Visual Conformity With Affirmed Gender or "Passing": Its Distribution and Association With Depression and Anxiety in a Cohort of Transgender People

BACKGROUND

Visual conformity with affirmed gender (VCAG) or "passing" is thought to be an important, but poorly understood, determinant of well-being in transgender people. VCAG is a subjective measure that is different from having an inner sense of being congruent with one's gender identity.

AIM

We examined the frequency and determinants of VCAG and explored its association with mental health outcomes in a cohort of transgender adults.

METHODS

The "Study of Transition, Outcomes & Gender (STRONG)" is a cohort of transgender individuals recruited from 3 Kaiser Permanente health plans located in Georgia, Northern California and Southern California. A subset of cohort members completed a survey between 2015 and 2017. VCAG was assessed as the difference between 2 scales: scale 1 reflecting the person's sense of how they are perceived by others, and scale 2 reflecting the person's desire to be perceived. Participants were considered to have achieved VCAG when their scale 1 scores were equal to or exceeded their scale 2 scores. The frequency of VCAG and their independent associations with anxiety and depression symptoms were explored using data from 620 survey respondents including 309 transwomen and 311 transmen. Based on self-described gender identity, none of the participants identified as nonbinary or gender fluid.

OUTCOMES

VCAG, depression, and anxiety.

RESULTS

VCAG was achieved in 28% of transwomen and 62% of transmen and was more common in persons who reported greater sense of acceptance and pride in their gender identity as measured on the Transgender Congruence Scale. Another factor associated with greater likelihood of VCAG was receipt of gender-affirming surgery, but the association was only evident among transmen. Participants who achieved VCAG had a lower likelihood of depression and anxiety with prevalence ratios (95% confidence intervals) of 0.79 (0.65, 0.96) and 0.67 (0.46, 0.98), respectively.

CLINICAL IMPLICATIONS

VCAG may serve as an important outcome measure after gender-affirming therapy.

STRENGTHS AND LIMITATIONS

Strengths of this study include a well-defined sampling frame and use of a novel patient-centered outcome of interest. Cross-sectional design and uncertain generalizability of results are the limitations.

CONCLUSION

These results, once confirmed by prospective studies, may help better characterize the determinants of well-being in the transgender community, facilitating the design of interventions to improve the well-being and quality of life of this vulnerable population. To M, Zhang Q, Bradlyn A, et al. Visual Conformity With Affirmed Gender or "Passing": Its Distribution and Association With Depression and Anxiety in a Cohort of Transgender People. J Sex Med 2020;17:2084-2092.

Leucine-enriched essential amino acid supplementation in mechanically ventilated trauma patients: a feasibility study

Background

Critically ill patients lose up to 2% of muscle mass per day. We assessed the feasibility of administering a leucine-enriched essential amino acid (L-EAA) supplement to mechanically ventilated trauma patients with the aim of assessing the effect on skeletal muscle mass and function.

Methods

A randomised feasibility study was performed over six months in intensive care (ICU). Patients received 5 g L-EAA five times per day in addition to standard feed (L-EAA group) or standard feed only (control group) for up to 14 days. C-reactive protein, albumin, IL-6, IL-10, urinary 3-MH, nitrogen balance, protein turnover ([1-13C] leucine infusion), muscle depth change (ultrasound), functional change (Katz and Barthel indices) and muscle strength Medical Research Council (MRC) sum score to assess ICU Acquired Weakness were measured sequentially.

Results

Eight patients (9.5% of screened patients) were recruited over six months. L-EAA doses were provided on 91/124 (73%) occasions. Inflammatory and urinary marker data were collected; serial muscle depth measurements were lacking due to short length of stay. Protein turnover studies were performed on five occasions. MRC sum score could not be performed as patients were not able to respond to the screening questions. The Katz and Barthel indices did not change. L-EAA delivery was achievable, but meaningful functional and muscle mass outcome measures require careful consideration in the design of a future randomised controlled trial.

Conclusion

L-EAA was practical to provide, but we found significant barriers to recruitment and measurement of the chosen outcomes which would need to be addressed in the design of a future, large randomised controlled trial.

Trial registration

ISRCTN Registry, ISRCTN79066838. Registered on 25 July 2012.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3639-2) contains supplementary material, which is available to authorized users.

Cerclage for sonographic short cervix in singleton gestations without prior spontaneous preterm birth: systematic review and meta-analysis of randomized controlled trials using individual patient-level data

OBJECTIVE

The aim of this systematic review and meta-analysis was to quantify the efficacy of cervical cerclage in preventing preterm birth (PTB) in asymptomatic singleton pregnancies with a short mid-trimester cervical length (CL) on transvaginal sonography (TVS) and without prior spontaneous PTB.

METHODS

Electronic databases were searched from inception of each database until February 2017. No language restrictions were applied. All randomized controlled trials (RCTs) of asymptomatic singleton pregnancies without prior spontaneous PTB, found to have short CL < 25 mm on mid-trimester TVS and then randomized to management with either cerclage or no cerclage, were included. Corresponding authors of all the included trials were contacted to obtain access to the data and perform a meta-analysis of individual patient-level data. Data provided by the investigators were merged into a master database constructed specifically for the review. Primary outcome was PTB < 35 weeks. Summary measures were reported as relative risk (RR) with 95% CI. The quality of the evidence was assessed using the GRADE approach.

RESULTS

Five RCTs, including 419 asymptomatic singleton gestations with TVS-CL < 25 mm and without prior spontaneous PTB, were analyzed. In women who were randomized to the cerclage group compared with those in the control group, no statistically significant differences were found in PTB < 35 (21.9% vs 27.7%; RR, 0.88 (95% CI 0.63-1.23); I²  = 0%; five studies, 419 participants), < 34, < 32, < 28 and < 24 weeks, gestational age at delivery, preterm prelabor rupture of membranes (PPROM) and neonatal outcomes. In women who received cerclage compared with those who did not, planned subgroup analyses revealed a significantly lower rate of PTB < 35 weeks in women with TVS-CL < 10 mm (39.5% vs 58.0%; RR, 0.68 (95% CI, 0.47-0.98); I²  = 0%; five studies; 126 participants) and in women who received tocolytics (17.5% vs 32.7%; RR, 0.54 (95% CI, 0.31-0.93); I²  = 0%; four studies; 169 participants) or antibiotics (18.3% vs 31.5%; RR, 0.58 (95% CI, 0.33-0.98); I²  = 0%; three studies; 163 participants) as additional therapy to cerclage. The quality of evidence was downgraded two levels because of serious imprecision and indirectness, and therefore was judged as low.

CONCLUSIONS

In singleton gestations without prior spontaneous PTB but with TVS-CL < 25 mm in the second trimester, cerclage does not seem to prevent preterm delivery or improve neonatal outcome. However, in these pregnancies, cerclage seems to be efficacious at lower CLs, such as < 10 mm, and when tocolytics or antibiotics are used as additional therapy, requiring further studies in these subgroups. Given the low quality of evidence, further well-designed RCTs are needed to confirm the findings of this study. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

An alternative to a randomised control design for assessing the efficacy and effectiveness of bracing in adolescent idiopathic scoliosis

Randomised controlled trials (RCTs) that assessed the efficacy of bracing for adolescent idiopathic scoliosis have suffered from small sample sizes, low compliance and lack of willingness to participate. The aim of this study was to assess the feasibility of a comprehensive cohort study for evaluating both the efficacy and the effectiveness of bracing in patients with adolescent idiopathic scoliosis. Patients with curves at greater risk of progression were invited to join a randomised controlled trial. Those who declined were given the option to remain in the study and to choose whether they wished to be braced or observed. Of 87 eligible patients (5 boys and 63 girls) identified over one year, 68 (78%) with mean age of 12.5 years (10 to 15) consented to participate, with a mean follow-up of 168 weeks (0 to 290). Of these, 19 (28%) accepted randomisation. Of those who declined randomisation, 18 (37%) chose a brace. Patients who were more satisfied with their image were more likely to choose bracing (Odds Ratio 4.1; 95% confidence interval 1.1 to 15.0; p = 0.035). This comprehensive cohort study design facilitates the assessment of both efficacy and effectiveness of bracing in patients with adolescent idiopathic scoliosis, which is not feasible in a conventional randomised controlled trial.

Diabetes-induced morphological, biomechanical, and compositional changes in ocular basement membranes

The current study investigates the structural and compositional changes of ocular basement membranes (BMs) during long-term diabetes. By comparing retinal vascular BMs and the inner limiting membrane (ILM) from diabetic and non-diabetic human eyes by light and transmission electron microscopy (TEM), a massive, diabetes-related increase in the thickness of these BMs was detected. The increase in ILM thickness was confirmed by atomic force microscopy (AFM) on native ILM flat-mount preparations. AFM also detected a diabetes-induced increase in ILM stiffness. The changes in BM morphology and biophysical properties were accompanied by partial changes in the biochemical composition as shown by immunocytochemistry and western blots: agrin, fibronectin and tenascin underwent relative increases in concentration in diabetic BMs as compared to non-diabetic BMs. Fibronectin and tenascin were particularly high in the BMs of outlining microvascular aneurisms. The present data showed that retinal vascular BMs and the ILM undergo morphological, biomechanical and compositional changes during long-term diabetes. The increase in BM thickness not only resulted from an up-regulation of the standard BM proteins, but also from the expression of diabetes-specific extracellular matrix proteins that are not normally found in retinal BMs.

Summation of perceptual cues in natural visual scenes

Natural visual scenes are rich in information, and any neural system analysing them must piece together the many messages from large arrays of diverse feature detectors. It is known how threshold detection of compound visual stimuli (sinusoidal gratings) is determined by their components' thresholds. We investigate whether similar combination rules apply to the perception of the complex and suprathreshold visual elements in naturalistic visual images. Observers gave magnitude estimations (ratings) of the perceived differences between pairs of images made from photographs of natural scenes. Images in some pairs differed along one stimulus dimension such as object colour, location, size or blur. But, for other image pairs, there were composite differences along two dimensions (e.g. both colour and object-location might change). We examined whether the ratings for such composite pairs could be predicted from the two ratings for the respective pairs in which only one stimulus dimension had changed. We found a pooling relationship similar to that proposed for simple stimuli: Minkowski summation with exponent 2.84 yielded the best predictive power (r=0.96), an exponent similar to that generally reported for compound grating detection. This suggests that theories based on detecting simple stimuli can encompass visual processing of complex, suprathreshold stimuli.

Cervical length and obstetric history predict spontaneous preterm birth: development and validation of a model to provide individualized risk assessment

OBJECTIVES

To evaluate the ability of combinations of cervical length and maternal history to assess the risk of spontaneous preterm birth, and to provide a simple procedure for the optimal estimation of risk.

METHODS

This prospective observational study was carried out between January 1998 and May 2006. Transvaginal sonographic measurement of cervical length at 20 + 0 to 24 + 6 weeks of gestation was carried out in 58 807 singleton pregnancies as part of routine antenatal care. The outcome measure was spontaneous extreme (< 28 weeks), early (28-30 weeks), moderate (31-33 weeks) and mild (34-36 weeks) preterm birth. Logistic regression analysis was used to derive models for the prediction of spontaneous preterm birth from the maternal obstetric history, demographic characteristics and cervical length.

RESULTS

The rates of extreme, early, moderate and mild spontaneous preterm birth were 0.23%, 0.24%, 0.57% and 2.93%, respectively. The best prediction of spontaneous preterm birth was provided by cervical length (area under the receiver-operating characteristics curve (AUC), extreme 0.903, early 0.816, moderate 0.784 and mild 0.617) and this was improved by adding obstetric history (AUC, extreme 0.919, early 0.836, moderate 0.819 and mild 0.650). Addition of other parameters was without material effect. For a 10% screen-positive rate, models using cervical length and obstetric history had a sensitivity of 80.6%, 58.5%, 53.0% and 28.6% for extreme, early, moderate and mild spontaneous preterm birth, respectively. These models were expressed as tables of adjusted likelihood ratios to allow simple estimation of the risk of spontaneous preterm birth.

CONCLUSIONS

A model combining cervical length and obstetric history provides a better prediction of spontaneous preterm birth than either factor alone, and the sensitivity of screening improves for increasing degrees of prematurity.

Preterm birth: the value of sonographic measurement of cervical length

Transvaginal ultrasound scanning of cervical length at approximately 20 weeks of gestation in women attending for routine antenatal care is useful for predicting the likelihood of spontaneous early preterm birth. The risk of early birth increases exponentially with decreasing cervical length in both singleton and multiple pregnancies. In such women, individualization of risk would lead to rationalisation of antenatal care, including frequency of visits, patient education in recognising and reporting symptoms of spontaneous preterm labour and timely administration of steroids. It is also possible that in women identified as being at high risk, the rate of preterm birth might be reduced by the prophylactic use of progesterone. In women presenting with threatened spontaneous preterm labour, transvaginal measurement of cervical length provides a useful distinction between those who are likely to deliver within the subsequent 7 days and those who are not. Since only 10-20% of such women are in true spontaneous preterm labour, the cervical length measurement in rational care can avoid the current practice of hospitalisation and administration of steroids and tocolytics to all. This article reviews the evidence in support of the clinical introduction of transvaginal sonography for both the prediction and management of spontaneous preterm labour.

Transvaginal ultrasound in pregnancy: its acceptability to women and maternal psychological morbidity

OBJECTIVES

To assess the acceptability to women of antenatal transvaginal ultrasound scans; to compare the characteristics of women who accept the offer of a transvaginal scan with those who decline; to establish the prevalence of any psychological morbidity associated with the scan.

METHODS

The study was a cross-sectional questionnaire survey. Women were recruited from two hospitals in South London. The sample consisted of 755 pregnant women who had a transvaginal scan at 23 weeks' gestation to assess the risk of preterm delivery and 167 women who were offered the transvaginal scan but declined. Women completed a questionnaire at home. Those who reported finding the scan a difficult experience were sent a questionnaire 4 weeks post-scan to assess its longer term impact. The main outcomes were acceptability (assessed by individual questionnaire items); anxiety before and during the scan (Spielberger State-trait Anxiety Inventory); pain during the scan (Present Pain Intensity Scale of the McGill Pain Questionnaire); psychological trauma (Impact of Event Scale).

RESULTS

Over half (55.2%) of women accepted the offer of a transvaginal scan, according to hospital records. The majority of study participants who had transvaginal ultrasound reported finding the experience acceptable. Women experienced some anxiety before and during the scan and over a third experienced some (usually mild) pain during the procedure. Twelve women (1.6%) reported clinically significant levels of psychological trauma in relation to the scan.

CONCLUSIONS

Antenatal transvaginal ultrasound for assessing the risk of preterm delivery is an acceptable procedure for the majority of women. A significant minority decline the scan. The procedure has some psychological sequelae for some women.

Unexpected reduction in the incidence of birth trauma and birth asphyxia related to instrumental deliveries during the study period: was this the Hawthorne effect?

OBJECTIVE

The study was originally designed to identify the risk factors that could predict those difficult instrumental deliveries resulting in birth trauma and birth asphyxia.

DESIGN

A prospective study on all singleton deliveries in cephalic presentation with an attempt of instrumental delivery over a 12-month period (13 March 2000 to 12 March 2001).

SETTING

A local teaching hospital.

SAMPLE

Six hundred and seventy deliveries.

METHODS

A codesheet was designed to record the demographic data, characteristics of first and second stages of labour and neonatal outcome. In particular, the doctor had to enter the pelvic examination findings before the attempt of instrumental delivery.

MAIN OUTCOME MEASURES

Birth trauma and birth asphyxia.

RESULTS

There was a significant reduction in the incidence of birth trauma and birth asphyxia related to instrumental deliveries during the study period (0.6%) when compared with that (2.8%) in the pre-study period (1998 and 1999) (RR 0.27, 95% CI 0.11-0.70). There was more trial of instrumental deliveries in the operating theatre although this was not statistically significant (RR 1.19, 95% CI 0.88-1.60). The instrumental delivery rate decreased during the study period (RR 0.88, 95% CI 0.82-0.94). The caesarean section rate for no progress of labour, the incidence of direct second stage caesarean section and the incidence of failed instrumental delivery did not increase during the study period.

CONCLUSIONS

Apart from the merits of regular audit exercise and increasing experience of the staff, the Hawthorne effect might be the major contributing factor in the reduction of birth trauma and birth asphyxia related to instrumental deliveries during the study period.

[Successful therapy of cyclosporin A in a case with idiopathic interstitial pneumonia]

Seventy-one-year-old woman was visited to our hospital because of dry cough and dyspnea on effort. Fine crackle was audible on both lower lung fields. Joints and skin were normal. Laboratory examination revealed elevation of serum LDH and CRP level. Both anti-nuclear antibody and Jo-1 antibody were negative. Blood gas analysis showed hypoxia after exercise. Chest X-ray film showed reticular shadow in both lower lung fields. Chest CT finding showed patchy area of ground glass attenuation, air-space consolidation, and reticular shadow. Scintigram showed diffuse uptake of Gallium-67 in both lung. Transbronchial biopsy specimen revealed alveolar wall thickness, lymphocyte infiltration and swelling of type II pneumocytes. Bronchoalveolar lavage fluid analysis revealed elevation of CD4/CD8 ratio. She was given a diagnosis of idiopathic interstitial pneumonia. Combination therapy of cyclosporin A and steroid was performed. After therapy, her chest CT findings and her data of pulmonary function test were improved. Then therapy of cyclosporin A was continued and dose of prednisolone was gradually decreased. After that, she was suffered from respiratory tract infection. After administration of antibiotics and cyclosporin A, she was getting well without acute exacerbation of interstitial pneumonia. Since then, she was treated with cyclosporin A only and her pulmonary function test data were gradually improved more. It suggests that cyclosporin A may be useful for the treatment of idiopathic interstitial pneumonia.

[A case of idiopathic subglottic stenosis successfully treated with endoscopic laser treatment]

A 24-year-old woman presented with an abnormal sound in her neck. She had no history of previous surgery, endotracheal intubation or neck trauma. She had been aware of this abnormal sound since she was 12 years old, but paid no attention to it. She had been recommended to visit a hospital for a neck examination. Stridor was heared in the neck ["coming from the throat"?]. Peak flow was markedly suppressed in pulmonary function tests, and the flow volume loop indicated upper airway stenosis. Bronchoscopy revealed subglottic tracheal stenosis, and magnetic resonance imaging showed that the cricoid cartilage was normal. Nd-YAG laser treatment was performed in Mitsui Memorial Hospital and her symptoms were improved. Biopsy of the stenotic area of the trachea showed dense fibrous tissue proliferation in the submucosa. Neither granuloma nor vasculitis was found in the biopsy specimen. No systemic disease capable of inducing tracheal stenosis was found on systemic examination. From these clinical and pathological findings, we diagnosed idiopathic subglottic stenosis.

Delayed repair of transected nerves: effect of brain-derived neurotrophic factor

OBJECTIVE

To determine if administration of brain-derived neurotrophic factor (BDNF) after peripheral nerve transection can improve the functional outcome in situations where epineurial repair must be delayed.

DESIGN

Randomized, blinded, controlled trial.

SUBJECTS

Thirty-four Sprague-Dawley rats.

INTERVENTION

Sciatic nerves were transected and, after a 2-week delay, repaired with epineurial sutures. Animals were assigned to receive daily administration of lactated Ringer solution (LR [control] group); BDNF delivered at the time of nerve transection through 2 weeks after nerve repair, for a total of 4 weeks (BDNF-early group); or BDNF delivered at the time of nerve repair through 2 weeks after repair (BDNF-late group). Outcome was assessed using sciatic functional indices (SFIs) and histomorphometric analysis.

RESULTS

The SFI maximal recovery was superior in the BDNF groups, but this difference did not reach statistical significance (SFI, -90.1+/-9.6 [LR group], -85.7+/-7.6 [BDNF-early group], and -84.6+/-4.8 [BDNF-late group], where normal function is 0 and complete loss of function is -100; P = .27). The mean axon diameter tended to be greater in the BDNF groups compared with the LR group, i.e., 2.43+/-0.23 microm (LR group), 2.80+/-0.44 microm (BDNF-early group), and 2.83+/-0.38 microm (BDNF-late group) (P = .05).

CONCLUSIONS

The local administration of BDNF to nerves that underwent transection and then repair after a delay resulted in an increase in axonal diameters and maximal SFIs, a difference that did not reach statistical significance. The timing of BDNF administration after nerve transection did not affect neuronal regeneration.

[Immunohistochemical analysis of bronchial mucosa in severe asthmatics treated with long-term, high-dose inhaled BDP]

To analyze specific mucosal changes in asthmatic patients receiving long-term, high-dose beclomethazone dipropionate (BDP) inhalation therapy, we performed bronchial mucosal biopsies and immunohistochemical analysis of patients who had been treated with or without BDP-inhalation. Our study enrolled 6 chronic severe asthmatics who were treated with 1,800 micrograms/day or more of BDP with regular use for more than 3 years (HD-BDP group), 6 mild asthmatics who were not treated with BDP (non-BDP group), and 6 control subjects. Specimens of bronchial mucosa were stained with anti-EG 2 (eosinophils), anti-UCHLA-1 (T lymphocytes) and anti-tryptase (mast cells). Although limited eosinophil infiltration was observed in the HD-BDP and control groups, a significant increase was noted in the non-BDP group. The infiltration of both T lymphocytes and mast cells exhibited a statistically significant increase in the non-BDP group compared to the HD-BDP and control groups. In chronic severe asthmatics, airway mucosal cell infiltration was reduced by high-dose and long-term inhaled BDP therapy, and BDP also relieved their asthmatic symptoms. However, in mild asthmatics, bronchial mucosal cell infiltration remained high. For such patients, we concluded that initiating BDP therapy from an early stage may bring clinical improvement and help prevent cell infiltration.

Exon and intron variants in the human tryptophan 2,3-dioxygenase gene: potential association with Tourette syndrome, substance abuse and other disorders

Defects in serotonin metabolism, and abnormalities in both blood serotonin and tryptophan levels, have been reported in many psychiatric disorders. Tryptophan 2,3-dioxygenase (TDO2) is the rate limiting enzyme for the breakdown of tryptophan to N-formyl kenurenine. Functional variants of this gene could account for the observed simultaneous increases or decreases of both serotonin and tryptophan in various disorders. We have identified four different polymorphisms of the human TDO2 gene. Association studies show a significant association of one or more of these polymorphisms and Tourette syndrome (TS), attention deficit hyperactivity disorder (ADHD) and drug dependence. The intron 6G-->T variant was significantly associated with platelet serotonin levels. Only the association with TS was significant with a Bonferroni correction (p = 0.005). Our purpose here is not to claim these associations are proven, but rather to report preliminary results and show that easily testable polymorphisms are available. We hope to encourage additional research into the potential role the TDO2 gene in these and other psychiatric disorders.

Effects of androgen withdrawal on the stem cell composition of the Shionogi carcinoma

The parent Shionogi mouse mammary carcinoma is androgen dependent but cells that survive hormone withdrawal progress and give rise to an androgen-independent tumor. To determine whether renewed growth might be attributed to the persistence or partial recovery of an androgenic stimulus, we compared the amount of dihydrotestosterone and nuclear androgen receptor in parent and recurrent tumors. The whole tissue concentration of dihydrotestosterone in the parent tumor before castration was 1.40 +/- 0.46 (SE) as compared with 0.22 +/- 0.10 pmol/mg of DNA in the recurrent tumor. The initial concentration of nuclear androgen receptor in the parent was 0.65 +/- 0.12 pmol/mg of DNA; this was reduced to zero within 24 h after castration. Also in keeping with the androgen independence, no receptor was detected in the nuclear fraction of the recurrent carcinoma. In an attempt to relate malignant potential to nonhormonal factors associated with progression, we compared the proportions of androgen-dependent and -independent tumorigenic (stem) cells in parent and recurrent tumors using an in vivo limiting dilution assay. The difference observed, i.e., one stem cell per 4000 tumor cells in the parent versus one stem cell per 200 tumor cells in the recurrent carcinoma, was consistent with a marked enrichment of stem cells in the latter. The proportion of androgen-independent stem cells was also determined by assaying tumor takes in female hosts. The difference, i.e., one stem cell per 370,000 tumor cells in the parent versus one stem cell per 800 tumor cells in the recurrent carcinoma, demonstrated a striking 500-fold increase in androgen-independent stem cells resulting from androgen withdrawal. Unexpectedly, no enrichment of androgen-independent stem cells was evident in regressing parent tumors; rather, the proportion of such cells was very small, i.e., one androgen-independent stem cell per 2,200,000 regressing parent cells. This finding implies that the androgen-independent state of cells which survive androgen withdrawal may result from the ability of a small number of initially androgen-dependent stem cells to adapt to an altered hormone environment.

Subinhibitory antibiotics reduce Pseudomonas aeruginosa tissue injury in the rat lung model

Using the agar-bead rat lung model, we evaluated the effects of subinhibitory antibiotic treatment upon Pseudomonas aeruginosa exoenzyme expression and lung injury in vivo. One hundred and twenty-eight animals were separated into two groups of 64 animals. One group was inoculated with P. aeruginosa DG1, and the other with P. aeruginosa 3740. Each of these two groups was divided into four subgroups of 16 animals on the basis of ten-day antibiotic treatment with ciprofloxacin, tobramycin and ceftazidime or untreated controls. P. aeruginosa DG1 is non-mucoid and expresses significant yields of exoenzyme S and elastase. P. aeruginosa 3740 is a mucoid organism isolated from the sputum of a cystic fibrosis patient, and demonstrates modest elastase activity only (10% of DG1 levels). Lung bacterial counts were similar in treatment and control groups. Lungs from antibiotic-treated rats demonstrated fewer histological changes than those from untreated animals (P less than 0.001). DG1 lung isolates from antibiotic-treated animals yielded less elastase and exoenzyme S compared with isolates from untreated animals (P less than 0.001). No detectable decrease in elastase or mucoid phenotype was observed in 3740 lung isolates from antibiotic treated animals. Thus, antibiotic protection against lung injury by P. aeruginosa may involve modulation of virulence factors.

Inhibition of Pseudomonas aeruginosa exoenzyme expression by subinhibitory antibiotic concentrations

We examined the effects of subinhibitory concentrations of ciprofloxacin, tobramycin, and ceftazidime on Pseudomonas aeruginosa exoenzyme expression in vitro and in vivo. Exotoxin A, exoenzyme S, phospholipase C, elastase, and total protease activities were suppressed by antibiotics at concentrations as low as 1/20 of the MIC over a 24-h period in broth. Continuous 10-day exposure of P. aeruginosa DG1 broth cultures to antibiotic levels equal to 1/10 of the MIC reduced exoenzyme S activity in all treatment groups. Elastase activity was reduced only by ciprofloxacin and tobramycin treatment. This suppressive effect of the antibiotics persisted throughout the 10 days and was not influenced by the increase in MIC of ciprofloxacin detected during the course of the experiment. Rats chronically infected with P. aeruginosa were treated with subinhibitory doses of antibiotics and compared with untreated controls. Bacterial numbers in lung homogenates from each of the four study groups were identical. However, the lungs from antibiotic-treated rats had significantly less histological damage than those from control rats (P less than 0.001). The protective effect was greatest for ciprofloxacin and tobramycin. Further, P. aeruginosa isolates from ciprofloxacin- and tobramycin-treated rats demonstrated significantly less exoenzyme S and elastase activity than isolates from untreated rats (P less than 0.001). Isolates from ceftazidime-treated lungs expressed less exoenzyme S activity (P less than 0.001) but an equivalent amount of elastase activity as isolates from controls. The suppression of P. aeruginosa exoenzymes may arrest progressive lung injury during chronic P. aeruginosa lung infections.

Immunological cross-reactivity of a Mycoplasma pneumoniae membrane-associated protein antigen with Mycoplasma genitalium and Acholeplasma laidlawii

A murine monoclonal antibody, OC2F5, reacts with a Mycoplasma pneumoniae antigen with an approximate Mr of 43,000. This antigen is trypsin and proteinase K sensitive and partitions in the detergent phase of a Triton X-114 solution. The monoclonal antibody cross-reacts with an antigen from both Mycoplasma genitalium and Acholeplasma laidlawii with a similar molecular weight. This cross-reactivity should be considered in the development of M. pneumoniae antigen detection systems based on the use of antibodies directed to this protein antigen.

Mechanism of adhesion of Alysiella bovis to glass surfaces

Alysiella bovis adheres to surfaces by means of short, ruthenium red-staining, rod-like fimbriae. The fimbriae remain associated with the cell envelope of A. bovis, even when sonicated or exposed sequentially to toluene, Triton X-100, lysozyme, ribonuclease, and deoxyribonuclease. Adhesion of outer membrane-derived cell wall ghosts of A. bovis to glass was inhibited by IO4-, sodium dodecyl sulfate, urea, pronase, and trypsin. Protease treatment digested the fimbriae from the distal end, and exposure to sodium dodecyl sulfate depolymerized the fimbriae. Exposure of ghosts to 1% sodium dodecyl sulfate preferentially solubilized a 16,500-dalton protein which was subsequently purified by gel filtration and demonstrated to be a glycoprotein (ca. 17% carbohydrate). Antibodies raised against the 16,500-dalton glycoprotein agglutinated whole cells and inhibited adhesion of ghosts to glass.

Active immunization against tetanus III. Results of a five year study

This is the first time in Burma that tetanus toxoids (purified and adsorbed) have been tested in over 250 non-immune adult volunteers and studied for a period of nearly five years. The safety and efficacy of these toxoids have been assessed by immunological, statistical and clinical methods. Both toxoids were found to be safe. The adsorbed toxoid was far superior to the fluid toxoid as an immunizing agent and optimum immunization regimens are proposed and presented.

Pre-exposure prophylaxis of humans against rabies: I. Studies on personnel at the Burma Pharmaceutical Industry

This is the first time in Burma where personnel at risk against rabies have been pre-immunized and the effectiveness of such a procedure has been studied for nearly two years. The first batch of lyophilized, Semple-type, beta propiolactone inactivated anti rabies vaccine produced by the Burma Pharmaceutical Industry (B.P.I.) was used to immunize 55 B.P.I. workers previously unexposed to rabies and with no history of rabies vaccination. Three doses of 0.25 ml of the vaccine were given intradermally at one week intervals. Booster doses were given on the 98th, 392nd and 592nd day after the first dose. Blood samples were taken and serum neutralization tests were performed at varying time intervals after basic immunization and booster doses. Satisfactory antibody responses were obtained. The course of immunological response is presented and discussed.