Combined effect of Photorhabdus luminescens and Bacillus thuringiensis subsp. aizawai on Plutella xylostella.

In this study, we evaluated a new biopesticide containing different combinations of Photorhabdus luminescens (ATCC 29,999; Pl) and Bacillus thuringiensis subsp. aizawai (Bt) to leverage their insecticidal activity against Plutella xylostella. Mixtures containing proteins of various sizes were assayed to determine which combination of the two bacteria would yield the maximum insecticidal activity. A histopathologic slide revealed vacuole formations and rifts near the apical membrane (a symptom of Bt) and severe thinning of the intestinal wall (a symptom of Pl). When the two bacteria were cultured separately and then mixed, the insecticidal activity of the treatment reached 83.33% ± 8.82%. The insecticidal activity was elevated and significantly accelerated when Bt was mixed with both the Pl supernatant and the isolated protein with a molecular mass [Formula: see text] 100 kDa of Pl. These results highlight the potential of Pl as a potent bioinsecticide to economically and sustainably control Pl. xylostella and other lepidopteran pests. KEY POINTS: • Growth inhibition by Bacillus thuringiensis exerted a significant effect on insecticidal activity. • Large Photorhabdus luminescens proteins can accelerate the synergistic insecticidal effect on Plutella xylostella.

DNA extraction method influences human milk bacterial profiles.

AIMS: To evaluate four DNA extraction methods to elucidate the most effective method for bacterial DNA recovery from human milk (HM). METHODS AND RESULTS: Human milk DNA was extracted using the following methods: (i) Qiagen MagAttract Microbial DNA Isolation Kit (kit QM), (ii) Norgen Milk Bacterial DNA Isolation Kit (kit NM), (iii) Qiagen MagAttract Microbiome DNA/RNA Isolation Kit (kit MM) and (iv) TRIzol LS Reagent (method LS). The full-length 16S rRNA gene was sequenced. Kits MM and method LS were unable to extract detectable levels of DNA in 9/11 samples. Detectable levels of DNA were recovered from all samples using kits NM (mean = 0·68 ng µl-1 ) and QM (mean = 0·55 ng µl-1 ). For kits NM and QM, the greatest number of reads were associated with Staphylococcus epidermidis, Streptococcus vestibularis, Propionibacterium acnes, Veillonella dispar and Rothia mucilaginosa. Contamination profiles varied substantially between kits, with one bacterial species detected in negative extraction controls generated with kit QM and six with kit NM. CONCLUSIONS: Kit QM is the most suitable of the kits tested for the extraction of bacterial DNA from human milk. SIGNIFICANCE AND IMPACT OF THE STUDY: Choice of extraction method impacts the efficiency of bacterial DNA extraction from human milk and the resultant bacterial community profiles generated from these samples.

Impact of expression mode and timing of sample collection, relative to milk ejection, on human milk bacterial DNA profiles.

AIM: To investigate the impact of expression mode: electric breast pump or hand expression, and timing of sample collection: pre- and post-milk ejection on human milk (HM) bacterial DNA profiles. METHODS AND RESULTS: Three HM samples from the same breast were collected from 30 breastfeeding mothers: a pre-milk ejection pump-expressed sample (pre-pump), a post-milk ejection pump-expressed sample (post-pump) and a post-milk ejection hand-expressed sample (post-hand). Full-length 16S rRNA gene sequencing was used to assess milk bacterial DNA profiles. Bacterial profiles did not differ significantly based on mode of expression nor timing of sample collection. No significant differences were detected in the relative abundance of any OTUs based on expression condition (pre-pump/ post-pump and post-pump/post-hand) with univariate linear mixed-effects regression analyses (all P-values > 0·01; α = 0·01). Similarly, no difference in richness was observed between sample types (number of observed OTUs: post-pump/post-hand P = 0·13; pre-pump/post-pump P = 0. 45). CONCLUSION: Bacterial DNA profiles of HM did not differ according to either expression method or timing of sample collection. SIGNIFICANCE AND IMPACT OF THE STUDY: Hand or pump expression can be utilized to collect samples for microbiome studies. This has implications for the design of future HM microbiome studies.

Trophic ecology of sympatric batoid species (Chondrichthyes: Batoidea) assessed by multiple biogeochemical tracers (δ13C, δ15N and total Hg).

Aquatic pollution is known to reduce biodiversity and disrupt wildlife populations. Mercury (Hg) pollution is pervasive worldwide, contributing to the degradation of ecosystems, and causing deleterious effects to exposed organisms and populations. Batoids have a life history linked to the benthic substrate of coastal areas and occupy upper trophic levels. These combined with large bodies, long lifespan, and slow growth rates contributes to increased uptake and accumulation of Hg. However, mechanisms governing these associations are not well understood. Using multiple biogeochemical tracers (δ13C, δ15N and total Hg), we describe trophic interactions of three sympatric batoid species inhabiting an urbanized estuary and identify diet sources that contribute to Hg accumulation and trophic position among these mesopredators. We also use the Bat-ray (Myliobatis californica) as a model species, to compare diet composition, trophic position, and isotopic niche between two populations in two Californian bays. Trophic plasticity in M. californica was characterized by isotopic niche, diet proportions, and trophic position estimates using Bayesian statistics. We found diet and local contamination background strongly associated with Hg accumulation, and Hg levels that exceed EPA water quality criterion (<0.3 µg.g-1 w.w.) in all studied species.

[Clinical features and prognosis analysis of myelin oligodendrocyte glycoprotein antibody-positive optic neuritis].

Objective: To investigate the clinical characteristics and prognosis of myelin oligodendrocyte glycoprotein (MOG) antibody-positive optic neuritis (ON). Methods: The data of 39 patients with MOG antibody-positive ON in the Department of Neurology of Beijing Tongren Hospital, Capital Medical University from January 1, 2017 to October 31, 2019 were retrospectively collected. There were 25 males and 14 females, aged from 15 to 80 (40±16) years. According to the recurrence, the patients were divided into two groups: the recurrence group (n=12) and the non-recurrence group (n=27). The clinical manifestations, relapse-related factors, magnetic resonance imaging (MRI) manifestations, treatment and prognosis of the two groups were analyzed. Results: A total of 63 eyes were involved, including 30 cases of optic perineuritis (OPN), accounting for 47.6% (30/63). The number of attacks ranged from 1 to 9, among which 12 patients had more than 2 attacks. There were 37 eyes [58.7% (37/63)] with severe visual loss (SVL) at the time of onset, and 7 eyes [11.1% (7/63)] with SVL at the final follow-up. Forty-eight eyes [76.2% (48/63)] had optic disc edema. Forty seven eyes [74.6% (47/63)] showed long-segment disease on optic nerve MRI. One case was complicated with aseptic meningitis and encephalitis. The recurrence group was younger than the non-recurrence group [(28.5±9.8) years vs (43.3±16.4) years, P=0.001]. There were no statistically significant differences between the two groups in gender, bilateral onset, initial visual acuity, final visual acuity, optic disc edema, head and spinal cord lesions, and immunosuppressant (all P>0.05). All patients were treated with methylprednisolone (MP) pulse therapy during the acute attack, and 16 of them were additively treated with immunosuppressive agents; the pain was alleviated or relieved significantly after the application of glucocorticoids. Conclusions: MOG antibody-positive ON often occurred in both eyes at the same time, often manifesting as OPN, often accompanied by optic disc edema, and SVL at the beginning of the disease, but most of the visual recovery was good, might be associated with meningitis and encephalitis. MRI of the optic nerve showed that the lesions often manifested as long-segment lesions. Glucocorticoids could alleviate pain and promote the recovery of visual function.

[Five cases of optic neuropathy associated with varicella zoster virus infection].

Objective: To investigate the clinical characteristics, treatment and prognosis of optic neuropathy associated with varicella zoster virus (VZV). Methods: Five cases of optic neuropathy associated with VZV infection from Department of Neurology between January 1, 2014 and March 31, 2019 were retrospectively collected. The clinical manifestations, treatment and prognosis were analyzed. Results: There were 7 eyes involved in 5 cases, 3 cases (3/5) involved only one eye, and 2 cases (2/5) involved both optic nerves. During the follow-up time, no recurrence was found. Severe visual impairment occurred in 4 eyes (4/7) and non-severe visual impairment in 3 eyes (3/7). Visual acuity improved significantly in 1 eye (1/7), turned better in 2 eyes (2/7), and remained unchanged in 4 eyes (4/7). In acute phase, abnormal signals of optic nerve and/or sheath were observed on MR images. Case 3 received antiviral and hormone therapy on the second day after the onset of the disease, and the visual acuity recovered well; the other 4 cases had poor prognosis. Conclusions: Head and face VZV infection can cause serious optic neuropathy, leading to severe visual dysfunction, and poor prognosis, but recurrence is rare. Early intravenous administration of antiviral drugs (acyclovir is the best) and hormones are recommended for VZV infection in this area. It is best to use drugs within 72 hours in order to avoid and reduce secondary optic neuropathy as far as possible.

[Clinical analysis of 36 cases of idiopathic intracranial hypertension complicated with iron deficiency anemia].

Objective: To investigate the clinical features, imaging findings and prognosis of idiopathic intracranial hypertension (IIH) patients complicated with iron deficiency anemia (IDA). Methods: A total of 307 cases of IIH patients hospitalized in Beijing Tongren Hospital were retrospectively screened between January 1, 2011 and February 28, 2018. There were 49 anemia cases (15.96%) and 45 IDA cases (14.66%), respectively. Finally, 36 IDA patients were enrolled. The clinical characteristics, imaging findings, treatment and prognosis of these patients were analyzed. Results: IIH combined with IDA was more common in women of childbearing age (34/36). There were 30 obese and overweight cases (83.33%), with multiple subacute or chronic course of disease. The visual symptoms in the early IIH patients were first diagnosed in the Department of Ophthalmology. The first symptom was headache with/without visual symptoms (27 cases (75%)). Head MRI detected empty sella or partial empty sella, and 2 cases of venous sinus thrombosis were found in DSA examination. Of the 34 female patients, 24 had simple menometrorrhagia or menstrual disorder. All patients were given methyl acetate to reduce the intracranial pressure and iron therapy. Five patients received low molecular weight heparin-warfarin sequential treatment, 5 cases underwent gynecologic surgery and 2 male cases received hemorrhoid operation. There were 7 cases underwent lumbar cisterna-peritoneal shunt for visual impairment. During the follow-up, intracranial pressure decreased and visual function of patients improved significantly. Conclusions: IIH is frequently found in obese or overweight women at childbearing age and IDA may be an important cause of IIH. IIH can cause serious irreversible visual impairment. Therefore, early identification and active treatment should be performed. Correction of anemia can significantly improve the clinical symptoms of IIH. Operation should be employed for IIH patients with poor visual function or rapid progress, in order to reduce intracranial pressure and improve prognosis as soon as possible.

[The clinical analysis of optic neuropathy relative to Behcet's disease with clinical manifestation of anterior ischemic optic neuropathy].

Objective: To summarize the clinical manifestation, treatment and prognosis of anterior ischemic optic neuropathy(AION) which was the manifestation of optic neuropathy related with Behcet's disease (BD). Methods: Retrospective series of case studies. The clinical data of 6 cases (9 eyes) of AION associated with BD who were hospitalized at the neurology ward of Beijing Tongren Hospital from February to June in 2016 were collected, the clinical characteristics of these patients were summarized, visual acuity were compared by using Wingerchuk visual grade before and after treatment. Results: Among the 6 patients with AION associated with BD, there were 4 males and 2 female, aged 38-60 years. All patients were acute onset, 3 cases had the onset of one eye, 2 cases with the onset of both eyes and 1 case with successively onset of both eyes. Optic nerve was damaged in 6 cases (9 eyes), only 1 case felt pain of eyes, the best corrected visual acuity of 4 eyes were less than 0.1, optic disk edema and linear bleeding around optic disk were oberved in all patients, the lower half visual field defect was the most common damage type (5 eyes), P100 latency of visual evoked potential prolonged in all patients, optic nerve MRI showed abnormal signal of optic nerve involvement in 2 patients. All patients were treated with corticosteroids and followed for 3 months, there was significant improvement in 1 eye of which the vision improved above 3 grade, and improvement in 6 eyes of which vision improved for 1-2 grade, while there has been no change in 2 eyes. Conclusions: BD may be the etiology of AION. Visual impairment of this kind of patients is relatively serious, visual function is expected to improve with early treatment. (Chin J Ophthalmol, 2019, 55:203-207).

[Clinical features of chronic relapsing inflammatory optic neuropathy].

Objective: To explore the clinical characteristics and prognosis of chronic relapsing inflammatory optic neuropathy (CRION). Methods: A retrospective analysis was conducted. Clinical features, disease course, prognosis and magnetic resonance imaging (MRI) of patients with CRION who were admitted to Department of Neurology between 2014 and 2016 were reviewed and analyzed. Results: Totally, there were 27 patients (10 males and 17 females), with an age range of 17-59 years. The disease duration was between 40 days and 8 years. There were 2 to 9 CRION episodes. The mean frequency of CRION episodes was 3.30±1.56. The outcome of visual acuity showed that the more episodes frequency was, the worse outcome became. There was 25 abnormal optic nerve signals in MRI. And in 22 cases, the abnormal signals were in intraorbital segment or inner pipe section. The antinuclear antibodies (ANA) titers were elevated in 5 patients. Five cases relapsed during reduction or withdrawal of steroids, but steroids was not added in time. The final outcome of these 5 patients was poor. Conclusions: CRION was more common in female than male patients. Most patients were companied by pain, and the lesions were more common in the intraorbital segment of optic nerve. The more episode frequency was, the worse prognosis became. If a relapse happened, steroids or other immunosuppressive agents should be used.

Effects of maternal dietary egg intake during early lactation on human milk ovalbumin concentration: a randomized controlled trial.

BACKGROUND: There is limited understanding of how maternal diet affects breastmilk food allergen concentrations, and whether exposure to allergens through this route influences the development of infant oral tolerance or sensitization. OBJECTIVE: To investigate how maternal dietary egg ingestion during early lactation influences egg protein (ovalbumin) levels detected in human breastmilk. METHODS: In a randomized controlled trial, women were allocated to a dietary group for the first six weeks of lactation: high-egg diet (> 4 eggs per week), low-egg diet (one-three eggs per week) or an egg-free diet. Breastmilk samples were collected at 2, 4 and 6 weeks of lactation for the measurement of ovalbumin. The permeability of the mammary epithelium was assessed by measuring the breastmilk sodium : potassium ratio. Egg-specific IgE and IgG4 were measured in infant plasma at 6 weeks, and prior to the introduction of egg in solids at 16 weeks. RESULTS: Average maternal egg ingestion was associated with breastmilk ovalbumin concentration. Specifically, for each additional egg ingested per week, there was an average 25% increase in ovalbumin concentration (95% CI: 5-48%, P = 0.01). Breastmilk ovalbumin concentrations were significantly higher in the 'high-egg' group (> 4 eggs per week) compared with the 'egg-free' group (P = 0.04). However, one-third of women had no breastmilk ovalbumin detected. No detectable associations were found between mammary epithelium permeability and breastmilk ovalbumin concentrations. Infant plasma egg-specific IgG4 levels were also positively associated with maternal egg ingestion, with an average 22% (95% CI: 3-45%) increase in infant egg-specific IgG4 levels per additional egg consumed per week (P = 0.02). CONCLUSIONS AND CLINICAL RELEVANCE: Increased maternal egg ingestion is associated with increased breastmilk ovalbumin, and markers of immune tolerance in infants. These results highlight the potential for maternal diet to benefit infant oral tolerance development during lactation.

How can the R.E.N.A.L. nephrometry scoring system aid management of a solid renal mass?

OBJECTIVES. To investigate use of the R.E.N.A.L. nephrometry score in relation to the choice of treatment and postoperative complications for renal masses. DESIGN. Case series. SETTING. A tertiary referral hospital in Hong Kong. PATIENTS. Data of patients undergoing nephrectomy were collected retrospectively from a clinical database and analysed. A R.E.N.A.L. nephrometry score was allocated to each renal tumour by a blinded qualified radiologist, utilising computerised imaging systems. Patient demographics, choice of surgery (radical vs partial), and approaches (open vs minimally invasive) were analysed with respect to their R.E.N.A.L. score. RESULTS. In all, 74 patients were included during the study period, of which 38 underwent partial nephrectomy and 36 underwent radical nephrectomy. No differences between the groups were found with respect to patient demographics. There were significant differences between the partial and radical nephrectomy groups in terms of their mean nephrometry score (6.9 vs 9.3, P<0.001). The mean nephrometry sum was also significantly different in the open approach versus the minimally invasive approach in patients having partial nephrectomy (7.8 vs 6.0, P=0.001). There was no difference in the postoperative 90-day morbidity and mortality in the partial nephrectomy and radical nephrectomy groups. CONCLUSIONS. The R.E.N.A.L. nephrometry score of a renal mass correlated significantly with our choice of surgery (partial vs radical) and our approach to surgery (open vs minimally invasive surgery), particularly in the partial nephrectomy group. It does not, however, correlate with postoperative complications. The nephrometry score provides a useful tool for objectively describing renal mass characteristics and enhancing better communication for the operative planning directed at renal masses.

Bioimpedance spectroscopy in the infant: effect of milk intake and extracellular fluid reservoirs on resistance measurements in term breastfed infants.

BACKGROUND/OBJECTIVES: Bioimpedance spectroscopy is an accurate non-invasive method for measuring body composition in adults, but in infants it requires further testing and validation. Of the few studies of bioimpedance conducted in infants, none have comprehensively investigated the effect of milk intake volume. This study assessed the effect of the milk intake, feed duration and the volume of the infant's stomach and bladder on the resistance values pre-/post-feed to establish the feasibility of using these values interchangeably during data collection. SUBJECTS/METHODS: Forty-eight breastfeeding infants were measured at 2, 5, 9 and/or 12 months (n=62 sessions) within 1-2 min before the start and after the end of breastfeed. Median (IQR) time between measurements was 24 (20.0-30.0) min. Resistance measurements at 0 and 50 kHz, and infinite frequency (R0, R50 and Rinf) and resistance of intracellular water (Ricw) were analysed with customised infant settings. Milk intake was measured by test weights. Free-water volumes and free-water change were determined from stomach and bladder volumes calculated from ultrasound images. RESULTS: Small pre-to-post-feed changes (median (IQR): R0 -3.7 (-14.8, 14.3); R50 0.3 (-10.4, 15.0); Rinf 2.8 (-13.3, 35.5); Ricw 20.8 (-98.1, 290.9)) were not significantly different from zero (R0: P=0.92; R50: P=0.48; Rinf: P=0.32; Ricw: P=0.097). No significant effect of milk intake or free-water change was detected. CONCLUSIONS: The lack of consistent change in resistance across a breastfeed provides flexibility in the timing of measurements of infants in the research setting, such that typically pre- and post-feed measures of resistance can be used interchangeably.

The high-frequency component of heart rate variability during extended wakefulness is closely associated with the depth of the ensuing sleep in C57BL6 mice.

This study aimed to test the hypothesis that, during extended wakefulness, parasympathetic activity is associated with the depth of the subsequent recovery sleep in mice. Fourteen male C57BL/6 mice were implanted with electrodes for sleep recording. Continuous spectral analysis was performed on the electroencephalogram (EEG) to obtain theta power (6-9Hz) and delta power (0-4Hz), as well as the R-R interval signals in order to quantify the high-frequency power (HF) and normalized low-frequency power (LF%) that are used to assess parasympathetic and sympathetic activity, respectively. All animals underwent a sleep deprivation experiment and a control experiment (6-h intervention and 1-h recovery period) on two separate days. During sleep deprivation, HF and theta power during wakefulness were significantly higher than during the control wakefulness after the second hour and first hour, respectively. During recovery non-rapid eye movement sleep, there was a rebound in sleep time and delta power as well as an elevation in HF relative to control post-intervention sleep. Both the rise in HF and theta power during extended wakefulness were found to be positively correlated with the delta power rebound. Furthermore, the HF change during extended wakefulness was also correlated with the amount of sleep loss and the enhancement of waking theta power. Our finding suggests that waking parasympathetic activity intimately reflects the cumulative sleep pressure, suggesting a potential role to be an autonomic marker for sleep propensity.

Dopamine- and L-beta-3,4-dihydroxyphenylalanine hydrochloride (L-Dopa)-induced cytotoxicity towards catecholaminergic neuroblastoma SH-SY5Y cells. Effects of oxidative stress and antioxidative factors.

Enhanced oxidative stress has been suggested to be involved in the degeneration of nigrostriatal dopaminergic neurons in Parkinson's disease. The high turnover rate of dopamine and/or unsequestered dopamine may cause an increase of formation of hydrogen peroxide via either oxidative deamination of dopamine by monoamine oxidase or autoxidation. Hydrogen peroxide would be converted to more toxic hydroxyl free radicals. L-beta-3,4-Dihydroxyphenylalanine hydrochloride (L-DOPA), the most useful drug in the symptomatic treatment of Parkinson's disease, has been considered to possess deteriorating degenerative side-effects. The catecholaminergic neuroblastoma SH-SY5Y cells were chosen to investigate the cytotoxic effect of dopamine and L-DOPA. Both dopamine and L-DOPA were found to be cytotoxic towards SH-SY5Y cells. Such toxic effects were accompanied by an increase of oxidative stress in the cell cultures and could be reversed effectively by catalase and to a lesser extent by superoxide dismutase. The non-enzymatic antioxidants L-ascorbic acid, glutathione, N-acetyl-L-cysteine, but not (+)-alpha-tocopherol, also completely protected SH-SY5Y cells against the cytotoxic effects induced by dopamine and L-DOPA. Antioxidative factors, namely free radical scavengers (including N-tert-butyl-alpha-phenylnitrone, salicylic acid, and D-mannitol) and a strong iron chelator, deferoxamine, however, did not protect the SH-SY5Y cells against dopamine and L-DOPA. The generation of reactive oxygen species and the resulting enhanced oxidative stress was clearly involved in the dopamine- and L-DOPA-induced cytotoxic effects. Hydrogen peroxide played the most important role related to cytotoxicity of dopamine and L-DOPA.

Neurochemical, neuroprotective and neurorescue effects of aliphatic N-methylpropargylamines; new MAO-B inhibitors without amphetamine-like properties.

A series of aliphatic N-methylpropargylamine MAO-B inhibitors have been synthesized and their structural and functional relationships have been investigated. 2-Hexyl-N-methylpropargylamine (2-HxMP), for example, has been found to be a highly potent, irreversible, selective, MAO-B inhibitor both in vitro and in vivo. The R-(-)-enantiomers are much more active than the S-(+)-enantiomers at inhibiting MAO-B activity. Some of these compounds protect mouse nigrostriatal dopamine neurons against the neurotoxin MPTP and the mouse hippocampal noradrenergic system against the neurotoxin N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4). They rescue hippocampal neurons after damage induced by ischemia and kainic acid treatment, as well as motoneurons in young mice following facial nerve axotomy. Such rescue effects are, interestingly, unrelated to inhibition of MAO-B activity. Some of the aliphatic propargylamines enhance the survival of neuroblastoma cells co-cultured with astrocytes following serum depletion. They stimulate the expression of AADC mRNA and inhibit GFAP mRNA expression. They do not possess amphetamine-like properties and exhibit no effect on noradrenaline or dopamine uptake nor do they increase hypertensive effects in the tyramine pressor test. Unlike R(-)-deprenyl, 2-HxMP does not potentiate dopamine toxicity in vitro. These new MAO-B inhibitors may possess significant chemotherapeutic implications for certain psychiatric and neurodegenerative disorders.

Aliphatic N-methylpropargylamines as potential neurorescue agents.

Several clinical investigations have indicated that R-deprenyl, a typical monoamine oxidas B inhibitor, delays the progression of Parkinson's and Alzheimer's disease. A number of aliphatic N-methylpropargylamines, such as R-2-hexyl-N-methylpropargylamines (R-2HxMP), have been found to be highly potent, irreversible, selective, MAO-B inhibitors both in vitro and in vivo. These aliphatic propargylamines do not affect noradrenaline of dopamine uptake and are chemically without an amphetamine moiety and therefore do not exhibit any amphetamine-like effects. They are capable of protecting mouse striatal dopamine neurons against MPTP-induced toxicity in the caudate, against MK-801-induced apoptosis in the retrosplenial cortex and against DSP-4-induced depletion of naradrenergic axons. They rescue hippocampal neurons in rodents following kainate-induced neuronal damage. They block the expression of heat shock protein (HSP70) and delayed c-Fos expression in hippocampal CA1 region as elicited by kainate. Confocal microscopy also revealed prevention of neuronal damage in hippocampal slices under hypoxia-hypoglycemia conditions. Aliphatic N-methylpropargylamines may be useful in the treatment of neurodegenerative disorders. The mechanism and site of action of the neurorescue effect of these propargylamines, however, remains to be established.

Effects of phenelzine and imipramine on the steady-state levels of mRNAs that encode glutamic acid decarboxylase (GAD67 and GAD65), the GABA transporter GAT-1 and GABA transaminase in rat cortex.

There is an increasing body of evidence suggesting that GABA plays an important role in the therapeutic effects of antidepressant/antipanic drugs. Phenelzine and imipramine are efficacious in the treatment of depression and panic disorder and phenelzine has been reported to elevate GABA levels while imipramine enhances GABA release in rat brains. In the present study, using a multiprobe quantitative solution hybridization assay, we measured the steady-state levels of mRNAs that encode glutamic acid decarboxylase (GAD67 and GAD65), the GABA transporter GAT-1 and GABA transaminase (GABA-T) in rat cortex after treatment with constant infusion (via osmotic minipumps) of phenelzine or imipramine for a short-term (3 days) or long-term (21 days) period. We found that none of the treatments gave rise to significant changes in the steady-state levels of mRNAs encoding GAD67, GAD65 or GABA-T at any time point. The steady-state levels of GAT-1 mRNA were increased significantly (23%) after long-term, but not by short-term, treatment with phenelzine. Imipramine treatment, short- or long-term, did not alter the steady-state levels of GAT-1 mRNA. These results suggest that the GABA enhancing effects of phenelzine or imipramine in rat cortex do not affect the steady-state levels of mRNAs that encode GAD67, GAD65 and GABA-T. Further, the previously observed increases in GABA levels or GABA release induced by these drugs are probably not a consequence of changes in the expression of these genes.

Is brain superoxide dismutase activity increased following chronic treatment with 1-deprenyl?

L-deprenyl, a specific MAO-B inhibitor, has been proposed to possess a neuroprotective effect. The mechanism of such an effect is unclear. L-Deprenyl has been found to increase rat striatal superoxide dismutase (SOD) activity, which inactivates singlet oxygen. It would be very interesting to know how such activation occurs and whether or not other MAO inhibitors also have such an effect. We have analyzed rat striatal SOD activity using a very sensitive nitrite method and an immunological procedure. The effect of different doses and time of treatment with 1-deprenyl and M-2-PP (2-pentyl-N-methyl-propargylamine), a new highly potent, selective and non-amphetamine-like MAO-B inhibitor, on the rat brain has been investigated. We were unable to detect any increase of SOD activity in the rat striata and cerebral cortex nor any increase in the concentration of immunoreactive SOD antibody in the cortex following chronic treatment with 1-deprenyl and M-2-PP. It remains to be substantiated as to whether or not 1-deprenyl can enhance SOD levels.

Chronic L-deprenyl or L-amphetamine: equal cognitive enhancement, unequal MAO inhibition.

The effect of chronic (4 month), subcutaneous injections of saline, L-deprenyl (0.25 mg/kg), or L-amphetamine (0.25 mg/kg) on the acquisition of a learned spatial habit in a modified Morris Water Maze was investigated in middle aged rats. Injections, given three times weekly starting at 6 months of age, were continued during behavioral testing, which occurred at 10 months of age. The cognitive performance of the middle aged rats was compared to that of 2-month-old control rats. Twenty-four hours after the last behavioral test, the rats were sacrificed and their brains were removed, dissected, and frozen in liquid nitrogen. The activities of MAO-A and MAO-B in the lateral cortex were determined. Results indicate that rats in the L-deprenyl group, the L-amphetamine group, and the young control group all learned the water maze task equally rapidly and significantly faster than rats in the saline group. MAO-A did not differ among the saline, amphetamine, and young control rats, but MAO-B was significantly higher in the middle aged saline and L-amphetamine rats than in the young controls. Both MAO-A and MAO-B activities were significantly lower in the L-deprenyl group than in the other three groups. This indicates that low-dose L-deprenyl can also inhibit MAO-A following chronic SC administration. Moreover, the improved cognitive performance produced by L-deprenyl may not be due to its ability to inhibit MAO-B, but rather to some other effect such as the activation of growth factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Vascular contractile properties in hypertension. I. A study of testing methods.

Abnormal contractile responses of blood vessels are observed widely in several hypertension models and are assumed to play a role in the etiology of essential hypertension. Inconsistent reports also exist due to different animals, preparations, and experimental techniques employed. In this investigation, we compared vascular response of normotensive Wistar-Kyoto rat (WKY) with that of spontaneously hypertensive rat (SHR) employing two experimental methods. Thoracic aorta obtained from age-matched animals were contracted by norepinephrine (NE) with either--single-dose method or cumulative-dose method. Differences in both reactivity (maximal tension) and sensitivity (ED50) to NE were observed. Although no significant differences were found between WKY and SHR with either method, the choice of the method employed could affect the outcome. For aorta from WKY, the reactivity to NE was similar for both methods; however, for aorta from SHR, the reactivity obtained by cumulative-dose method was significantly higher. Furthermore, the cumulative-dose method yielded higher sensitivity in both WKY and SHR when compared with that obtained by single-dose method. Taken together, the cumulative-dose method appeared to be a more sensitive method to determine contractile response. Nevertheless, no significant difference in either reactivity or sensitivity to NE in aorta was detected between WKY and SHR when cumulative-dose method was employed. These data indicate that aorta do not exhibit abnormal response to NE in SHR, consistent with earlier findings that not all tissue preparations behave similarly.