Enzymatic, clinical and histologic evaluation of corneal tissues in experimental fungal keratitis in rabbits

Mycotic keratitis, being frequently refractive to most of the currently available antifungal therapy, continues to pose a therapeutic challenge to the clinician. In keratitis of infectious etiology stromal dissolution may be brought about by a combination of agent and host factors. An understanding of the source and nature of corneal tissue damage is essential for evolving more effective therapeutic modalities in the treatment of fungal keratitis. In the present study, we have characterized the extracellular proteases produced in vitro by corneal fungal pathogens namely the Aspergillus flavus and Fusarium solani when collagen was provided as the sole nitrogen source. In addition, fungal infected rabbit corneas were investigated for proteolytic activities and nature of inflammatory reaction. Gelatin zymography detected protease bands with molecular mass ranging from 100 to 200 kDa in the culture extracts of A. flavus, and a single major band of molecular mass approximately 200 kDa in the culture extracts of F. solani. A basal proteolytic activity of mass 65 kDa was visualized in all uninfected and infected rabbit corneal extracts. Infected corneas in addition revealed the presence of additional proteolytic species of mass 92 and 200 kDa. The enzyme inhibitory profile suggested that fungal cultures in vitro contained predominantly serine protease activity and to a lesser extent metalloprotease activity. However, fungal infected corneal homogenates showed the presence of metalloproteinase activity alone, the enzymatic activities entirely being sensitive to ethylene diamine tetra acetate (EDTA), a metalloprotease inhibitor. Interestingly, the serine proteolytic activity detected in fungal cultures in vitro was not present in the fungal infected corneas in vivo. However, the possible role of fungal serine proteases in the activation of corneal matrix metalloproteinases (MMPs) cannot be ruled out. Based on the criteria of molecular mass, proteolytic activity in the presence of calcium at neutral pH, and sensitivity to inhibition by a metalloprotease inhibitor, the 65 and 92 kDa gelatinases were identified as MMP 2 and MMP 9, respectively. The expression of 92 and 200 kDa gelatinases correlated positively with the amount of polymorphonuclear cells present in the infected tissues. Activated resident corneal cells or inflammatory cells may largely contribute to the increased proteolytic activities in fungal infected corneas resulting in tissue matrix degradation in fungal keratitis.

Prediction of eye irritation from organic chemicals using membrane-interaction QSAR analysis

Eye irritation potency of a compound or mixture has traditionally been evaluated using the Draize rabbit-eye test (Draize et al., 1944). In order to aid predictions of eye irritation and to explore possible corresponding mechanisms of eye irritation, a methodology termed "membrane-interaction QSAR analysis" (MI-QSAR) has been developed (Kulkarni and Hopfinger 1999). A set of Draize eye-irritation data established by the European Center for Ecotoxicology and Toxicology of Chemicals (ECETOC) (Bagley et al., 1992) was used as a structurally diverse training set in an MI-QSAR analysis. Significant QSAR models were constructed based primarily upon aqueous solvation-free energy of the solute and the strength of solute binding to a model phospholipid (DMPC) monolayer. The results demonstrate that inclusion of parameters to model membrane interactions of potentially irritating chemicals provides significantly better predictions of eye irritation for structurally diverse compounds than does modeling based solely on physiochemical properties of chemicals. The specific MI-QSAR models reported here are, in fact, close to the upper limit in both significance and robustness that can be expected for the variability inherent to the eye-irritation scores of the ECETOC training set. The MI-QSAR models can be used with high reliability to classify compounds of low- and high-predicted eye irritation scores. Thus, the models offer the opportunity to reduce animal testing for compounds predicted to fall into these two extreme eye-irritation score sets. The MI-QSAR paradigm may also be applicable to other toxicological endpoints, such as skin irritation, where interactions with cellular membranes are likely.

Glycolipid antigen processing for presentation by CD1d molecules

The requirement for processing glycolipid antigens in T cell recognition was examined with mouse CD1d-mediated responses to glycosphingolipids (GSLs). Although some disaccharide GSL antigens can be recognized without processing, the responses to three other antigens, including the disaccharide GSL Gal(alpha1-->2)GalCer (Gal, galactose; GalCer, galactosylceramide), required removal of the terminal sugars to permit interaction with the T cell receptor. A lysosomal enzyme, alpha-galactosidase A, was responsible for the processing of Gal(alpha1-->2)GalCer to generate the antigenic monosaccharide epitope. These data demonstrate a carbohydrate antigen processing system analogous to that used for peptides and an ability of T cells to recognize processed fragments of complex glycolipids.

Genetic dissection of the olfactory bulbs of mice: QTLs on four chromosomes modulate bulb size

Olfaction is influenced by a complex mix of environmental and genetic factors that modulate the production, migration, and maturation of cells in the olfactory bulbs. In this study we analyzed effects of sex, age, body weight, and brain weight on olfactory bulb size in sexually mature mice. We then used regression corrected values (residuals) to map quantitative trait loci (QTLs) that selectively modulate bulb weight. This biometric analysis has relied on an F2 intercross between C57BL/6J (B6) and DBA/2J (D2) inbred strains and a large sample of 35 BXD recombinant inbred (RI) strains. Bilateral bulb weight in adult mice ranges from 10 to 30 mg. Half of this remarkable variation can be predicted from differences in brain weight, sex, body weight, and age. A 100-mg difference in brain weight is associated with a 4.4-mg difference in bulb weight. Bulbs gain in weight by 0.2 mg/week--a 1% increase that continues until at least 300 days of age. Males tend to have slightly larger bulbs than females. By combining data from both related crosses (F2 and RI) we identified four QTLs with selective effects on bulb size (genomewide p < .05). Bulb4a is located on chromosome 4 (Chr 4) and Bulb6a is located on Chr 6. Alleles inherited from B6 at both of these loci increase bulb weight by 0.5-1.0 mg. Bulb11a is located on proximal Chr 11 and Bulb17a is located on the proximal part of Chr 17. In contrast to the first two QTLs, B6 alleles at these two loci decrease bulb weight by 0.5-1.0 mg. Collectively, the four loci account for 20% of the phenotypic variance in bulb weight.

Reduction of globotriaosylceramide in Fabry disease mice by substrate deprivation

We used a potent inhibitor of glucosylceramide synthase to test whether substrate deprivation could lower globotriaosylceramide levels in alpha-galactosidase A (alpha-gal A) knockout mice, a model of Fabry disease. C57BL/6 mice treated twice daily for 3 days with D-threo-1-ethylendioxyphenyl-2-palmitoylamino-3-pyrrolidi no-propanol (D-t-EtDO-P4) showed a concentration-dependent decrement in glucosylceramide levels in kidney, liver, and spleen. A single intraperitoneal injection of D-t-EtDO-P4 resulted in a 55% reduction in renal glucosylceramide, consistent with rapid renal glucosylceramide metabolism. A concentration-dependent decrement in renal and hepatic globotriaosylceramide levels was observed in alpha-Gal A(-) males treated for 4 weeks with D-t-EtDO-P4. When 8-week-old alpha-Gal A(-) males were treated for 8 weeks with 10 mg/kg twice daily, renal globotriaosylceramide fell to below starting levels, consistent with an alpha-galactosidase A-independent salvage pathway for globotriaosylceramide degradation. Complications observed with another glucosylceramide synthase inhibitor, N-butyldeoxynojirimycin, including weight loss and acellularity of lymphatic organs, were not observed with D-t-EtDO-P4. These data suggest that Fabry disease may be amenable to substrate deprivation therapy.

Histiocytosis presenting as a nasal mass

The authors present a 1-year-old child who presented with an expansile enhancing mass of the nasal cavity that proved to be histiocytosis.

Mohr syndrome: a rare case and distinction from orofacial digital syndrome 1

In view of the different modes of inheritance and the different prognoses of the two oro-facio-digital syndromes, type 1 and type 2, it is important to establish a correct diagnosis in these patients. A case of type II oro-facio-digital syndrome is being reported and the distinguishing clinicoradiological features with type I are compared.

Heterogeneity of coronary heart disease risk factors in Indian, Pakistani, Bangladeshi, and European origin populations: cross sectional study

OBJECTIVE

To compare coronary risk factors and disease prevalence among Indians, Pakistanis, and Bangladeshis, and in all South Asians (these three groups together) with Europeans.

DESIGN

Cross sectional survey.

SETTING

Newcastle upon Tyne.

PARTICIPANTS

259 Indian, 305 Pakistani, 120 Bangladeshi, and 825 European men and women aged 25-74 years.

MAIN OUTCOME MEASURES

Social and economic circumstances, lifestyle, self reported symptoms and diseases, blood pressure, electrocardiogram, and anthropometric, haematological, and biochemical measurements.

RESULTS

There were differences in social and economic circumstances, lifestyles, anthropometric measures and disease both between Indians, Pakistanis, and Bangladeshis and between all South Asians and Europeans. Bangladeshis and Pakistanis were the poorest groups. For most risk factors, the Bangladeshis (particularly men) fared the worst: smoking was most common (57%) in that group, and Bangladeshis had the highest concentrations of triglycerides (2.04 mmol/l) and fasting blood glucose (6.6 mmol/l) and the lowest concentration of high density lipoprotein cholesterol (0.97 mmol/l). Blood pressure, however, was lowest in Bangladeshis. Bangladeshis were the shortest (men 164 cm tall v 170 cm for Indians and 174 cm for Europeans). A higher proportion of Pakistani and Bangladeshi men had diabetes (22.4% and 26.6% respectively) than Indians (15.2%). Comparisons of all South Asians with Europeans hid some important differences, but South Asians were still disadvantaged in a wide range of risk factors. Findings in women were similar.

CONCLUSION

Risk of coronary heart disease is not uniform among South Asians, and there are important differences between Indians, Pakistanis, and Bangladeshis for many coronary risk factors. The belief that, except for insulin resistance, South Asians have lower levels of coronary risk factors than Europeans is incorrect, and may have arisen from combining ethnic subgroups and examining a narrow range of factors.

Role of ethamsylate in preventing periventricular-intraventricular hemorrhage in premature infants below 34 weeks of gestation

OBJECTIVE

To determine the role of ethamsylate in prevention of PVH-IVH in premature infants <34 weeks gestational age.

DESIGN

Prospective, randomized, controlled study.

METHODS

Infants less than 34 weeks gestational age were included in the trial. Neonates with congenital malformations, family history of bleeding disorders and with Apgar scores <5 at 5 minutes were excluded. Subjects were randomized into two groups--Group A infants received intravenous ethamsylate (12.5 mg/kg) six hourly for four days and Group B infants served as a control group. Regular cranial ultrasounds to detect the presence of PVH-IVH were done between days 3-5, 10-14 and 28-30 of post natal age, and before hospital discharge in all infants and weekly in infants detected to have PVH-IVH on earlier scans. Various antenatal and postnatal factors known to affect the incidence of PVH-IVH were recorded.

RESULTS

A total of 192 infants underwent the trial, 93 in Group A and 99 in Group B. Antenatal corticosteroids (1 or 2 doses) were administered to 32 ( 34.4%) and 36 (36.3%) women in Group A and Group B, respectively. None of the mothers received phenobarbitone, vitamin K or indomethacin antenatally and none of the infants received phenobarbitone, vitamin E or indomethacin postnatally during the study period. PVH-IVH was seen in 26 infants in Group A, of which Grade I IVH occurred in 9, Grade II in 14, Grade III in 2 and Grade IV in one infant. Twenty-nine infants had PVH-IVH in Group B of which 11 had Grade I, 15 Grade II and 3 Grade III. None of the differences were statistically significant.

CONCLUSION

Postnatal administration of ethamsylate did not decrease the incidence of PVH-IVH in the study infants.

Sensitivity of human subjects to head-related transfer-function phase spectra

Head-related transfer functions (HRTFs) for human subjects in anechoic space were modeled with modified phase spectra, including minimum-phase-plus-delay, linear-phase, and reversed-phase-plus-delay functions. The overall (wide-band) interaural time delay (ITD) for the modeled HRTFs was made consistent with that of the empirical HRTFs by setting the position-dependent, frequency-independent delay in the HRTF for the lagging ear. Signal analysis of the minimum-phase-plus-delay reconstructions indicated that model HRTFs deviate from empirical HRTF measurements maximally for contralateral azimuths and low elevations. Subjects assessed the perceptual validity of the model HRTFs in a four-interval, two-alternative, forced-choice discrimination paradigm. Results indicate that monaural discrimination performance of subjects was at chance for all three types of HRTF models. Binaural discrimination performance was at chance for the linear-phase HRTFs, was above chance for some locations for the minimum-phase-plus-delay HRTFs, and was above chance for all tested locations for the reversed-phase-plus-delay HRTFs. An analysis of low-frequency timing information showed that all of these results are consistent with efficient use of interaural time differences in the low-frequency components of the stimulus waveforms. It is concluded that listeners are insensitive to HRTF phase spectra as long as the overall ITD of the low-frequency components does not provide a reliable cue. In particular, the minimum-phase-plus-delay approximation to the HRTF phase spectrum is an adequate approximation as long as the low-frequency ITD is appropriate. These results and conclusions are all limited to the anechoic case when the HRTFs correspond to brief impulse responses limited to a few milliseconds.

Role of spectral detail in sound-source localization

Sounds heard over headphones are typically perceived inside the head (internalized), unlike real sound sources which are perceived outside the head (externalized). If the acoustical waveforms from a real sound source are reproduced precisely using headphones, auditory images are appropriately externalized and localized. The filtering (relative boosting, attenuation and delaying of component frequencies) of a sound by the head and outer ear provides information about the location of a sound source by means of the differences in the frequency spectra between the ears as well as the overall spectral shape. This location-dependent filtering is explicitly described by the head-related transfer function (HRTF) from sound source to ear canal. Here we present sounds to subjects through open-canal tube-phones and investigate how accurately the HRTFs must be reproduced to achieve true three-dimensional perception of auditory signals in anechoic space. Listeners attempted to discriminate between 'real' sounds presented from a loudspeaker and 'virtual' sounds presented over tube-phones. Our results show that the HRTFs can be smoothed significantly in frequency without affecting the perceived location of a sound. Listeners cannot distinguish real from virtual sources until the HRTF has lost most of its detailed variation in frequency, at which time the perceived elevation of the image is the reported cue.

Phenotypic consequences of transforming growth factor beta1 gene ablation in murine embryonic fibroblasts: autocrine control of cell proliferation and extracellular matrix biosynthesis

The profound effects of transforming growth factor beta1 (TGF-beta1) on the immune system, cardiogenesis, in yolk sac hematopoeisis and in differentiation of endothelium have been demonstrated by detailed analyses of TGF-beta1 knockout mice during embryogenesis. We have systematically examined the autocrine and paracrine roles of TGF-beta1 in cell proliferation and in its ability to modulate the gene expression of selected components of extracellular matrix (ECM) using embryonic fibroblasts from TGF-beta1 null mice (TGF-beta-1(-/-)). The rates of cell proliferation of embryonic fibroblasts from normal mice (TGF-beta1(+/+)) and TGF-beta1 null mice were compared by cell counting, by 3H thymidine incorporation, and by measuring the fraction of cells in the G1, S, and G2/M phases of the cell cycle by fluorescent activated cell sorting (FACS). Concurrently, the expression of pro-alpha1(I) collagen, fibronectin, and plasminogen activator inhibitor-1 (PAI-1) was also quantified by hybridization of total mRNA from TGF-beta1(+/+) and TGF-beta1(-/-) embryonic fibroblasts. We report that TGF-beta1(-/-) cells proliferated at about twice the rate of TGF-beta1(+/+) cells. Further, TGF-beta1 null fibroblasts accumulated and synthesized lower constitutive levels of pro-alpha1(I) collagen, fibronectin, and PAI-1 mRNA. The quantitative differences in the rates of cell proliferation and ECM gene expression between TGF-beta1(+/-) and TGF-beta1(-/-) cells could be eliminated by treatment of TGF-beta1(+/+) cells with a neutralizing antibody of TGF-beta1. Thus, our results are consistent with the hypothesis that TGF-beta1 acts as a negative autocrine regulator of growth and a positive autocrine regulator of ECM biosynthesis in embryonic fibroblasts.

Nutritional supplementation of nucleotides restores opioid CNS-mediated phenomena in mice

Previous experiments have demonstrated that suppression of immune function by either cyclosporin A or by a nucleotide free (NF) diet results in attenuation of morphine withdrawal symptoms in mice suggesting that immune status impacts CNS opioid-related phenomena. The present study elaborates on these initial findings by examining the effects of repletion of the NF diet with nucleotides or their precursors on opiate withdrawal. Female Balb/c mice were divided into six groups: a control group (C) given a standard lab chow diet and five experimental groups each given one of the following diets: a nucleotide free diet (NF); the NF supplemented with 0.25% RNA (NFR 0.25); the NF supplemented with 2.5% RNA (NFR 2.5) the NF supplemented with 0.06% uracil (NFU 0.06); the NF supplemented with 0.6% uracil (NFU 0.6). The mice were made morphine dependent by subcutaneous implantation of morphine pellets. Seventy-two hours after morphine pellet implantation, withdrawal was precipitated with naloxone (2 mg/kg). The mice were then observed and two indicators of withdrawal scored: jumping and diarrhea. The NF, NFR 0.25, NFR 2.5 and NFU 0.06 groups demonstrated significantly attenuation of the withdrawal signs relative to control animals. The NFU 0.6 group, however, had withdrawal scores restored to near control levels for both jumping and diarrhea. This suggests that nucleotides, particularly uracil, may play an important role in the immune-to-brain signaling pathway.

Nucleoside-nucleotide-free diet suppresses cytokine production and contact sensitivity responses in rats with trinitrobenzene sulphonic acid-induced colitis

We examined the effects of dietary nucleoside-nucleotide mixture on synthesis of inflammatory cytokines, interleukin-8 and tumor necrosis factor-alpha, in sensitized and nonsensitized colitic rats. Sensitized and nonsensitized colitic rats that were fed a nucleoside-nucleotide mixture had greater colonic weight and macroscopic and microscopic damage scores than nucleoside-nucleotide-free sensitized and nonsensitized colitic rats. Increased colonic tumor necrosis factor-alpha and interleukin-8 concentrations were associated with increased colonic inflammation and ulceration in the nucleoside-nucleotide mixture-fed group. There was also increased ear thickness in the nucleoside-nucleotide mixture-fed sensitized and nonsensitized colitic rats, which correlated highly with increased tumor necrosis factor-alpha and interleukin-8 levels in the ear lobes. Nucleoside-nucleotide-free diets may suppress cytokine secretion, thereby reducing colonic damage and contact sensitivity responses in colitic rats.

Pseudocysts of pancreas in children

A total of 7 patients pseudopancreatic cysts was managed in children over a period of 5 years. Trauma was responsible for the development of pseudocyst in one while in rest of the patients no etiologic factor could be identified. All the patients underwent trans-gastric cyctogastrostomy. With a mean follow-up of 30 months, no death and no recurrence was found. It seems that surgical experience of pseudopancreatic cysts in children is similar to that seen in adults.

Pseudocysts of pancreas in children

A total of 7 patients of pseudopancreatic cysts was managed in children over a period of 5 years Trauma was responsible for the development of pseudocyst in one while in rest of the patients no etiologic factor could be identified. All the patients underwent transgastric cystogastrostomy. With a mean follow-up of 30 months, no death and no recurrence was found. It seems that surgical experience of pseudopancreatic cysts in children is similar to that seen in adults.

Coronary angioplasty in unstable angina: contemporary experience

OBJECTIVE

To evaluate the role of percutaneous transluminal coronary angioplasty (PTCA) in the treatment of patients with unstable angina.

DESIGN

Retrospective analysis of administrative records of all acute care hospital discharges at Robert Wood Johnson University Hospital from 1987 to 1993 with International Classification of Diseases, 9th revision, codes for coronary angioplasty and corresponding catheterization laboratory reports.

SETTING

Tertiary care teaching hospital.

RESULTS

Of 4826 PTCA cases, unstable angina was identified in 780 as the main indication for the procedure. Baseline clinical features of patients with unstable angina were not different from those in patients with stable angina. The overall success rate for PTCA in patients with unstable angina was significantly higher (707 of 780, 91%) than the success rate in patients with stable angina (3466 of 4046, 86%). The major complication rate in unstable angina patients was low (29 of 780, 3.7%) and did not differ from that in stable angina patients (136 of 4046, 3.4%). The success and complication rates in patients with unstable angina were analyzed in terms of time of PTCA, ie, early (less than 48 h from admission) versus late (48 h or more from admission). The procedure was successful in 343 of 380 (90%) patients treated early and 364 of 400 (91%) patients treated late (not significant), and the complication rates were low (12 of 380, 3.2% versus 17 of 400, 4.3%; not significant in both groups). However, length of hospital stay was considerably shorter for patients treated early than for patients treated late (4.5 +/- 3.3 days versus 10.4 +/- 6.6 days, respectively, P < 0.0001).

CONCLUSION

Contemporary results of PTCA in patients with unstable angina parallel those reported for stable angina. Thus, PTCA appears to be an effective and safe treatment for unstable angina patients, and treating these patients soon after admission does not appear to affect the success or complication rates.

Influence of autoregressive model parameter uncertainty on spectral estimates of heart rate dynamics

Linear autoregressive (AR) model-based heart rate (HR) spectral analysis has been widely used to study HR dynamics. Owing to system and measurement noise, the parameters of an AR model have intrinsic statistical uncertainty. In this study, we evaluate how this AR parameter uncertainty can translate to uncertainty in HR power spectra. HR time series, obtained from seven subjects in supine and standing positions, were fitted to AR models by least squares minimization via singular value decomposition. Spectral uncertainty due to inexact parameter estimation was assessed through a Monte Carlo study in which the AR model parameters were varied randomly according to their Gaussian distributions. Histogram techniques were used to evaluate the distribution of 50,000 AR spectral estimates of each HR time series. These Monte Carlo uncertainties were found to exceed those predicted by previous theoretical approximations. It was determined that the uncertainty of AR HR spectral estimates, particularly the locations and magnitudes of spectral peaks, can often be large. The same Monte Carlo analysis was applied to synthetic AR time series and found levels of spectral uncertainty similar to that of the HR data, thus suggesting that the results of this study are not specific to experimental HR data. Therefore, AR spectra may be unreliable, and one must be careful in assigning pathophysiological origins to specific spectral features of any one spectrum.

Nucleic acids and/or their components: a possible role in immune function

Dietary sources of nucleic acids and/or their components, have not been considered essential for normal growth and development. However, growing evidence shows that the compounds regulate various steps of the immune system and demonstrate the necessity of the compounds in the response to immunological challenge. The significance of exogenously administered purine or pyrimidine bases, nucleotides, and nucleosides in the immune response is reviewed.

Platelet-activating factor mediates trinitrobenzene induced colitis

Platelet-activating factor (PAF) is an endogenous phospholipid which may be an important mediator of shock and inflammation. Recent evidence suggests that PAF plays a role in the development of ischemic colitis and inflammatory bowel disease. Its effects are mediated by second messengers, including the arachidonic acid metabolites. Using an ex vivo isolated left colon rabbit perfusion model, our aims were to determine whether exogenously administered trinitrobenzene sulfonic acid (TNB), which produces experimental colitis, stimulates both PAF and eicosanoid release in the colon, and if so, whether this effect can be blocked by a PAF antagonist. Colonic inflammation was induced by the intracolonic administration of 0.25 ml of 50% ethanol containing 30 mg of TNB. Tissue and perfusate concentrations of the eicosanoids, [prostaglandin E (PGE2), 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) and thromboxane B2 (TXB2), leukotriene B4 (LTB4)] and the autocoid PAF were measured by ELISA. During TNB infusion there was a significant increase in tissue levels of PAF compared to control colons. Additional studies performed pretreating the colons with the PAF receptor antagonist WEB-2170 prior to TNB infusion blocked PAF release. TNB stimulated release of luminal eicosanoids except LTB4 and suppressed release of tissue prostanoids. Pretreatment with WEB-2170 prior to TNB inhibited luminal eicosanoids, and inhibited PGE2 and prostacyclin, but not TX tissue suppression. Inhibition of TNB-stimulated PAF release by WEB-2170 suggests that PAF may play a role in TNB-induced colitis and this phenomenon may mediate tissue injury.

Salt-tolerant and thermostable alkaline protease from Bacillus subtilis NCIM no. 64

The proteolytic activity produced by a Bacillus subtilis isolated from a hot spring was investigated. Maximum protease production was obtained after 38 h of fermentation. Effects of various carbon and nitrogen sources indicate the requirement of starch and bacteriological peptone to be the best inducers for maximum protease production. Requirement for phosphorus was very evident, and the protease was secreted over a wide range of pH 5-11. The partially purified enzyme was stable at 60 degrees C for 30 min. Calcium ions were effective in stabilizing the enzyme, especially at higher temperature. The enzyme was extremely salt tolerant and retained 100% activity in 5M NaCl over 96 h. The molecular weight of the purified enzymes as determined by SDS-PAGE was 28,000. The enzyme was completely inactivated by PMSF, but little affected by urea, sodium dodecyl sulfate, and sodium tripoly phosphate.

Rat hepatic glutathione S-transferase-mediated embryotoxic bioactivation of ethylene dibromide

The embryotoxic effects of ethylene dibromide (EDB) bioactivation, mediated by purified rat liver glutathione S-transferases (GST), were investigated using rat embryos in culture. Significant EDB metabolism was observed with rat liver GST purified by affinity chromatography (specific activity of 188 +/- 11.3 nmol/min/mg protein). The reaction was enzymatic in nature and the conjugation rate was proportional to the concentration of EDB (up to 0.75 mM) and the enzyme present in the reaction medium. EDB activation by 100 units (1 unit = 1 nmol of glutathione consumed per min) of purified rat liver GST caused a significant reduction in general development as measured by crown-rump length, yolk sac diameter, somite number, and the composite score for different morphological parameters (Brown and Fabro methodology). Structures most significantly affected were the central nervous and olfactory systems as well as the yolk sac circulation and allantois. The results of this study clearly indicate that under in vitro conditions, bioactivation of EDB by GST can lead to embryotoxicity.

Inhibition of human term placental and fetal liver glutathione-S-transferases by fatty acids and fatty acid esters

Glutathione-S-transferase (GST) activity from human term placenta and human fetal liver towards 1-chloro-2,4-dinitrobenzene as the second substrate was significantly inhibited by the saturated fatty acids, stearic (SA) and palmitic (PA) acids and fatty acid esters, ascorbyl stearate (Asc-S) and ascorbyl palmitate (Asc-P). The nature of inhibition of human placental GST was competitive towards CDNB with Ki values of 3.1, 10.0, 13.5 and 18.5 microM for Asc-S, Asc-P, PA and SA, respectively. The inhibitory effect of Asc-S on human term placental GST was reversible. I50 values for Asc-S, Asc-P, SA and PA were 15, 45, 83 and 78 microM, respectively, for partially purified human fetal liver GSTs and 21, 6, 88 and 117 microM, respectively, for partially pure rat liver GSTs. The evidence suggests that Asc-S, Asc-P, SA and PA are potent inhibitors especially of the pi-class of GST.

A novel model to assess developmental toxicity of dihaloalkanes in humans: Bioactivation of 1,2-dibromoethane by the isozymes of human fetal liver glutathione S-transferase

Glutathione S-transferase (GST) isozymes from human fetal liver (16-18 weeks gestation) were purified by affinity chromatography followed by ion-exchange high performance liquid chromatography (HPLC). The purified isozymes were used to investigate toxicity of 1,2-dibromoethane(EDB) in an in vitro model of rat embryos in culture as passive targets. At least five isozymes of GST were found in the human fetal liver. Two anionic forms [pI values 5.5 (P-2) and 4.5 (P-3)] and one basic form [pI value 8.7 (P-6)] were clearly separated. The presence of two near-neutral forms was also identified. All the isozymes of the human fetal liver GSTs tested metabolized EDB (specific activities were 2.1, 7.0, and 2.0 mumol of GSH consumed/min/mg protein for P-2, P-3, and P-6 isozymes, respectively). Covalent binding of EDB to DNA and protein was 144% and 212% higher, respectively, with the P-3 anionic isozyme when compared to the P-6 basic isozyme of GST. No covalent binding to either protein or DNA was observed with the P-2 isozyme. EDB bioactivation by the GST isozyme P-3 (15 units; 1 unit = 1 nmol of GSH consumed/min) resulted in toxicity to cultured rat embryos. Significant reductions of crown rump length, yolk sac diameter, and the composite score of morphological parameters (Brown and Fabro method) were observed. The central nervous system, optic and olfactory systems, and the hind limb were most significantly affected. The results of this investigation suggest that EDB may be classified as a suspected developmental toxicant in humans.

Azelastine and desmethylazelastine suppress acetylcholine-induced contraction and depolarization in human airway smooth muscle

We examined the effects of a new anti-asthmatic drug, azelastine, and its principal metabolite, desmethylazelastine, on the in vitro electromechanical response of human airway smooth muscle during cholinergic stimulation. Membrane potential and isometric force were simultaneously measured using an intracellular microelectrode and a microforce transducer. Desmethylazelastine significantly suppressed acetylcholine-induced depolarization and contraction at 10(-6) M, whereas azelastine produced similar results at 10(-4) M, suggesting that the metabolite may be the principal compound acting upon the airway smooth muscle cell.

Occult spinal dysraphism: clinical and urodynamic outcome after division of the filum terminale

A highly select group of 31 patients presenting with urinary incontinence failed to respond to conservative management and were found to have unstable bladders and spina bifida occulta. After thorough evaluation they were suspected of having neurogenic bladder dysfunction possibly due to a tethered cord. Following division of the filum terminale daytime incontinence resolved in 72%, urodynamic detrusor hyperreflexia disappeared in 59% and bladder compliance improved in 66% of the patients. The operation was well tolerated and did not result in any neurological complications. The clinical, radiological and urodynamic characteristics of these patients before and after treatment are reported.

Hemodynamic effects of dilevalol in patients with systemic hypertension and left ventricular dysfunction

Hemodynamic and left ventricular function parameters were measured in patients with mild to moderate hypertension and compromised left ventricular function who were given dilevalol, an antihypertensive agent with selective beta 2-agonism and nonselective beta-antagonist activity. After a 2- to 3-week placebo washout period, 9 patients were given dilevalol titrated upward from 100 to 600 mg twice daily over a 7-week period to achieve a supine diastolic blood pressure of less than 90 mm Hg with a decrease of greater than or equal to 10 mm Hg from baseline. Multigated radionuclide ventriculography and systolic and diastolic time intervals were performed after the pretreatment placebo washout, at the end of 2 weeks' maintenance dosing, and after a 7- to 10-day post-treatment discontinuation and placebo washout period. At an average daily dose of dilevalol, 444 mg, heart rate at rest decreased significantly (p less than 0.01) during treatment and increased during post-treatment placebo. Systolic and diastolic blood pressures at rest decreased significantly (p less than 0.01) during treatment and increased during post-treatment placebo. At maximal exercise, changes in blood pressure and heart rate were significantly blunted (p less than 0.05) during treatment. Ejection fraction at rest increased significantly (p less than 0.01) during treatment, with no significant change occurring during exercise, and decreased during post-treatment placebo. Preejection period decreased significantly during treatment (p less than 0.005) and increased during post-treatment placebo.(ABSTRACT TRUNCATED AT 250 WORDS)

Suppression of opiate withdrawal by cyclosporin A and dietary modification

It has been demonstrated in a murine model that a defined diet (Purina Basal Diet 5755) has immunosuppressive effects similar to cyclosporin A (CsA). It was also shown that CsA treatment in opiate dependent rats can attenuate the severity of opiate withdrawal. In this study, an opiate dependence model was established in Balb/c mice to assess the effects of the 5755 diet and CsA on morphine withdrawal - a CNS mediated phenomenon. Three groups of mice were used; a chow-fed control group (Purina 5008), a chow fed CsA treated group, and a group maintained on the 5755 diet. Morphine dependence was established by subcutaneous implantation of a 100 mg morphine base pellet under ether anesthesia. Seventy-two hours after pellet implantation, withdrawal was precipitated by a single injection of the opiate antagonist naloxone (2 mg/kg ip). Two indicators of withdrawal were assessed; jumping and diarrhea. The data demonstrated that both CsA and the 5755 diet resulted in significant attenuation of withdrawal symptoms with the 5755 diet being the most effective of the two. These findings suggest that immune modulation elicited by the 5755 diet and CsA treatment has a direct impact on the CNS opioid function.

A moderate concentration of ethanol alters cellular membrane potentials and decreases contractile force of human fetal heart

The effects of ethanol, although well studied in the adult myocardium, have been little studied in fetal tissue. Experiments in pregnant animals suggest that ethanol compromises fetal myocardial performance, in utero; however, the physiological mechanism(s) remains obscure. The present report examines, in vitro, the effects of a moderate concentration of ethanol (20 mM) directly on cell membrane potentials and contractility of human fetal left ventricle as determined using intracellular microelectrodes and microforce transducers. We observed significant decreases in action potential amplitude, upstroke velocity, duration of repolarization, and the force of contractions. These effects were reversible. As ethanol crosses the placenta, our findings suggest that moderate concentrations of ethanol, as occur during 'social drinking', may temporarily compromise fetal myocardial performance in utero.

Dexamethasone suppression test, schizophrenia and movement disorder

The dexamethasone suppression test (DST) was administered to 20 patients with schizophrenic illness. Ten of these patients also had tardive dyskinesia (TD). The scores on TD and parkinsonism scales were significantly higher in DST nonsuppressors. There was also a significant positive correlation between the post-dexamethasone cortisol level and the movement disorder scales.