The Atacama Rover Astrobiology Drilling Studies (ARADS) Project

With advances in commercial space launch capabilities and reduced costs to orbit, humans may arrive on Mars within a decade. Both to preserve any signs of past (and extant) martian life and to protect the health of human crews (and Earth's biosphere), it will be necessary to assess the risk of cross-contamination on the surface, in blown dust, and into the near-subsurface (where exploration and resource-harvesting can be reasonably anticipated). Thus, evaluating for the presence of life and biosignatures may become a critical-path Mars exploration precursor in the not-so-far future, circa 2030. This Special Collection of papers from the Atacama Rover Astrobiology Drilling Studies (ARADS) project describes many of the scientific, technological, and operational issues associated with searching for and identifying biosignatures in an extreme hyperarid region in Chile's Atacama Desert, a well-studied terrestrial Mars analog environment. This paper provides an overview of the ARADS project and discusses in context the five other papers in the ARADS Special Collection, as well as prior ARADS project results.

The Industrial Resurgence of Southern California? Advanced Ground Transportation Equipment Manufacturing and Local Economic Development

Southern California is in a deeply rooted process of economic restructuring. Much of the region's manufacturing base is made up of two groups of industries: A declining aerospace–defense sector, and a low-wage, low-skill sweatshop sector. What are the prospects for creating a growing manufacturing base focused on high-wage, high-skill industries? In this paper we examine the opportunities presented by the Los Angeles County Metropolitan Transportation Authority's $183 billion thirty-year capital improvement plan as the potential catalyst of a set of technological and manufacturing synergies that would reorient the regional economy towards a new advanced ground transportation equipment industry. We investigate the dynamics of agglomerated complexes of industry in general, and the institutional and infrastructural arrangements that create and sustain competitive advantage within regional economic systems. Next, we evaluate the potential for the successful development of a technologically dynamic advanced ground transportation equipment industry in Southern California. This central part of the analysis focuses on (a) the existing industrial assets of the region, (b) specific forms of institution building that need to be carried out in the interests of local economic development and high-quality job creation, and (c) the importance of building a cooperative, high-trust manufacturing system. We then offer suggestions for specific types of policy intervention that might foster new forms of local economic growth. We argue that a coordinated response by both the public and the private sectors could conceivably set the region on a successful new economic development trajectory.

Region-specific reductions in brain apparent diffusion coefficient in cytomegalovirus-infected fetuses

OBJECTIVE

To evaluate the effects of cytomegalovirus (CMV) infection on apparent diffusion coefficient (ADC) values of the fetal brain in utero.

METHODS

In this retrospective analysis we compared 58 fetal head magnetic resonance imaging (fhMRI) scans of PCR-verified CMV-infected fetuses, obtained in 2008-2012, with those of a normal control group of 36 gestational age (GA)-matched uninfected fetuses scanned between 2006 and 2012. Estimated GA at infection ranged from 1 to 32 weeks, and fhMRI was performed at 24 to 38 weeks. The frontal, parietal, temporal and occipital lobes (mainly white matter), basal ganglia, thalamus, pons and cerebellum were analyzed by assessing ADC values. Two pregnancies were terminated and postmortem confirmation was available in these cases.

RESULTS

ADC values of CMV-infected fetuses correlated significantly and negatively with GA in all brain regions except the basal ganglia. The cerebellum had the greatest reduction (r = -0.52, P < 0.0001). Maternal age correlated positively with ADC in the frontal lobe (P < 0.05). GA at infection and overt pathological changes did not affect ADC significantly. Compared with non-infected fetuses, ADC values of affected fetuses were significantly reduced in the frontal (P < 0.0001), parietal (P < 0.0001), occipital (P = 0.0005) and temporal (P = 0.001) lobes and thalamus (P = 0.006).

CONCLUSION

CMV infection of the fetal brain results in a highly significant, region-dependent reduction of ADC values in the frontal, parietal, occipital and temporal lobes and thalamus, probably reflecting hypercellularity and inclusion bodies in damaged areas. Further studies are needed to determine if reduction in ADC values may serve as a prognostic factor in CMV-infected fetuses. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.

MDD Propagation for Sequence Constraints

We study propagation for the Sequence constraint in the context of constraint programming based on limited-width MDDs. Our first contribution is proving that establishing MDD-consistency for Sequence is NP-hard. Yet, we also show that this task is fixed parameter tractable with respect to the length of the sub-sequences. In addition, we propose a partial filtering algorithm that relies on a specific decomposition of the constraint and a novel extension of MDD filtering to node domains. We experimentally evaluate the performance of our proposed filtering algorithm, and demonstrate that the strength of the MDD propagation increases as the maximum width is increased. In particular, MDD propagation can outperform conventional domain propagation for Sequence by reducing the search tree size and solving time by several orders of magnitude. Similar improvements are observed with respect to the current best MDD approach that applies the decomposition of Sequence into Among constraints.

Epigenetic regulation of the Igf2/H19 gene cluster

Igf2 (insulin-like growth factor 2) and H19 genes are imprinted in mammals; they are expressed unevenly from the two parental alleles. Igf2 is a growth factor expressed in most normal tissues, solely from the paternal allele. H19 gene is transcribed (but not translated to a protein) from the maternal allele. Igf2 protein is a growth factor particularly important during pregnancy, where it promotes both foetal and placental growth and also nutrient transfer from mother to offspring via the placenta. This article reviews epigenetic regulation of the Igf2/H19 gene-cluster that leads to parent-specific expression, with current models including parental allele-specific DNA methylation and chromatin modifications, DNA-binding of insulator proteins (CTCFs) and three-dimensional partitioning of DNA in the nucleus. It is emphasized that key genomic features are conserved among mammals and have been functionally tested in mouse. 'The enhancer competition model', 'the boundary model' and 'the chromatin-loop model' are three models based on differential methylation as the epigenetic mark responsible for the imprinted expression pattern. Pathways are discussed that can account for allelic methylation differences; there is a recent study that contradicts the previously accepted fact that biallelic expression is accompanied with loss of differential methylation pattern.

Bait acceptability for delivery of oral rabies vaccine to free-ranging dogs on the Navajo and Hopi Nations

In many areas of the world, only 30 to 50% of dogs are vaccinated against rabies. On some US Indian Reservations, vaccination rates may be as low as 5 to 20%. In 2003 and 2004, we evaluated the effectiveness of commercially available baits to deliver oral rabies vaccine to feral and free-ranging dogs on the Navajo and Hopi Nations. Dogs were offered one of the following baits containing a plastic packet filled with placebo vaccine: vegetable shortening-based Ontario slim baits (Artemis Technologies, Inc.), fish-meal-crumble coated sachets (Merial, Ltd.), dog food polymer baits (Bait-Tek, Inc.), or fish meal polymer baits (Bait-Tek, Inc.). One bait was offered to each animal and its behaviour toward the bait was recorded. Behaviours included: bait ignored, bait swallowed whole, bait chewed and discarded (sachet intact), bait chewed and discarded (sachet punctured), or bait chewed and consumed (sachet punctured). Bait acceptance ranged from 30.7% to 77.8% with the fish-meal-crumble coated sachets having the highest acceptance rate of the tested baits.

Stone bone syndrome--diffuse sclerosis of bone: a newly described clinical disorder

A 52-year-old man with severe bone pain was found to have diffuse sclerosis of bone and chronic hepatitis C infection. A bone biopsy specimen showed a normal lamellar appearance but dramatically increased bone-forming surfaces. A possible mechanism for this disorder is offered.

Burn injuries in children with attention-deficit/hyperactivity disorder

PURPOSE

Children with attention-deficit/hyperactivity disorder (ADHD) are at increased risk for traumatic injury than non-ADHD-children. Burn injuries in ADHD-children have not been studied. This study was conducted to determine differences in burn injuries between these groups.

METHODS

The charts of all children ages 5-18, admitted over a 7-year period to a single regional pediatric burn center, were reviewed. ADHD-children were compared to non-ADHD-children regarding age and gender, type and extent of burn, and burn injury outcome.

FINDINGS

There were 278 children included, 35 (13%) having ADHD. ADHD-children were more likely male but did not differ in age compared to non-ADHD-children. ADHD-children were more likely to experience a thermal rather than flame burn (83% versus 58% thermal, P < 0.01) and had more extensive burn injury (10% versus 5% median TBSA, P = 0.03). The ADHD group had a longer length of stay (11 versus 7 days, P = 0.05) and was less likely to be discharged to home (86% versus 93%, P = 0.17).

CONCLUSIONS

ADHD-children do differ from non-ADHD-children in their pattern and extent of burn injury. The impulsivity and vigilance deficits that characterize ADHD may place these children at higher risk for specific types of burn injuries.

A normal variant on Tl-201 and Tc-99m MIBI whole-body imaging: the superior right atrial wall (auricle) and superoanterior right ventricular wall are often seen as mediastinal lesions

PURPOSE

The authors have often observed on Tl-201 and Tc-99m sestamibi (MIBI) scans in patients with thyroid cancer a small focus of increased uptake in the right midparasternal region (focus A) or sometimes in the lower mid chest at the level of the lower sternum (focus B) just inferomedial to focus A. The objective of this study was to assess the frequency of this finding on Tl-201 MIBI studies, to assess the incidence of true pathologic lesions corresponding to these foci, and to identify their nature.

MATERIALS AND METHODS

One hundred ten whole body Tl-201 studies using 4 mCi (148 MBq) and 84 MIBI studies using 20 mCi (740 MBq: first-pass, planar, and SPECT images) were reviewed. The appearance of either focus A or focus B on three orthogonal SPECT images was correlated with an atlas of cross-sectional anatomy and computed tomography. If focus A was seen on the immediate static image (obtained at the end of the first-pass acquisition without moving the patient), this image was coregistered with a selected image from the first-pass study showing the superior vena cava and also with another selected image showing the ascending aorta.

RESULTS

Focus A was seen in 40% of Tl-201 scans and in 49% of MIBI scans, whereas focus B was seen in 20% of Tl-201 scans and 39% of MIBI scans. On correlation of the SPECT images with a cross-sectional anatomy atlas, focus A and focus B invariably corresponded to the superior portion of the right auricle and basal superoanterior right ventricular wall, respectively. These myocardial regions are prominent and sometimes appear as discrete foci because they are considerably thicker than other parts of the right atrial and right ventricular muscle, respectively, and because they are seen partly end-on in the anterior projection.

CONCLUSIONS

The superior portion of the right auricle and basal superoanterior right ventricular myocardium often appear as isolated foci on whole-body Tl-201 and MIBl scans. Neither focus should be interpreted as a metastatic lesion in patients with possible cancer or as an ectopic parathyroid adenoma in patients with hyperparathyroid disease.

Nitric oxide synthase inhibition augments acute allergic reactions in the pig airways in vivo

The aim of this study was to examine the effects of nitric oxide synthase inhibition on antigen- and histamine-induced acute airway reactions, in order to clarify the possible modulating role of NO. Twelve specific-pathogen-free pigs (sensitized with Ascaris suum antigen) were challenged with an antigen aerosol during mechanical ventilation and anaesthesia. Six pigs were pretreated with N(G)-nitro-L-arginine (L-NA, 10 mg x kg(-1)), a NO synthase inhibitor, 30 min before challenge. In separate experiments, seven sensitized pigs received histamine (5 mg) aerosols before and after L-NA treatment. It was found that pretreatment with L-NA resulted in an enhanced airways resistance response to antigen (areas under the curve 0-90 min were (mean+/-SEM) 1,119+/-160 versus 555+/-56 (cmH2O x L(-1) x s(-1) x min for controls, p<0.05 (Mann-Whitney U-test), whereas this response to histamine was not affected by L-NA. Moreover, L-NA pretreatment significantly enhanced total protein (1.85+/-0.43 versus 0.31+/-0.06 g x L(-1), p<0.01) and histamine levels (42.8+/-16.0 versus 2.6+/-0.8 nM, p<0.05) in bronchoalveolar lavage fluid 45 min after antigen challenge. In conclusion, this study showed that N(G)-nitro-L-arginine enhanced reactions occurring during the acute allergic reaction in pigs in vivo. This indicates a protective role of nitric oxide, which might occur through downregulation of histamine release from mast cells rather than a direct bronchodilating effect of nitric oxide.

Effect of cortisol-synthesis inhibition on endotoxin-induced porcine acute lung injury, shock, and nitric oxide production

In the process of developing a model of Escherichia coli endotoxin-induced acute lung injury and shock in specific pathogen-free pigs, the effects of pretreatment with metyrapone (a cortisol-synthesis inhibitor) were examined. Metyrapone was administered 1.5 h before start of endotoxin infusion at t = 0 h (MET-ETOX group, n = 6). At the end of the experiments (t = 4 h) a bronchoalveolar lavage (BAL) was performed. Control animals received only endotoxin (CON-ETOX group, n = 6) or metyrapone (MET-CON group, n = 4). The following results are presented as means +/- SEM. It was found that metyrapone successfully blocked endogenous cortisol synthesis (plasma cortisol levels were 41.0 +/- 5.9 nM in MET-ETOX vs. 339.0 +/- 37.7 nM in CON-ETOX at t = 4 h, P <0.01). At t = 4 h the MET-ETOX animals had substantially increased systemic hypotension compared to the CON-ETOX group (mean arterial pressure 26.7 +/- 4.3 vs. 77.7 +/- 12.2 mmHg, P <0.01), decreased dynamic lung compliance (10.9 +/- 0.7 vs. 13.7 +/- 0.6 ml/cmH2O, P <0.01), increased percentage of BAL neutrophils (28.4 +/- 6.5 vs. 6.6 +/-1.8, P <0.01), pulmonary edema (BAL total protein 0.82 +/- 0.21 vs. 0.42 +/- 0.09 mg/mL, P <0.05), elevated levels of interleukin-8 (1924 +/- 275 vs. 324 +/- 131 pg/mL, P <0.01) and acidosis (pH 7.11 +/- 0.03 vs. 7.23 +/- 0.06, P <0.05). The MET-ETOX group also showed an increased pulmonary hypertension between 2 and 3 h after start of endotoxin infusion and a trend toward significantly increased levels of plasma interleukin-8 (P = 0.052). Arterial pCO2, pO2/FiO2, plasma endothelin-1, plasma TNFalpha, and blood leukocytes were not markedly influenced by the plasma cortisol levels. Nitric oxide production did not seem to be altered by endotoxin infusion in this model, in contrast to other animal studies; this discrepancy could be thought to be due to endotoxin-dosage differences or species differences. It is concluded that if endogenous cortisol production is blocked by metyrapone, the reactions occurring as a result of the endotoxin-induced acute lung injury and shock are greatly enhanced and that therefore pretreatment with metyrapone might be an important addition to this model with specific pathogen-free pigs.

Differential cyclin-dependent kinase expression and activation in human colon cancer

BACKGROUND

Abnormalities of the cyclin-dependent protein kinase (CDK) machinery have been linked to cancer development. Hyperphosphorylation of the retinoblastoma (Rb) protein results in release from inhibition of progression through the G1 phase of the cell cycle. Hyperexpression of CDK1 and CDK2 may enable progression through late G1, S and the G2 phases of the cell cycle.

METHODS/RESULTS

To investigate tumor-associated protein kinase activities, control and tumor samples were fractionated by MonoS chromatography and tested for their ability to phosphorylate histone H1. Two major peaks of histone H1 phosphotransferase activity were resolved. The first appeared in the flow through fractions, and occasionally showed enhanced activity in the tumor samples, whilst the second was consistently increased and eluted at approximately 0.4 M NaCl. Western immunoblotting with CDK1 and PSTAIRE antibodies confirmed the co-elution of CDK1 and CDK2 with the second peak. Next, the phosphotransferase activities (following specific immunoprecipitation) and protein levels of CDK1, 2, 4, and 6 were determined in human colon cancer samples and their respective controls. CDK4 activity was elevated in only 3 of 7 tumor samples (range 40-160%) relative to control samples from the same patients, whereas a significant increase in CDK6 activity was observed in the same group (p < 0.05). This contrasted sharply with the universal activations of CDK1 (up to 18-fold, p < 0.01, n = 12) and CDK2 (up to 17-fold, p < 0.05) in the same groups.

CONCLUSIONS

CDK1 especially, and to a lesser extent CDK2 and CDK6 demonstrate the most consistent biochemical activation in human colon cancer and may represent targets for pharmacological intervention. Cellular proliferation as gauged by MIB1 was not directly correlated with the amplitude of activation.

Tick-host immunology: Significant advances and challenging opportunities

Immunological interactions at the tick-host interface involve innate and acquired host defenses against infestation and immunomodulatory countermeasures by the tick. The cellular and molecular immunological bases of these host-parasite relationships are being defined. Acquired resistance to tick infestation involves humoral and cellular immunoregulatory and effector pathways. Ticks respond by suppressing antibody production, complement, and cytokine elaboration by both antigen-presenting cells and specific T-cell subsets. Tick-borne disease-causing agents probably exploit tick suppression of host defenses during transmission and initiation of infection. Because of the public health importance of ticks and Pick-borne diseases, it is crucial that we understand these interactions and exploit them in novel immunological control strategies. Here, Stephen Wikel and Douglas Bergman discuss recent advances in understanding tick-host immunology and propose future studies.

Thallium-201 and iodine-131 scintigraphy in differentiated thyroid carcinoma

The purpose of this study was to determine the concordance and discordance between diagnostic 131I and 201TI whole-body scintigraphy in patients with differentiated carcinoma of the thyroid.

METHODS

Following thyroidectomy for differentiated thyroid carcinoma, 50 patients underwent whole-body 131I and 201TI scanning (60 pairs of scans in total). Fifteen pairs of studies were obtained before ablative therapy, 30 pairs after ablative therapy and 15 pairs after 131I therapy for metastatic disease. Serum thyroglobulin levels were concurrently determined by radioimmunoassay.

RESULTS

Thirty-six 131I whole-body scans (in 34 patients) showed residual uptake in the neck, but only six (17%) of the corresponding whole-body thallium studies had detectable uptake in the neck. Fourteen 131I scans (in nine patients) identified multiple metastatic lesions, whereas the thallium scans were interpreted as either negative, nonspecific or showing fewer lesions. In four study pairs, the thallium scans showed solitary lesions that were not detected by the corresponding radioiodine scans. In 16 scans, the thallium studies gave false-positive results.

CONCLUSION

Iodine-131 scintigraphy for differentiated thyroid carcinoma is more sensitive and more specific than 201TI scintigraphy for detection of distant metastases and residual activity in the neck following thyroidectomy.

Metastatic calcification of multiple visceral organs in non-Hodgkin's lymphoma

A patient with non-Hodgkin's lymphoma who developed acute hypercalcemia following chemotherapy was evaluated for skeletal metastases with a whole-body bone scan. Although metastatic disease is an unlikely cause of hypercalcemia, considering the acutely rising serum calcium, the bone scan is useful in excluding multiple metastases as a cause. In addition, the study demonstrated metastatic calcification in multiple organs, including the pancreas which is uncommon, and the liver and spleen, which is rare.

Synthesis of alpha 1-antichymotrypsin and alpha 1-antitrypsin by human trophoblast

alpha 1-Antichymotrypsin (alpha 1-ACHY) and alpha 1-antitrypsin (alpha 1-AT) are closely related glycoprotein protease inhibitors, present in plasma and other extracellular fluids, that neutralize proteases released by leukocytes in response to trauma and inflammatory stimuli. Both inhibitors are synthesized primarily by hepatocytes, although lower levels of synthesis by monocytes and breast and intestinal epithelial cells have been demonstrated. Recently, the immunohistochemical localization of alpha 1-AT and alpha 1-ACHY in intrauterine and extrauterine human trophoblastic tissue has been reported. In the present study, we have sought to determine whether human trophoblast is also able to synthesize alpha 1-AT and alpha 1-ACHY. Messenger RNA for both inhibitors was found by Northern blotting in chorionic villi obtained from first trimester and term placenta. Substantial differences in messenger levels for both inhibitors among individual placentas were noted. alpha 1-ACHY and alpha 1-AT messenger was also present in trophoblast cells in primary culture. Synthesis of alpha 1-AT and alpha 1-ACHY protein was demonstrated by SDS-PAGE after immunoprecipitation of [35S]-labeled alpha 1-AT and alpha 1-ACHY from conditioned media of trophoblast cells in culture metabolically labeled with [35S]-methionine. It is of some interest that the M(r) of the alpha 1-AT and alpha 1-ACHY secreted by trophoblast were 50,000 and 49,000, respectively, compared with 54,000 and 68,000 for these proteins in plasma (or secreted by HepG2 human hepatoma and MCF-7 human breast cancer cells).(ABSTRACT TRUNCATED AT 250 WORDS)

Inorganic mercury absorption in mature and immature rat jejunum: transcellular and intercellular pathways in vivo and in everted sacs

The objective of the present work was to test the hypothesis that toxic and nonessential heavy metals in general, and inorganic Hg in particular, are taken up in rat jejunum by a mechanism similar to that previously proposed for Cd. The initiating step in Cd absorption involves electrostatic interaction of the cation with negative membrane charges. In contrast, Hg appears to react with apical membranes as an anion, although overall uptake is not inhibited by the stilbene inhibitor of anion transport DIDS. Further, the ratio of Cd/Hg uptake falls along the jejunum. However, several similarities between Cd and Hg uptakes were observed. Neither process depends on reactive sulfhydryl groups or on oxidative metabolism. Although tissue Hg, unlike Cd, could not be rigorously separated into membrane-bound and intracellular compartments, uptake of both metals includes their relatively temperature-insensitive and rapid influx into a pool readily accessible to suitable extracellular chelators. Another more temperature-sensitive and slower component leads to the filling of a relatively chelation-resistant compartment, identified in the case of Cd as intracellular. Non-specific membrane properties such as surface charge and perhaps membrane fluidity can thus account for mucosal Cd and Hg uptakes; no contribution of specific transport systems need be postulated. Mucosal permeability, calculated in reference to ethanol uptake as measure of absorbing surface area, falls to the same extent for Cd and Hg during postweaning development. Because this fall, however, parallels a diminution in polar diffusion pathways, the mechanism of the faster metal absorption in weanlings may have little bearing on the slower transcellular process in adults. Incidentally, polar diffusion pathways increase in mature jejunum upon preparation of everted sacs, a further limitation on the usefulness of this preparation for the quantitative study of normal intestinal solute transport.

Preoperative parathyroid adenoma localization by the technetium-thallium subtraction scan

The technetium-thallium subtraction scintigram was utilized preoperatively in 14 consecutive patients explored for primary hyperparathyroidism. The scintigram accurately identified the site of a parathyroid adenoma in 12 of 13 patients.

Prevention of acute aspirin-induced gastric mucosal injury by 15-R-15 methyl prostaglandin E2: an endoscopic study

The deleterious effects of aspirin on gastric mucosa have been well documented in experimental and clinical studies. Prostaglandins offer a potential method by which this injury may be prevented. In these studies, we developed a single-dose endoscopic assay system of aspirin-induced gastric mucosal injury in normal volunteers. With this system, 27 of 30 volunteers (90%) demonstrated severe mucosal injury after ingestion of aspirin. Subsequently, we evaluated whether pretreatment with 15-R-15 methyl prostaglandin E2 prevented severe injury after ingestion of aspirin. Following an initial dose-response study, a double-blind crossover trial was performed using pretreatment with placebo or with 10-micrograms doses of 15-R-15 methyl prostaglandin E2 for 24 h before treatment with aspirin. The results of this trial indicate that prostaglandin pretreatment significantly prevented the occurrence of endoscopically visible severe gastric mucosal injury after single-dose aspirin administration.

Glomerulopathy in acute and chronic rejection: relationship of ultrastructure to graft survival

The glomerular ultrastructure was retrospectively reviewed from 45 renal transplant biopsies with the clinical and light microscopic diagnosis of acute rejection (25 cases) and chronic rejection (20 cases). Three grades of morphologic alteration were ultrastructurally defined. In acute rejection, capillary lumenal obliteration with endothelial cell hypertrophy and cellular infiltration were interpreted as the local glomerular expression of the endothelial vascular alterations of acute humoral rejection and were correlated with a poor graft survival. Graft nephrectomy was necessary in 9 of 11 patients with grade III glomerulopathy. In chronic rejection, thickened basement membranes and increased amount of mesangial matrix were considered the result of ischemia. The degree of ultrastructural glomerular alterations in chronic rejection did not correlate with graft survival. Urine protein values were consistently elevated, although poorly correlated with the severity of glomerular alterations. Recurrent glomerulonephritis was not documented in any case. We concluded that the glomerular alteration in acute rejection is a component of acute humoral rejection and that the degree of glomerulopathy in acute rejection is a good predictor of the graft survival.

The effect of hospitalization on intraocular pressure

Thirteen subjects with open-angle glaucoma or ocular hypertension (five men and eight women, ranging in age from 51 to 73 years) were hospitalized for four to six days during which their intraocular pressures were measured four times a day (8 AM, 2 PM, 6 PM, and 10 PM). After leaving the hospital they returned to the outpatient clinic on several occasions for similar measurements (8 AM). Eight patients were taking timolol, pilocarpine, or both and five were receiving no treatment. In all cases, the 8 AM measurement was lower during hospitalization. The difference between the two sets of measurements was significant at P = .021.

Human rectal mucosa: proctoscopic and morphological changes caused by laxatives

To determine whether laxatives alter the proctoscopic and morphological appearances of the human rectum, 10 normal subjects were studied prospectively, and the following manipulations were assessed in a randomized, blinded manner: no treatment; oral mannitol to induce diarrhea; isotonic saline enema; Fleet's Phospho-Soda enema; and bisacodyl (Dulcolax), 10 mg, by enema or suppository. The rectal mucosa after mannitol-induced diarrhea, or after saline enema could not be distinguished from untreated rectum by proctoscopy, light microscopy, or scanning electron microscopy. Fleet's enema, and bisacodyl invariably changed proctoscopic appearances, and frequently altered light and scanning microscopic aspects. Both Fleet's enema and bisacodyl caused sloughing of surface epithelium. In addition, bisacodyl decreased the uptake of hematoxylin and eosin by crypt epithelial cells so that the affected cells had a partially erased appearance (16 of 25 biopsies examined by light microscopy). The lamina propria of 3 of these 25 biopsies contained polymorphonuclear cells. Transmission electron microscopy revealed that the abnormal crypt epithelial cells contained fewer cytoplasmic organelles and less nuclear chromatin. All lesions resolved within 7 days. Fleet's enema and bisacodyl by rectum may mislead the proctologist and the pathologist by altering normal rectal mucosa.