The paediatric thymus: recognising normal and ectopic thymic tissue

The appearance of the paediatric thymus changes as the normal process of thymic involution occurs. Thymic tissue may be orthotopic within the anterior mediastinum or ectopically located along the course of its embryological development. The variable appearance of orthotopic and ectopic thymic tissue in children on imaging studies may lead to misinterpretation of the normal thymus as pathology. Recognition of normal thymic tissue can mitigate unnecessary further diagnostic testing and patient anxiety. In this review, we discuss the embryological development and anatomical variants of normal thymus, and demonstrate the multimodality imaging features of the normal thymus in children, including positron-emission tomography, and diffusion-weighted imaging and in- and opposed-phase imaging on magnetic resonance imaging. We demonstrate the normal thymus mimicking pathological processes and discuss features that distinguish normal thymus, including thymic rebound hyperplasia, from pathology.

Iatrogenic endometriosis harbors somatic cancer-driver mutations

STUDY QUESTION

Does incisional endometriosis (IE) harbor somatic cancer-driver mutations?

SUMMARY ANSWER

We found that approximately one-quarter of IE cases harbor somatic-cancer mutations, which commonly affect components of the MAPK/RAS or PI3K-Akt-mTor signaling pathways.

WHAT IS KNOWN ALREADY

Despite the classification of endometriosis as a benign gynecological disease, it shares key features with cancers such as resistance to apoptosis and stimulation of angiogenesis and is well-established as the precursor of clear cell and endometrioid ovarian carcinomas. Our group has recently shown that deep infiltrating endometriosis (DE), a form of endometriosis that rarely undergoes malignant transformation, harbors recurrent somatic mutations.

STUDY DESIGN, SIZE, DURATION

In a retrospective study comparing iatrogenically induced and endogenously occurring forms of endometriosis unlikely to progress to cancer, we examined endometriosis specimens from 40 women with IE and 36 women with DE. Specimens were collected between 2004 and 2017 from five hospital sites in either Canada, Germany or the Netherlands. IE and DE cohorts were age-matched and all women presented with histologically typical endometriosis without known history of malignancy.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Archival tissue specimens containing endometriotic lesions were macrodissected and/or laser-capture microdissected to enrich endometriotic stroma and epithelium and a hypersensitive cancer hotspot sequencing panel was used to assess for presence of somatic mutations. Mutations were subsequently validated using droplet digital PCR. PTEN and ARID1A immunohistochemistry (IHC) were performed as surrogates for somatic events resulting in functional loss of respective proteins.

MAIN RESULTS AND THE ROLE OF CHANCE

Overall, we detected somatic cancer-driver events in 11 of 40 (27.5%) IE cases and 13 of 36 (36.1%) DE cases, including hotspot mutations in KRAS, ERBB2, PIK3CA and CTNNB1. Heterogeneous PTEN loss occurred at similar rates in IE and DE (7/40 vs 5/36, respectively), whereas ARID1A loss only occurred in a single case of DE. While rates of detectable somatic cancer-driver events between IE and DE are not statistically significant (P > 0.05), KRAS activating mutations were more prevalent in DE.

LIMITATIONS, REASONS FOR CAUTION

Detection of somatic cancer-driver events were limited to hotspots analyzed in our panel-based sequencing assay and loss of protein expression by IHC from archival tissue. Whole genome or exome sequencing, or epigenetic analysis may uncover additional somatic alterations. Moreover, because of the descriptive nature of this study, the functional roles of identified mutations within the context of endometriosis remain unclear and causality cannot be established.

WIDER IMPLICATIONS OF THE FINDINGS

The alterations we report may be important in driving the growth and survival of endometriosis in ectopic regions of the body. Given the frequency of mutation in surgically displaced endometrium (IE), examination of similar somatic events in eutopic endometrium, as well as clinically annotated cases of other forms of endometriosis, in particular endometriomas that are most commonly linked to malignancy, is warranted.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by a Canadian Cancer Society Impact Grant [701603, PI Huntsman], Canadian Institutes of Health Research Transitional Open Operating Grant [MOP-142273, PI Yong], the Canadian Institutes of Health Research Foundation Grant [FDN-154290, PI Huntsman], the Canadian Institutes of Health Research Project Grant [PJT-156084, PIs Yong and Anglesio], and the Janet D. Cottrelle Foundation through the BC Cancer Foundation [PI Huntsman]. D.G. Huntsman is a co-founder and shareholder of Contextual Genomics Inc., a for profit company that provides clinical reporting to assist in cancer patient treatment. R. Aguirre-Hernandez, J. Khattra and L.M. Prentice have a patent MOLECULAR QUALITY ASSURANCE METHODS FOR USE IN SEQUENCING pending and are current (or former) employees of Contextual Genomics Inc. The remaining authors have no competing interests to declare.

TRIAL REGISTRATION NUMBER

Not applicable.

ZrO2-SBA-15 catalysts for the one-pot cascade synthesis of GVL from furfural

Controlling the zirconia coating thickness in ZrO₂-SBA-15 materials allows tuning their catalytic performance in the one-pot transformation of furfural into GVL.

Treatment persistence: a comparison among patients with schizophrenia who were initiated on atypical antipsychotic agents

BACKGROUND

Although clinical trials have demonstrated the efficacy of atypical antipsychotic agents in reducing symptoms of schizophrenia, the likelihood of sustaining control of schizophrenic symptoms may depend on treatment persistence.

OBJECTIVE

In this study, we compared treatment persistence between patients who were initiated on risperidone or olanzapine, the two most widely prescribed atypical antipsychotic agents.

METHOD

We identified patients with schizophrenia by ICD-9-CM codes (> or =1 inpatient or > or =2 outpatient ICD-9-CM codes > or =7 days apart) between 1 July 1998 and 30 June 1999. We further selected those who were prescribed the target drug during 1 April 1999 through 31 March 2000 provided that they were not on any antipsychotic agents during the prior 6 months. Using event history analysis, we compared the treatment persistence in terms of hazard ratio between olanzapine and risperidone initiators, adjusting for patient's sociodemographic and clinical characteristics.

RESULTS

Following the initiation of the target drug, more patients switched from risperidone to olanzapine than vice versa. However, among patients with schizophrenia who had comorbid diabetes, there were more patients who made a switch from olanzapine to risperidone; whereas among those who used anxiolytics, there were more patients who switched from risperidone to olanzapine. Finally, olanzapine initiators had decreased hazards of discontinuation by 14% (unadjusted; P < 0.001) and 12% (adjusted; P = 0.002), respectively, than risperidone initiators.

CONCLUSIONS

Compared with risperidone, olanzapine seems to be better tolerated by patients as indicated by better treatment persistence. As such, initiation of olanzapine may increase the likelihood of sustaining control of symptoms of schizophrenia. Future research needs to provide a more comprehensive assessment of treatment persistence by considering other antipsychotic agents in the study and developing models to assess treatment persistence and switching as two interdependent competing risks.

Adjunctive use of atypical antipsychotics and anticholinergic drugs among patients with schizophrenia

BACKGROUND

Treatment of schizophrenia with antipsychotics is often associated with extrapyramidal symptoms (EPS), a disorder involving involuntary muscle movement. Because EPS are often associated with the use of antipsychotics, anticholinergic agents are often indicated.

OBJECTIVE

In this observational, retrospective study, we examined whether the initiation of olanzapine or risperidone, the two most widely prescribed atypical antipsychotics, is related to the adjunctive use of anticholinergic agents.

METHOD

We identified patients with schizophrenia from outpatient clinics in the Veterans Health Administration (VA) and defined initiation of olanzapine or risperidone as patients who were not on any antipsychotics for 6 months and subsequently initiated on the target drug between 1/4/1999 and 31/3/2000. The data were analysed using tests of means or chi-square tests.

RESULTS

The study yielded two major findings. First, compared with risperidone initiators, there were significantly fewer olanzapine initiators who used at least one anticholinergic agent adjunctively. Secondly, among olanzapine or risperidone initiators, patients who used at least one anticholinergic agent adjunctively tended to stay on the target drug significantly longer than those who did not use any anticholinergic agent adjunctively with the target drug.

CONCLUSION

As the use of anticholinergics is a proxy for the presence of EPS, these findings suggest that risperidone may be more associated with EPS than olanzapine. However, to assess the benefits and side effects associated with olanzapine or risperidone, future research needs to examine various patient outcomes resulting from the initiation of each drug.

Initiation of atypical antipsychotic agents and health outcomes in patients with schizophrenia

BACKGROUND

Although pharmacological treatments are available for patients with schizophrenia, there is a lack of systematic and comprehensive evaluation of health outcomes following the initiation of atypical antipsychotic agents.

OBJECTIVE

To assess the effects of the initiation of olanzapine or risperidone, the two most widely prescribed atypical antipsychotics, on patients' health outcomes, as measured by changes in patient clinical characteristics between 6 months prior to and post-initiation.

METHOD

We identified patients with schizophrenia by >1 inpatient or > or = 2 outpatient ICD-9-CM codes (> or = 7 days apart) between 1 July 1998 and 30 June 1999, and those who were initiated on olanzepine or risperidone during the period 1 April 1999 to 31 March 2000 inclusive. We then subdivided these patients into three groups: (i) those who were not on olanzapine or risperidone, (ii) those who were not on any atypical agents, and (iii) those who were not on any antipsychotic agents, for 6 months prior to being issued with the new prescription. Using test of means or chi-square tests, we examined whether the initiation of olanzapine or risperidone is related to different changes in patient clinical indicators, such as number of drugs for psychiatric conditions, use of psychiatric services, and use of non-psychiatric services.

RESULTS

Between pre- and post-initiation, olanzapine initiators had a greater decrease in the number of psychiatric hospitalizations and use of psychotropic agents, whereas risperidone initiators had a greater reduction in the number of non-psychiatric hospitalizations. The initiation of olanzapine and risperidone appear to be associated with different patient health outcomes. Compared with olanzapine initiators, risperidone initiators had a greater increase in the use of treatments related to mental health, but had greater decrease in the use of treatments related to physical health.

CONCLUSION

Despite olanzapine and risperidone being often perceived as similar antipsychotic agents, our results suggest that the clinical outcomes associated with their use are different. Outcome data from routine clinical practice are required to provide a more comprehensive assessment of these drugs.

Patient characteristics and prescription patterns of atypical antipsychotics among patients with schizophrenia

BACKGROUND

Schizophrenia, one of the leading causes of disability, contributes substantially to the use of medical and mental health services. The treatment of schizophrenia is therefore particularly important to reduce deficits across a large number of neurocognitive domains.

OBJECTIVE

To describe the prescription (e.g. initiation and switching) patterns of atypical antipsychotic agents and examine the extent to which patient sociodemographic and clinical characteristics are associated with the prescription patterns of atypical antipsychotics among patients with schizophrenia.

METHODS

Using unique data sources from the Veterans Health Administration (VA), the study identified 89 107 patients with schizophrenia based on at least one inpatient or more than or equal to two outpatients' ICD-9-CM codes (> or =7 days apart). We defined a prior 6-month (1/1/99 to 6/30/99) and a post 6-month (7/1/99 to 12/31/99) period to describe patterns of initiation and switching of atypical antipsychotics.

RESULTS

Only a small number of patients were on clozapine (1.8%) and quetiapine (1.4%). More patients were prescribed olanzapine (23%) than risperidone (20%) (P < 0.001). Compared with patients who were on risperidone, those who were on olanzapine were younger (P < 0.001), more likely Hispanic (P < 0.001), more likely married (P < 0.05), had more service-connected disability (P < 0.001), had fewer numbers of physical comorbidities (P < 0.001), and a lower body mass index (BMI) (P < 0.05).

CONCLUSION

Olanzapine and risperidone appear to be prescribed to patients with different sociodemographic and clinical characteristics. Future research needs to explore the reasons for those differences.

Pulsatile ocular blood flow in asymmetric exudative age related macular degeneration

BACKGROUND/AIMS

Decreased perfusion or increased vascular resistance of the choroidal vessels had been proposed as the vascular pathogenesis for age related macular degeneration (AMD). This study planned to answer the question whether pulsatile ocular blood flow (POBF) was different in patients with asymmetric exudative AMD between eyes with drusen, choroidal neovascularisation (CNV), or disciform scar.

METHODS

37 patients with asymmetric exudative AMD were enrolled in this observational case series study. POBF were measured in both eyes of each subject. Eyes with high myopia, anisometropia, recent laser treatment, and glaucoma were excluded.

RESULTS

After adjusting for ocular perfusion pressure, intraocular pressure, and pulse rate, multivariate regression analysis with generalised estimating equation showed POBF was significantly higher in eyes with CNV (1217 (SD 476) microl/min) than the contralateral eyes with drusen (1028 (385) microl/min) (p = 0.024). Eyes with disciform scar had lower POBF than the contralateral eyes with drusen (999 (262) microl/min and 1278 (341) microl/min, respectively, p<0.001). There was no significant correlation between the POBF and the lesion size of the CNV.

CONCLUSION

The POBF in eyes with drusen was lower than their fellow eyes with CNV, but higher than their fellow eyes with disciform scar. This finding suggests that haemodynamic differences between fellow eyes in individuals are relevant to the development of CNV and the formation of disciform scar. Further studies on the follow up patients might shed light on the pathogenesis of exudative AMD.

Optic neuritis in herpes zoster ophthalmicus

BACKGROUND

Optic neuritis in herpes zoster ophthalmicus (HZO) has been reported rarely. We report two cases of HZO optic neuritis with detailed magnetic resonance imaging study and treatment responses.

CASES

One patient presented with anterior optic nerve involvement, and the second presented with retrobulbar optic neuritis. Contrast enhanced T(1)-weighted images were obtained in these 2 patients. Intravenous acyclovir and oral prednisolone were given simultaneously.

OBSERVATIONS

Magnetic resonance imaging revealed peripheral enhancement of the optic nerve sheath complex on T(1)-weighted scan. Both patients recovered their vision within 3 months following the start of treatment.

CONCLUSIONS

Magnetic resonance imaging is helpful for the diagnosis of HZO optic neuritis. Systemic acyclovir and steroid are effective in the treatment of HZO optic neuritis.

Ovarian hormones in man: their effects on resting vascular tone, angiotensin converting enzyme activity and angiotensin II-induced vasoconstriction

AIMS

Oestrogens in women have been shown to cause vasodilation which may reflect alterations in the activity of vascular angiotensin converting enzyme (ACE) and/or sensitivity to angiotensin II. The aim of this study was to assess the effect of ovarian hormones on vascular tone, vascular ACE activity and vasoconstriction to angiotensin II in males.

METHODS

Eight volunteers were randomised in a crossover design to oestradiol, medroxy-progesterone, and placebo. Vasoconstriction to angiotensin I and angiotensin II was assessed by forearm plethysmography.

RESULTS

Although baseline forearm flow was increased with oestradiol, suggesting generalized vasodilation, there were no changes in the vasoconstrictor responses to angiotensin I or angiotensin II. Medroxy-progesterone affected neither baseline flow nor vasoconstrictor responses. The results expressed as percentage reduction in flow (mean +/- s.d.) were: angiotensin I 48 pmol ml-1: placebo -48 +/- 14%; oestradiol -42 +/- 16%; medroxyprogesterone -43 +/- 8% and for angiotensin II 16 pmol ml-1: placebo -42 +/- 10%; oestradiol -39 +/- 11%; medroxyprogesterone -46 +/- 13%.

CONCLUSIONS

Acute administration of oestradiol caused vasodilation in males, the effect was not due to alterations in vascular ACE activity or to altered sensitivity to angiotensin II.

Neurohormonal reactivation in heart failure patients on chronic ACE inhibitor therapy: a longitudinal study

BACKGROUND

Angiotensin Converting Enzyme inhibitors reduce mortality in heart failure. One therapeutic mechanism is believed to be the reduction of circulating angiotensin II and aldosterone. However, the Renin-Angiotensin-Aldosterone axis (RAAS) is not uniformly suppressed during therapy for heart failure. This effect has been referred to as 'angiotensin II reactivation' and 'aldosterone escape' and their reactivation may herald clinical deterioration. In the CONSENSUS I trial, correlations were seen between mortality, and angiotensin II and aldosterone. Furthermore, mortality was lower in those with good angiotensin II suppression. Therefore, neurohormonal elevation despite adequate treatment may associate with a poorer prognosis.

AIMS

To follow chronic heart failure patients on ACE inhibitors for 18 months to assess whether or not angiotensin II and aldosterone reactivation are progressive with time, whether reactivation of both occurs simultaneously, and whether different ACE inhibitors have different neurohormonal profiles.

METHODS AND RESULTS

We studied 22 patients (M/F 19:3, 72.5+/-7 years) on stable ACE inhibitors. Five times, in 18 months, samples were taken for neurohormones and ACE activity. Mean levels of neurohormones were remarkably stable over time, although captopril takers had generally higher angiotensin II, but lower aldosterone and renin. Aldosterone 'escape' (> 80 pg/ml) occurred in 13/97 samples (13.5%), in 5/22 (23%) individuals. Angiotensin II was elevated > or =10 pg/ml in 8/102 samples (8%), in 6/22 (27%) individuals. Four subjects had isolated angiotensin II reactivation, and three had aldosterone escape alone. On regression analyses between neurohormones in captopril takers there were significant correlations between; renin and angiotensin II (r = 0.62; P<0.02); angiotensin II and aldosterone (r = 0.6; P<0.02); and renin and aldosterone (r = 0.92; P<0.00001).

CONCLUSION

In stable heart failure patients un-suppressed levels of angiotensin II and aldosterone occur despite therapy, but they are not necessarily progressive, nor simultaneous. Furthermore, contemporaneous serum ACE activity makes it unlikely the data presented reflects poor compliance. The results suggest that captopril takers may have different neurohormonal profiles, i.e. higher angiotensin II, and also better correlations between RAAS components, compared to longer acting preparations, although the numbers are small. Our data supports that of Swedberg et al. who showed reductions in both aldosterone and angiotensin II due to ACE inhibitor therapy, but no correlation between ACE activity and angiotensin II and only a limited correlation (r = 0.37) between angiotensin II and aldosterone. This suggests that the interaction between the components of the renin-angiotensin system is not simple and linear. The fact that each phenomenon appears to occur in isolation means that neurohormonal monitoring of individual could provide useful information to direct additional therapy. The RALES study has demonstrated reduced mortality from the addition of spironolactone to an ACE inhibitor emphasising the benefit of enhanced suppression of aldosterone in heart failure. Captopril may be less effective at suppressing the RAAS due to its short duration of action which would logically be associated with a more fluctuating pattern of ACE inhibition. In the presence of high levels of renin and angiotensin I even small differences in ACE activity will produce large variations in angiotensin II levels. Further studies should be directed at understanding the different mechanisms behind angiotensin II and aldosterone generation during ACE inhibition.

Indocyanine green angiography of central serous chorioretinopathy

BACKGROUND

Fluorescein angiography has not been particularly useful in studying the choroidal vasculature because of limited fluorescence transmission through the retinal pigment epithelium (RPE). Indocyanine green (ICG), a dye that absorbs and fluoresces in the near-infrared range and does not leak extensively through the choriocapillaries, because of its highly protein-bound nature, allows improved imaging of the choroid compared with fluorescein angiography. This study was performed to evaluate changes in the choroidal circulation in the eyes of patients with central serous chorioretinopathy (CSCR) using ICG angiography.

METHODS

We prospectively performed ICG angiography and fluorescein angiography in 41 eyes with classic or chronic CSCR (diffuse retinal pigment epitheliopathy) to investigate the choroidal abnormalities.

RESULTS

The ICG angiographic studies revealed choroidal staining in all eyes of the two forms of CSCR. Classic CSCR (35 eyes), when compared with the chronic form (6 eyes), were associated with more RPE leakage (89% vs 33%; p = 0.008), more prominent ischemic lobules (69% vs 0; p = 0.003), and less late phase hypofluorescent spots (46% vs 100%; p = 0.02).

CONCLUSIONS

Choroidal hyperpermeability may be a causative factor of acute or chronic CSCR and may help in the diagnosis of atypical cases of CSCR. The differences in the results between these two types of CSCR using ICG angiography, allowed for a better understanding of the choroidal hemodynamic change than fluorescein angiography.

The effect of nitric oxide inhibition on the renin response to frusemide, in man

AIMS

We wished to see if renin release in man was inhibited by nitric oxide blockade, suggesting a role for nitric oxide in renin release. Evidence from animal studies has shown variable effects on renin release depending on the model and stimulus used.

METHODS

Ten normal male volunteers, received either L-NMMA as a front loaded infusion (4 mg kg-1 bolus, with 4 mg kg-1 infusion), or placebo, followed by an intravenous bolus of 5 mg frusemide to stimulate renin. To investigate whether any alteration in renin release was due to the pressor effect of the L-NMMA, the experiment was repeated using an equipressor dose of phenylephrine (0.5 microg kg-1 min-1 ).

RESULTS

L-NMMA caused the expected increase in mean arterial pressure (96+/-2.6 vs 89+/-3.3 mmHg P<0.05 [mean+/-s.e.mean]), and a reduction in heart rate (59+/-3.6 vs 67+/-2.5 beats min-1 P<0.05). L-NMMA completely blocked the renin rise following the bolus of frusemide (1.18+/-0.196 vs 1.96+/-0.333 ng ml-1 h-1 P<0.01). Phenylephrine 0.5 microg kg-1 min-1 produced very similar haemodynamic effects to L-NMMA, and also suppressed the renin response to frusemide (1.43+/-0.290 vs 2.67+/-0.342 ng ml-1 h-1 P<0. 01).

CONCLUSIONS

In man, the renin inhibition seen with NO synthesis inhibition is similar to that seen with a standard pressor stimulus, hence inhibition of renin in man by L-NMMA, may be due to both direct effects on macula densa cells and indirect haemodynamic effects.

How often are angiotensin II and aldosterone concentrations raised during chronic ACE inhibitor treatment in cardiac failure?

OBJECTIVE

Angiotensin II (AII) and aldosterone are not always fully suppressed during chronic angiotensin converting enzyme (ACE) inhibitor treatment. In congestive heart failure (CHF) such failure of hormonal suppression is associated with increased mortality. This study examined how common AII and aldosterone increases are observed during routine clinical practice.

PATIENTS AND METHODS

91 patients with symptomatic (mean New York Heart Association class 2.7) CHF (mean (SD) left ventricular ejection fraction 29.9 (8)%, range 9-46%) were studied 4-6 hours after ACE inhibitor dosing. A representative range of ACE inhibitors (enalapril, lisinopril, captopril, perindopril, and fosinopril) was examined.

RESULTS

Supine measurements showed a wide range of AII (10.5 (25.5) pg/ml), aldosterone (130.8 (136) pg/ml), and serum ACE (12.1 (13.3) EU/l; excludes captopril data) concentrations on diuretics. AII concentrations > 10 pg/ml were seen in 15% of patients, and aldosterone concentrations > 144 pg/ml were seen in 38% of patients. AII concentrations were significantly correlated (p < 0.001) with ACE but not with aldosterone concentrations. Aldosterone concentrations were not significantly correlated with ACE concentrations.

CONCLUSIONS

AII "reactivation" occurred in 15% and failure of aldosterone suppression in 38% of routine CHF patients taking ACE inhibitor treatment. AII "reactivation" was associated with both low and high levels of ACE activity, which suggests that multiple different mechanisms are at play. In patients with high plasma ACE concentrations, non-compliance should be considered along with inadequate dose titration. In patients with low plasma ACE and high AII concentrations, non-ACE mediated production of AII may be operative. Raised aldosterone concentrations appear to be more common than AII "reactivation". It is important to establish the cause of detectable or increased AII concentrations in a heart failure patient treated with an ACE inhibitor. The measurement of serum ACE may help to identify the likely cause as poor compliance or inadequate dose.

Lisinopril improves arterial function in hyperlipidaemia

Endothelial function is defective in hypercholesterolaemia, and animal models have suggested that angiotensin-converting enzyme inhibitors may prevent arterial damage. We studied the effect of 6 months treatment with lisinopril on endothelial function in a group of patients with hypercholesterolaemia. Forty patients were studied. Forearm blood flow responses to acetylcholine and sodium nitroprusside were assessed by venous occlusion plethysmography. Subjects were then randomized in a double-blind fashion to receive either lisinopril, 20 mg/day (n=20), or placebo (n=20) for 6 months. Plethysmography was then repeated. Baseline variables between groups were comparable. In the lisinopril group blood pressure fell significantly [systolic: 145+/-4 to 128+/-4 mmHg (P<0.001); diastolic: 84+/-2 to 74+/-2 mmHg (P<0.001)]. An improvement was found in the vasodilatory response (expressed as a ratio of the infused/control arm) to acetylcholine, e.g. 3.33+/-0.3 (pre) versus 4.45+/-0.48 (post) at 30 microg/ml (P<0.03), and also to nitroprusside, e.g. 3.0+/-0.2 (pre) versus 3.86+/-0.3 (post) at 3.2 microg/ml (P<0.01). In the placebo group vasodilatation did not change significantly in response to acetylcholine, and nitroprusside responses were unchanged. The data presented suggest that 6 months of lisinopril therapy have a beneficial effect on arterial function in subjects with hyperlipidaemia. Further work should now investigate whether angiotensin-converting enzyme inhibitors are beneficial in reducing mortality and morbidity in hypercholesterolaemia.

Decision-making preference and opportunity in VA ambulatory care patients: association with patient satisfaction

Using data from the Veterans Health Study, associations were examined for decision-making preference, decision-making opportunity, and satisfaction with medical care among a sample of 266 men who use Department of Veterans Affairs (VA) ambulatory health care services. Results indicated that veterans with a high preference for involvement in decision-making and low provider-offered decision-making opportunities had significantly lower satisfaction with medical care compared to veterans with either low preference for decision-making involvement with high or low opportunity, or those with a high decision-making preference and high decision-making opportunity. The findings suggest that health care providers may increase patient satisfaction with medical care by providing opportunities for decision-making to patients who prefer involvement in their health care decision-making. Provider strategies for increasing patient decision-making involvement are discussed.

Nitric oxide: an important role in the maintenance of systemic and pulmonary vascular tone in man

AIMS

The aim of this study was to examine whether nitric oxide (NO) has an important role in maintaining basal vascular tone in normal man by examining the effects of nitric oxide inhibition using N(G)-monomethyl-L-arginine (L-NMMA) on systemic and pulmonary haemodynamics.

METHODS

Ten normal male volunteers 26 +/- 1.6 years were studied on two separate occasions in a double-blind, placebo controlled crossover study. They were randomised to receive either a continuous infusion of L-NMMA (4 mg kg(-1) h(-1)) with a front loaded bolus (4 mg kg(-1)) or volume matched placebo. Pulsed wave Doppler echocardiography was used to measure cardiac output (CO), mean pulmonary artery pressure (MPAP) and hence systemic vascular resistance (SVR) and total pulmonary vascular resistance (TPR). Measurements were made prior to infusion (t0) and after 4, 8, and 12 min (t1, t2 and t3).

RESULTS

Infusion of L-NMMA significantly increased mean arterial blood pressure (MAP), SVR and TPR and significantly reduced heart rate (HR), stroke volume (SV) and CO compared to placebo. These effects were observed at t1 and persisted during the entire infusion period.

CONCLUSIONS

These results are consistent with a role for basal nitric oxide generation in the maintenance of basal systemic and pulmonary vascular tone in normal man.

Choroidal involvement in Wegener's granulomatosis: a case report

Wegener's granulomatosis is a necrotizing, granulomatous vasculitis. It usually causes sinusitis, pneumonitis and glomerulonephritis. The common ocular manifestations include conjunctivitis, scleritis, peripheral keratitis and orbital inflammation. We report the case of a 50-year-old woman with Wegener's granulomatosis and very severe ocular complications who underwent bilateral enucleation. The pathologic findings of the eyeballs revealed granulomatous necrotizing scleritis, perivasculitis and granulomatous choroiditis. The last, as far as we know, has not yet been reported.

The impact of angiotensin converting enzyme inhibitors on the arterial wall

There is recent interest in the possibility that angiotensin converting enzyme inhibitors (ACE inhibitors) may reduce the damage inflicted on the arterial wall by common cardiovascular risk factors such as hypertension, hyperlipidaemia and ageing. The efficacy of these drugs in blood pressure reduction is accepted, but whether there is an excess benefit on arterial structure and function, conferred by use of ACE inhibitors over more traditional antihypertensives, is still under debate. There is also evidence in animal models to suggest that ACE inhibition is effective in reduction of arterial damage due to experimental hyperlipidaemia. ACE inhibitors not only reduce the conversion of angiotensin I and angiotensin II, which can interact with the sympathetic nervous system, but also prevent the degradation of bradykinin. This means that ACE inhibitors have several potential mechanisms through which they could suppress intimal hypertrophy and prevent endothelial dysfunction, which is believed to precede arteriosclerosis in man. Although much further work is needed to clarify the mechanism underlying the beneficial effects on the arterial wall of this group of drugs, they do appear to have significant potential in the effort to reduce cardiovascular mortality and morbidity, especially in high risk groups.

Glaucoma following congenital cataract surgery

BACKGROUND

Glaucoma is a well known complication that arises after congenital cataract surgery. The purpose of this research was to study eyes that manifested glaucoma after congenital cataract surgery and to identify associated factors.

METHODS

A retrospective review of patients who received cataract surgery before the age of five was conducted. The chi-squared test for association was used to evaluate risk factors.

RESULTS

One hundred and forty eyes of 85 patients were studied. Nineteen eyes of 12 patients had glaucoma, among which 79% was open angle. Patients who underwent secondary membranectomy for visual axis occlusion had a higher risk of glaucoma, especially when secondary membranectomy was performed within one year of primary surgery. Of eight eyes with microcornea, none developed glaucoma after surgery. No significant difference in outcome was found among the surgical methods of cataract removal.

CONCLUSIONS

Aggressive clearance of lens cortex during surgery is important. Secondary membranectomy for clearing the visual axis occlusion is associated with post operative glaucoma. Frequent and long-term patient follow-up is mandatory since glaucoma may manifest many years after congenital cataract surgery.

Recidivism rates among child molesters and rapists: a methodological analysis

We address the high variability in sex offender recidivism rates by examining several of the critical methodological differences that underlie this variability. We used a dataset on 251 sex offenders (136 rapists and 115 child molesters) who were discharged over a 25-year period to examine changes in recidivism as a function of changes in dispositional definition of reoffense (e.g., arrest or conviction), changes in the domain of criminal offenses that are considered, and changes in the length of exposure time. The data indicate that: (a) both rapists and child molesters remain at risk to reoffend long after their discharge, in some cases 15-20 years after discharge; (b) there was a marked underestimation of recidivism when calculating a simple proportion (%) consisting of those who were known to have reoffended during the follow-up period, and (c) there was a marked underestimation of recidivism when the criterion was based on conviction or imprisonment. Forensic, clinical and policy implications of this high variability are discussed.

Risk factors associated with recidivism among extrafamilial child molesters

This study examined the predictive efficacy of 10 rationally derived, archivally coded variables for assessing reoffense risk among extrafamilial child molesters. Follow-up data on 111 child molesters who were discharged from the Massachusetts Treatment Center between 1960 and 1984 were used. Degree of sexual preoccupation with children, paraphilias, and number of prior sexual offenses predicted sexual recidivism. Juvenile and adult antisocial behavior, paraphilias, and low amount of contact with children predicted nonsexual victim-involved and violent recidivism. Area under the receiver-operating characteristic curves in all three analyses indicated discrimination that was substantially better than chance, ranging from .73 to .79.

N-CAM promotes recovery in injured nerves

The neural cell adhesion molecule, N-CAM, makes critical contributions to the development of the nervous system. It mediates the stability of homophilic adhesion in embryonic neurons and participates in morphologic differentiation. The goal of these studies was to determine N-CAM contributions to nerve regeneration and recovery of function in two species with an excised segment of sciatic nerve. N-CAM was isolated from embryonic brains, affinity purified and admixed in collagen gel for administration. Recovery was compared 30 days after surgery for two types of N-CAM delivery: entubulization versus direct application. For control nerves, tubes contained gel only. In preliminary chicken studies, latency of nerve responses was measured to demonstrate N-CAM's ability to improve upon spontaneous recovery. In subsequent studies of rodent nerves, the direct application of N-CAM significantly improved recovery in evoked nerve response amplitude, number of regenerated axons and behavioral activity. Results demonstrate N-CAM's ability to augment nerve regeneration and suggest a potential for therapeutic use.

Adrenal corticosteroid secretion in fetal sheep: pulsatile pattern at rest

This study was undertaken to define the resting pattern of fetal pituitary-adrenocortical function. Experiments were performed at 127-145 days gestation in fetal sheep with chronic peripheral and adrenal cannulas inserted under halothane anesthesia. With the fetus in a baseline state, over 6 h, at 30-min intervals, maternal and fetal peripheral samples were collected for blood gases and cortisol (F), corticosterone (B), and adrenocorticotropic hormone (ACTH) concentrations, and three successive, 2-min adrenal samples were collected for determination of F and B secretion rates. We observed high-frequency, episodic bursts of F secretion. A lower frequency oscillation of F secretion, with a period of approximately 90 min, was defined by cosinor analysis. The mean amplitude of the oscillation increased from 45 to 507 ng/min with advancing gestation. The pattern of B secretion was similar to that for F but was quantitatively lower. An oscillatory period of approximately 90 min for plasma F was present in a majority of experiments. Pulsatile rhythms for ACTH were defined in 10 of 14 experiments, with periods ranging from 1.64 h in the least mature group to 2.37 h in the oldest fetus. Mean data revealed exponential increases in both F secretion and plasma ACTH from 129 to 145 days gestation.

Intramuscular versus intravenous ritodrine hydrochloride for preterm labor management

A prospective, interinstitutional comparative trial was undertaken to examine the efficacy, safety, and pharmacodynamics of different administration routes of ritodrine hydrochloride for the management of preterm labor. Forty-five subjects between 20 and 36 weeks' gestation received either intravenous (n = 24) or intramuscular (n = 21) therapy. Successful tocolysis occurred in 14 of 21 (67%) patients in the group treated intramuscularly and in 16 of 24 (67%) patients in the group treated intravenously. A greater mean dose (8.6 versus 3.3 mg/hour) and a higher mean serum concentration (38.9 versus 24.7 micrograms/ml) were needed to achieve successful tocolysis in the intravenous group as compared with the intramuscular group. Patients who did not respond to tocolytic therapy in both groups had levels of ritodrine in the blood either equivalent to or greater than those of subjects who were successfully treated. Analysis of ritodrine levels in the successfully treated intramuscular group demonstrated significant differences in blood levels depending on muscle group used. These differences can be at least partially attributed to higher mean doses administered to patients receiving vastus lateralis injections as compared with those receiving gluteal muscle injections. The results suggest that intramuscular administration of ritodrine is an efficacious and safe route of drug delivery. Additional studies are needed to better define dose-response curves for the intramuscular administration of ritodrine hydrochloride.

The relationship between sleep and sudden infant death

Infants epidemiologically at high risk for SIDS demonstrate a variety of abnormalities in sleep-state organization, maturation, and sleep-state modulation of cardio-respiratory control mechanisms. These involve both the REM and quiet-sleep states and are seen in twins who have had no evidence of clinical cardio-respiratory compromise during infancy as well as in near-miss infants who have suffered serious cardio-respiratory failure. Although these infants have higher levels of REM sleep around 40 weeks, of special concern is the decrease in the maturation of the quiet system, which becomes evident after 44 weeks, and the reported quiet-sleep abnormalities in reflex control of respiration and arousal. The source of these abnormalities is environmental rather than genetic and most likely occurs prenatally. During the critical period for SIDS, infant sleep begins to coalesce from a series of naps to more prolonged night time sleep periods that last up to 8 hours. We believe that the ability to maintain physiologic homeostasis during prolonged sleep is a challenge facing infants who are epidemiologically at risk for sudden infant death. The challenge facing sleep research is the more complete understanding of the relationship between prolonged inhibition, homeostasis, arousal, and development.

Open dorsal dislocations of the proximal interphalangeal joint

Eighteen open dorsal dislocations of the proximal interphalangeal joint were treated in 17 patients over a 12-year period. The severity of this injury may be underestimated. Complications included synovitis, stiffness, septic arthritis, and loss of the digit. Factors associated with a poor prognosis included a concomitant injury to the hand, a fracture from the base of the middle phalanx, and treatment in the emergency room. For optimum results, we recommend antibiotic therapy, thorough debridement in the operating room, reattachment of the palmar plate and repair of the collateral ligaments if necessary, and temporary joint immobilization (3 weeks) followed by an aggressive range of motion program.

Confirmation of the assignment of human biliverdin reductase to chromosome 7

Segregation of biliverdin reductase (BLVR) in 11 independent human-mouse hybrids confirms the assignment to chromosome 7 in man and gives a regional localization of 7pter----7q22. Isoelectric focusing of BLVR reveals genetically determined variation among inbred strains of mice.

Evaluation of evoked-muscle potentials from stimulation of ulnar nerves of the dog

Evoked muscle potentials were evaluated in 19 anesthetized dogs after stimulation of the ulnar nerve. Subsequently, unilateral dorsal rhizotomy was performed on 6 dogs, and ulnar nerve stimulation was repeated. The evoked muscle potentials were begun at 1 V and increased. Threshold, optimum, and maximum stimuli for the M wave, and the reflex-evoked response (H reflex) were recorded. Threshold voltages for the M wave and the H reflex were 4.4 V and 4.0 V, respectively. The latencies for these stimuli also were recorded for the H reflex from proximal and distal sites. The optimal latency for the proximal and the distal sites were 15.4 +/- 2.5 ms and 18.3 +/- 2.6 ms, respectively (mean +/- SD). The motor nerve conduction velocity was 68 +/- 11 m/s. In addition, a mixed orthodromic sensory-antidromic motor conduction velocity was 75.2 +/- 13.3 m/s. Ratios between thoracic limb length and H reflex latency were 27.5 +/- 3.9 from the proximal site and 23 +/- 2.7 from the distal site. A waveform with a latency less than that of the H reflex, but greater than that of the M wave was observed inconsistently. An additional group of low amplitude waves was observed with a latency greater than the H reflex latency. The H reflex latency/limb length ratio may be clinically useful in evaluation of proximal neuropathies in the dog.

Factors affecting sleep spindle activity during infancy

Sleep spindle activity was evaluated in 32 twins at 52 weeks postconceptional age. Significantly increased mature spindle activity was seen in infants born at older gestational ages, in femals, and in infants who were stressed by intra-uterine growth retardation or with mild postnatal respiratory illness.

Apnea and sleep state in infants with nasopharyngitis

Having a mild upper respiratory tract infection does not change the sleep rate proportions or total sleep time of an infant. However, infants with colds exhibit some sleep state specific alterations in sleep apnea. At 40, 44, and 48 weeks postconception, the number of respiratory pauses of 2 to 4.9 seconds and of 5 to 9.9 seconds duration per 100 minutes of state, during rapid eye movement, and indeterminate sleep are decreased in infants with colds. The absence of this phenomenon at 52 weeks suggests that it is modified by maturation. We hypothesize that the reduction in rapid eye movement and indeterminate sleep apnea is a manifestation of an adaptive response in normal infants, but for infants at risk for the sudden infant death syndrome, this response may be overwhelmed, resulting in increased apnea and, in some instances, sudden infant death.

The sleep state characteristics of apnea during infancy

The sleep state characteristics of infant sleep apnea were studied in 36 twins examined by polygraphy at 40, 44, and 52 weeks after conception. The definition of sleep apnea is dependent upon the length of apnea, sleep state, and post-conceptional age. None of the infants had apnea longer than 20 seconds and apnea of 10 seconds or longer was uncommon. The attack rates for apneas 2 to 4.9 seconds long were highest in REM and lowest in qliet sleep. The attack rates for apneas 5 to 9.9 seconds long were equal in REM and indeterminate and lowest in quiet sleep. The percentage of infants with apnea of 10 seconds or longer at 40 weeks was highest in REM (27%) and indeterminate sleep (42%) and lowest in quiet sleep (12%). At 52 weeks, apnea 10 seconds or longer during REM decreased to 0%. The effect of maturation on apnea varies with sleep state. Over the period from 40 to 52 weeks, quiet sleep apnea was unchanged and indeterminate sleep apnea decreased only between 40 and 44 weeks. Although REM apnea 2 to 4.9 seconds long was unchanged, REM apnea 5 to 9.9 seconds long decreased between 40 and 44 weeks, and REM apnea of 10 seconds or longer decreased from 27% at 40 weeks to 0% at 52 weeks. This suggests that semi-independent apnea turn-on and turn-off mechanism operate during REM sleep. A correlation between brief apneas and the longer apneas was seen only during REM sleep. For all sleep states, there was no correlation between the levels of apnea of 5 seconds or longer at 40, 44, and 52 weeks.

Effect of tissue temperature on ulnar nerve conduction velocity in the dog

The motor conduction velocity of the ulnar nerve of 19 mature dogs anesthetized with pentobarbital was electromyographically determined before and at tissue temperature decrements of 2 degrees (C) during cooling of the forelimb. Precooling (37 C) conduction velocity was 56 +/- 7.6 m/second (mean +/- standard deviation). At a tissue temperature of 20 C, conduction velocity was reduced to 31 +/- 6.3 m/second. Regression analysis indicated that conduction velocity decreased linearly by 1.7 m/second for each degree of decrease in tissue temperature between 37 and 20 C.