor identification; this was accompanied by a relatively decreased activation in the piriform cortex. In conclusion, these findings suggest, that the known alterations in olfaction in ASD are rooted in the primary olfactory cortex.

Direct thermo-optical tuning of silicon microresonators for the mid-infrared

We use light from a visible laser diode to directly tune silicon-on-chip microresonators by thermo-optical effect. We show that this direct tuning is local, non invasive and has a much smaller time constant than global temperature tuning methods. Such an approach could prove to be highly effective for Kerr comb generation in microresonators pumped by quantum cascade lasers, which cannot be easily tuned to achieve comb generation and soliton-mode locked states.

New records of angular rough sharks Oxynotus centrina in the coastal waters of Malta, with observations on post-capture resilience and release behaviour

One male and one female angular rough sharks Oxynotus centrina were caught south-east of Malta between May and June at a depth of 60-100 m < 5 km from shore. The immature female (total length, L_T 565 mm) was landed dead but the male (535 mm L_T ) was found alive. This communication presents important biological observations on post-capture recovery and release behaviour of this species.

The modulation of chlamydial replication by HLA-B27 depends on the cytoplasmic domain of HLA-B27

OBJECTIVE

The intracellular persistence of viable Chlamydia trachomatis (CT) within the joint is thought to initiate and maintain the inflammatory process in CT-induced arthritis. CT-induced arthritis is associated with HLA-B27. Recently it was shown that HLA-B27, besides being a T-cell restriction element, can directly influence the invasion and/or replication of enterobacteriae and alters salmonella-induced signal transduction. It was the aim of this study to analyze the effect of HLA-B27 on CT-invasion and replication in human host cells.

METHODS

Human Hela cells and Hela cells transfected with either HLA-B27 cDNA or controls (HLA-A1 cDNA; HLA-B27 mutant = HLA-B27 without cytoplasmic tail; B27Q10 = HLA-B27 Exon 1-4 linked to Exon 5 of murine Q10) were infected with CT. By direct immunofluorescence chlamydial invasion was determined 4 hours post infection (p.i.), chlamydial replication 2 days and 4 days p.i. The number of infective CT in the different cell lines was determined by titration of the cell lysates on Hep-2 cells with subsequent immunoperoxidase staining.

RESULTS

Invasion was not affected by HLA-B27. However, formation of chlamydial inclusion bodies and replication was suppressed by HLA-B27. Genetically engineered mutants of HLA-B27 (HLA-B27 mutant, B27Q10) lacking the cytoplasmic tail of HLA-B27 did not affect replication.

CONCLUSION

The reduction of chlamydial replication by HLA-B27 depends on the cytoplasmic domain of HLA-B27, thus providing a new hypothesis for chlamydial persistence in HLA-B27 positive reactive arthritis.

Prospective double-blind randomised study of a new regimen of pre-emptive analgesia for inguinal hernia repair: evaluation of postoperative pain course

OBJECTIVE

To evaluate the effectiveness of a new regimen of pre-emptive analgesia on the development of postoperative pain after inguinal hernia repair.

DESIGN

Prospective, double-blind, randomised study.

SETTING

University Hospital, Germany.

SUBJECTS

70 consecutive patients who had primary unilateral inguinal hernia repairs.

INTERVENTIONS

A new regimen of pre-emptive analgesia with bupivacaine that was infiltrated preoperatively, intraoperatively, and postoperatively was tested. The control group were given saline infiltrations at the same times. Pain was measured up to postoperative day 30 using the visual analogue scale (VAS), the verbal rating scale (VRS), and by recording patient-controlled use of ibuprofen suppositories.

RESULTS

Pain was significantly less in the pre-emptive analgesia group than in the control group during the first 10 days postoperatively as assessed by VAS and VRS (p < 0.05). Analgesic consumption was also significantly reduced in the pre-emptive analgesia group (p < 0.05). Multivariate analysis showed that bupivacaine infiltration (pre-emptive analgesia) was associated with significantly less postoperative pain (p < 0.0001).

CONCLUSION

This regimen of pre-emptive analgesia is an effective and safe method of reducing postoperative pain and analgesic consumption after inguinal hernia repair.

Optimised sample preparation of synovial fluid for detection of Chlamydia trachomatis DNA by polymerase chain reaction

OBJECTIVE

To optimise sample preparation of synovial fluid for Chlamydia trachomatis (CT) specific polymerase chain reaction (PCR).

METHODS

Serial dilutions of purified CT elementary bodies in synovial fluid were prepared. The synovial fluid pellet was processed by eight different methods of sample preparation. Then samples were analysed by CT specific PCR. The sensitivity of PCR was the basis of ranking of the eight different methods.

RESULTS

Highest sensitivity was achieved by methods including an additional step of DNA isolation. Additional extraction of protein and polysaccharides by cetyltrimethylammonium bromide (CTAB) increased sensitivity. Addition of hyaluronidase did not increase sensitivity of QIAEX-DNA extraction but was necessary, however, before phenol-chloroform-DNA extraction.

CONCLUSIONS

The method of synovial fluid sample preparation significantly influences the sensitivity of subsequent PCR. Additional DNA isolation and extraction of PCR inhibitors by CTAB led to higher sensitivity.

Reliability of taurine concentrations measured in single urine samples obtained from dogs eight hours after eating

OBJECTIVE

To evaluate the reliability of taurine concentrations measured in a single urine sample obtained from dogs 8 hours after eating, compared with taurine concentrations measured in 24-hour urine samples.

ANIMALS

18 healthy Beagles.

PROCEDURE

After emptying the urinary bladder by transurethral catheterization, dogs were fed a canned maintenance diet. Approximately 8 hours later, urine, plasma, and serum samples were obtained for determination of fractional urinary excretion of taurine and urine taurine-to-creatinine concentration ratios (Utaur:Ucr). Results were compared with 24-hour urinary taurine excretion rate.

RESULTS

Unbound and total fractional urinary taurine excretion correlated well with unbound and total 24-hour urinary taurine excretion. However, bound fractional urinary taurine excretion correlated poorly with bound 24-hour urinary taurine excretion. Unbound and total Utaur:Ucr correlated well with unbound and total 24-hour urinary taurine excretion. However, bound Utaur:Ucr correlated poorly with bound 24-hour urinary taurine excretion.

CONCLUSION AND CLINICAL RELEVANCE

Fractional urinary excretion of unbound and total taurine, and unbound and total Utaur:Ucr are reliable indicators of 24-hour urinary unbound and total taurine excretion in healthy dogs. However, determination of 24-hour urinary taurine excretion is recommended for evaluating urinary bound taurine concentrations of dogs.

Aetiological agents: their molecular biology and phagocyte-host interaction

Inflammatory joint disease can develop following an extra-articular infection. The term reactive arthritis was coined in order to differentiate this arthritis, which is often characterized by lack of culturable organisms in the joint, from septic arthritides. Bacteria known to trigger reactive arthritis include Campylobacter, Chlamydia, Salmonella, Shigella and Yersinia. Demonstration of bacteria or bacterial macromolecules in the joint has elicited the idea that reactive arthritis is a sterile process induced and maintained by antigenic material in the synovium. Continued synthesis of antigens to maintain synovial inflammation probably requires establishment of persistent bacterial infection in the joint, or at the primary site of infection. In the case of Chlamydia trachomatis, viable, metabolically-active organisms have been demonstrated to exist for extended periods in the joints of patients with reactive arthritis. In this chapter, we review the aetiological agents, and their molecular biology and phagocyte-host interactions, that are involved in reactive arthritis and spondylarthropathy.

Evaluation of the morphologic characteristics and prevalence of canine urocystoliths from a regional urolith center

OBJECTIVE

To determine whether morphology of single-mineral urocystoliths and age, sex, or breed data could be applied to facilitate radiographic and clinical urocystolith mineral type prediction, respectively, in dogs.

SAMPLE POPULATION

Database of 2,041 dogs with pure mineral composition urocystoliths.

PROCEDURE

All uroliths were characterized according to geologic descriptive terminology and by breed, sex, and age of dog at time of sample submission. Summary statistics were used to compare features with specific mineral types. Observed trends were analyzed for statistical relevance between observed and expected frequencies for age, sex, color, size, shape, and surface, using the null hypothesis that differences by urocystolith mineral type did not exist. On the basis of expected breed occurrence derived by equations, the null hypothesis that urocystolith occurrence paralleled canine breed popularity was tested.

RESULTS

Urocystoliths > 10 mm in any dimension were > 92% likely to be magnesium ammonium phosphate hexahydrate (MAP). Smooth, blunt-edged or faceted, and pyramidal urocystoliths were usually MAP. Jackstone shapes were almost always silica. Botryoidal (grape-like clusters) urocystoliths were likely to be oxalates. Breeds with high relative likelihood of urocystoliths included: English Bulldog, Pekingese, Pug, Welsh Corgi, and West Highland White Terrier. Breeds with low relative likelihood of urocystolith production included: German Shepherd Dog, Shar-Pei, and German Shorthaired Pointer. About 94% of urocystoliths produced in females or spayed females were MAP, whereas males and neutered males produced a greater assortment.

CONCLUSIONS AND CLINICAL RELEVANCE

For pure mineral composition urocystoliths, trends in mineral type among breeds and between sexes can be exploited clinically in the diagnosis and management of urolith-related disease. Size and shape, used in conjunction with age, breed, and sex, can facilitate pure urocystolith mineral type prediction.

Ultrastructural and molecular analyses of the persistence of Chlamydia trachomatis (serovar K) in human monocytes

Previous studies have suggested that monocytes may play a role in the dissemination of Chlamydia trachomatis, and in establishment of persistent infection with this bacterium. Infection of cultured human peripheral blood monocytes with C. trachomatis serovar K produced persistent, nonproductive infection. Transmission electron microscopy of such infected cultures revealed single or multiple Chlamydia in monocyte inclusions over a culture period of 10 days. Those inclusions were aberrant, and normal reticulate bodies within the inclusions were not observed. Immunoelectron microscopy showed the chlamydial major outer membrane protein and lipopolysaccharide to be associated with the bacterial plasma membrane. Lipopolysaccharide was also identified in the monocyte cytoplasm. Molecular analyses of primary chlamydial rRNA transcripts demonstrated that the organism is viable and metabolically active within monocyte inclusions. However, attempts to overcome chlamydial growth arrest by incubation of Chlamydia-infected monocytes with tryptophan, and antibodies against alpha interferon, gamma interferon, or tumor necrosis factor, were all ineffective, suggesting that known mechanisms of growth inhibition do not hold in human monocytes. These observations indicate that infection of human peripheral blood monocytes with C. trachomatis may be involved in the genesis/maintenance of extra-urogenital inflammation, since non-culturable, metabolically active bacteria persist in those cells.

Reliability of carnitine concentrations measured in single postprandial urine samples from dogs

OBJECTIVE

To evaluate the reliability of urine carnitine concentrations measured in single postprandial samples, compared with carnitine concentrations measured in 24-hour urine samples.

ANIMALS

19 healthy Beagles.

PROCEDURE

After emptying the urinary bladder by catheterization, dogs were fed a canned canine maintenance diet. Approximately 8 hours later, urine, plasma, and serum samples were obtained for determination of urinary carnitine fractional excretion and urine carnitine-to-creatinine concentration ratio. Results were compared with 24-hour urinary carnitine excretion rate.

RESULTS

Fractional excretion of carnitine and urine carnitine-to-creatinine ratios correlated poorly with 24-hour urinary carnitine excretion.

CONCLUSION

Determination of 24-hour urinary carnitine excretion is recommended to measure urine carnitine concentrations in dogs.

Influence of two amounts of dietary casein on uric acid, sodium urate, and ammonium urate urinary activity product ratios of healthy beagles

Casein has been used as a protein source in diets designed to dissolve canine ammonium urate uroliths and to prevent their recurrence, because it contains fewer purine precursors than do many other sources of protein. However, an important question is whether reduced quantities of dietary casein have any benefit in modifying saturation of urine with urates. To answer this question, activity product ratios of uric acid, sodium urate, and ammonium urate were determined in 24-hour urine samples produced by 6 healthy Beagles during periods of consumption of a 10.4% protein, casein-based (10.4% casein) diet and a 20.8% protein, casein-based (20.8%casein) diet. Significantly lower 24-hour urinary excretions of ammonia and phosphorus were observed when dogs consumed the 10.4% casein diet. These results suggest that use of the 10.4% casein diet in protocols designed for dissolution and prevention of uric acid, sodium urate, and ammonium urate uroliths in dogs may be beneficial.

Spermatozoal ultrastructure in three species of parrots (aves, Psittaciformes) and its phylogenetic implications

BACKGROUND

DNA-DNA hybridization studies suggest that Psittaciformes are highly, but not the most, derived nonpasserines. Multilocus protein electrophoresis indicates that cockatoos (Cacatuinae) form a monophyletic lineage distant from the other Australo-Papuan psittacids (Psittacinae).

METHODS

Transmission electron microscope procedures are applied to the spermatozoa of three parrots, in the Cacatuninae and Psittacinae, to investigate these relationships.

RESULTS

Psittaciform sperm have the following characteristics: (1) conical acrosome vesicle; rodlike perforatorium; cylindrical, highly condensed nucleus; proximal and distal centriole embedded in dense material; elongate periaxonemal mitochondrial midpiece, (2) nine dense peripheral axonemal fibers (coarse fibers), (3) no fibrous sheath around the axoneme, (4) mitochondria with linear cristae, lacking intra- (or inter-) mitochondrial dense bodies, (5) restriction of the endonuclear perforatorial canal to the anterior region of the nucleus, (6) a short distal centriole, and (7) nucleus abutting on but not penetrating the acrosome.

CONCLUSIONS

(1) These features are tetrapod symplesiomorphies, (2) is an amniote synapomorphy; the fibers differ from those of reptiles in being uniform in size, (3) loss of the fibrous sheath is an apomorphy known elsewhere only in columbiforms, (4) are apomorphies relative to basal aminiotes (Chelonia, Sphenodon, and Crocodilia), (5) is an apomorphic condition shared with other nonpasserines (galliforms and the white-naped crane) and crocodilians, (6) the latter taxa differ from parrots in a plesiomorphic elongation of the distal centriole, and (7) is a unique apomorphy of parrot sperm relative to other nonpasserines and reptiles. The short midpiece of N. hollandicus distinguishes this cacatuine from the two psittacines.

The ultrastructure of the spermatozoon of the northern water snake, Nerodia sipedon (Colubridae, Serpentes), with phylogenetic considerations

The ultrastructure of the spermatozoon of Nerodia sipedon conforms closely to that of other described snake sperm: it is filiform; the acrosome vesicle is in the form of a hollow, concentrically zoned cone that basally overlies a subacrosomal cone which invests the tapered anterior end of the nucleus; the putative perforatorium is a slender rod extending anteriorly from the subacrosomal cone; the midpiece contains dense bodies and mitochondria; the axonemal fibrous sheath extends anteriorly into the midpiece (squamate autapomorphy); 9 peripheral dense fibres surround the distal centriole and the axoneme in the midpiece, of which fibres adjacent to 3 and 8 are enlarged; and the endpiece lacks peripheral fibres and the fibrous sheath. The midpiece is very long (a synapomorphy of the Serpentes) and is surrounded by a multilaminar membrane (an autapomorphy). In the squamates, only snakes, including N. sipedon, retain microtubules external to the plasma membrane of the mature spermatozoon. Helically arranged zigzag mitochondria are shared (probably homoplasically) with iguanid sperm. A poorly developed "stopperlike" putative perforatorial base plate in N. sipedon, unknown in other snakes, is questionably homologous with that of gekkonids. An electron-lucent space caps the nuclear point, as in the snakes Boiga irregularis and Stegonotus cucullatus and in some other squamate orders.

Glucocorticoid-induced reduction of prostanoid synthesis in TPA-differentiated U937 cells is mainly due to a reduced cyclooxygenase activity

The molecular mechanism of the glucocorticoid-induced inhibition of prostanoid synthesis was investigated in human monoblastoid U937 tumor cells and phorbol ester (TPA)-differentiated U937 cells. Prostanoid synthesis was inhibited in TPA-differentiated U937 cells by glucocorticoids such as dexamethasone and prednisolone, whereas aldosterone and progesterone showed no inhibitory effect. None of these methods had any influence on prostanoid secretion of undifferentiated U937 cells. Receptor binding studies revealed the presence of glucocorticoid receptors in both undifferentiated and TPA-differentiated U937 cells (Kp approximately 5 x 10(-9)M), however, the number of receptors per cell was increased 10-fold in TPA-differentiated U937 cells. Expression of lipocortin I and II as measured by Western blot analysis was not affected by dexamethasone. In TPA-differentiated cells, dexamethasone decreased the activities of two enzymes essential for prostanoid synthesis, cyclooxygenase and phospholipase A2, by 60-70% and 30%, respectively. Cells pretreated with the translation inhibitor cyclohexmide and dexamethasone showed similar cyclooxygenase and phospholipase A2 activities as cells treated with cycloheximide alone. Western blot analysis demonstrated that the significantly decreased cyclooxygenase activity correlated with an inhibited protein synthesis. In this human macrophage-like model glucocorticoids thus interfere at least at two levels with prostanoid synthesis by inhibiting the activities of phospholipase A2 as well as cyclooxygenase.

The effects of recoding and presentation format on recency and suffix effects

The primary linguistic theory of Shand and Klima (1981) hypothesizes that stimuli that cannot be directly processed without recoding are not in the primary linguistic mode of the subject and thus should lead to lesser recency and associated suffix effects. In three experiments, different normal hearing subjects learned to pair American Sign Language (ASL) stimuli, visual "quasivocables" (QVs), word-like letter strings, and auditory QVs with common English words. In the first experiment, the subjects were given sequences of ASL or QV stimuli and required to recall the associated words in strict serial order. In two other experiments involving auditory and visual presentation, respectively, subjects who had never been given paired associate training were required to recall the English words that had previously been associated with the ASL and QV stimuli, in a standard suffix paradigm. The results showed recency and suffix effects to be present only with auditorily presented QVs and words. Contrary to the predictions of the primary linguistic hypothesis, greater recency and larger suffix effects were present with the auditory QVs than with the auditory words, although the QVs were not primary linguistic and the task involved forced recoding. Previous results showing recency with ASL stimuli in normal subjects were not replicated. It is concluded that recency and suffix effects are not related either to the primary linguistic mode of the subject or to stimulus recoding, as we and Shand and Klima have defined them.

Altered arachidonic acid metabolism during differentiation of the human monoblastoid cell line U937

The human cell line U937 was used as a model for differentiation along the mononuclear phagocyte lineage. Following treatment with the phorbol ester TPA, PGE2 and TxB2 secretion was induced 50-100-fold, and both PGF2 alpha and PGI2 levels became detectable in the supernatant of TPA-differentiated U937 cells. The content of the prostaglandin precursor, arachidonic acid, remained unchanged in the cellular phospholipids of undifferentiated and TPA-differentiated U937 cells. Of the enzymes involved in the availability and metabolism of arachidonic acid, phospholipase A2 activity was increased 2-fold in the membranes of TPA-differentiated U937 cells, whereas lysophosphatide acyltransferase activity remained unaltered. Cyclooxygenase activity, however, was enhanced 5-10-fold, which was due to enhanced expression of the enzyme as demonstrated by dot-blot analysis. The data suggest that the capacity to secrete prostaglandins is acquired during differentiation with TPA and results mainly from an increased cyclooxygenase activity. Despite the capacity of TPA-differentiated U937 cells to synthesize prostaglandins, none of the known monocytic stimuli further stimulated prostaglandin secretion in TPA-differentiated U937 cells. Generation of leukotrienes appears to represent a later state in the differentiation along the monocyte-macrophage lineage, since neither LTB4 nor cysteinyl-leukotrienes were detectable in the supernatants of either undifferentiated or TPA-differentiated U937 cells.

Differential effect of dexamethasone on the regulation of phospholipase A2 and prostanoid synthesis in undifferentiated and phorbolester-differentiated U937 cells

The human undifferentiated histiocytic cell-line U937 can be induced to differentiate by incubation with 12-0-tetradecanoylphorbol-13-acetate (TPA) into macrophage-like cells. Dexamethasone reduced the prostaglandin production in TPA-differentiated U937 cells dose dependently, whereas undifferentiated U937 cells were dexamethasone insensitive. Concomitantly phospholipase A2, the enzyme liberating the prostaglandin precursor arachidonic acid, was inhibited by dexamethasone in TPA-differentiated but not in undifferentiated U937 cells. The activity of lysophosphatide acyltransferase, the key enzyme of fatty acid reacylation into phospholipids, remained unchanged both in undifferentiated and TPA-differentiated U937 cells. The data suggest that responsiveness to glucocorticoid-dependent regulation of prostanoid synthesis is acquired by cells of the monocyte-macrophage lineage late in differentiation.

Airborne laser Doppler velocimeter

A CO(2) laser Doppler detection system has been developed to measure remotely the true airspeed of an aircraft. The system uses a 50-W sealed-off CO(2) laser in a homodyne detection system employing a collinear optical telescope, a HgCdTe detector, and a frequency tracking loop. The system was successfully flight tested on a NASA Convair 990 research aircraft during December 1971 and June 1972. The results indicate that an airspeed measurement under clear weather conditions is feasible up to an altitude of 3000 m with an error of less than 0.5%.