Pesticide retention by a programmable automatic water/suspended-sediment sampler.
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Acetamides↗
Biomedical subjects
S Smith
Publications and source records attributed to S Smith.
Combined intrauterine triplet and ectopic pregnancy following pronuclear embryo transfer in a patient with elevated serum progesterone during ovulation induction.
We present a case of heterotopic pregnancy occurring after ET of pronuclear-stage embryos. This case demonstrates that pronuclear embryos have a good implantation potential and suggests that the potentially adverse effect of high follicular-phase serum progesterone levels on endometrial development might be offset by early ET of pronuclear embryos. This, however, is speculative and deserving of formal scientific evaluation. Finally, we are reminded that heterotopic pregnancy complicates 1 to 3% of IVF-ET pregnancies and that, even with a high index of suspicion, most heterotopic pregnancies are diagnosed after rupture. All assisted reproductive programs should be reminded frequently that ectopic and heterotopic pregnancies do occur and can lead to serious consequences if left undetected.
Adult↗
Genetic characterization of a familial non-specific dementia originating in Jutland, Denmark.
Dementias with non-specific pathological changes are a relatively common but under diagnosed form of presenile dementia. A high proportion of reported cases are familial. We report on molecular genetic findings in the largest known pedigree with this syndrome. We have excluded the mutations known to cause familial prion disease, APP-linked familial Alzheimer's disease and candidate regions for Huntington's disease, other forms of Alzheimer's disease and motor neuron disease. We have demonstrated that familial non-specific dementia is a novel genetic dementia.
Aged↗
The effect of BAY u 3405, a thromboxane receptor antagonist, on prostaglandin D2-induced nasal blockage.
BACKGROUND: Nasal lavage and challenge studies in allergic rhinitis implicate prostaglandin (PG) D2 in the genesis of nasal blockage. PG D2 is known to act via at least two receptors, the thromboxane prostanoid receptor and the PG D2 prostanoid (DP) receptor; the lower airway effects are mediated chiefly by the TP receptor. The receptor involved in the genesis of PG D2-induced nasal blockage is unknown. BAY u 3405 is a potent selective competitive TP receptor antagonist, which inhibits the lower airway response to PG D2, and shifts the dose-response curve to the right by up to 16-fold. METHODS: The efficacy of a single oral dose of 20 mg of BAY u 3405 was examined in comparison with PG D2 nasal insufflation in a randomized, double-blind, placebo-controlled crossover study, with objective measurement of nasal resistance by active posterior rhinomanometry. RESULTS: BAY u 3405 afforded no protection against PG D2-induced nasal blockage. CONCLUSIONS: This suggests that PG D2-induced nasal blockage may be mediated by the DP receptor rather than the TP receptor and that TP receptor antagonists are unlikely to be of benefit in the treatment of allergic rhinitis. In vivo investigation with specific potent DP receptor antagonists is awaited.
Adult↗
Hydrogels as an interface between bone and an implant.
The use of fully hydrated hydrogels in the body has been well established. The forces a hydrogel generates on swelling when it is placed in a constrained space were investigated with a view to providing a mechanism for fixing a prosthesis in the intramedullary cavity. A cross-linked poly(2-hydroxyethyl methacrylate) [p(HEMA)] hydrogel was investigated as a potential material. In vitro mechanical tests were carried out to determine the stresses generated in the p(HEMA) when it was placed in water and not allowed to swell. Pull out loads of up to 375 N indicated that the system could be used successfully in vivo. Consequently, the material was placed intraosseously at two sites in a rabbit animal model, in the mid-shaft (diaphysis) and the lower end (metaphysis) of the femur. Histological examination showed there was no adverse bone response; bone was growing from the endosteal surface up to and into the hydrogel in the diaphyseal implants and surrounded the hydrogel in the metaphysis. As a result of the shape and size variations in the rabbit femur, in vivo mechanical tests were found to give lower values than those obtained in vitro.
Animals↗
Substance abuse vulnerability and D2 receptor genes.
Dopamine systems are key to the actions of several substances. Inter-individual differences in genes encoding proteins involved in dopaminergic neurotransmission could plausibly explain some of the genetic bases for inter-individual differences in vulnerability to substance abuse. The restriction fragment length polymorphism (RFLP) markers TaqIA1 and B1 at the dopamine D2 receptor (DRD2) gene locus in Caucasians are associated with substance abuse behaviors. In most, but not all, studies of alcoholics and polysubstance abusers, these TaqIA1 and B1 gene markers are present more often in substance abusers than in control individuals. No study has identified substance abusers or controls by sampling randomly from the general population; allelic association findings could thus conceivably be confounded by RFLP differences based on ethnicity or other factors. However, meta-analyses of the data from controlled studies available to date are consistent with the proposal that DRD2 gene variants contribute to inter-individual differences in vulnerability to alcoholism and polysubstance abuse.
Animals↗
Creatinine assay by the fuller's earth procedure or by enzymatic determination is adequate for urine but not plasma of mice.
1. Mouse plasma creatinine measured by fuller's earth (15.1 +/- 0.5(41) microM, mean +/- SE) exceeded the same pools read by HPLC [7.5 +/- 0.2(41); P < 0.001]. 2. For mouse urine, the fuller's earth method (3.26 +/- 0.21 mM) slightly exceeded the HPLC method (2.65 +/- 0.18; P < 0.001) with good correlation (r = 0.915, P < 0.001). 3. An enzymatic method (creatinine PAP, Boehringer-Mannheim Diagnostics) for plasma creatinine (5.2 +/- 0.3 microM) was equivalent to HPLC (6.1 +/- 0.1, NS) but with poor correlation (r = 0.23, NS). 4. Creatinine in the urine agreed closely between HPLC (2.84 +/- 0.12 mM) and the enzymatic procedure (2.95 +/- 0.17, NS) with good correlation (r = 0.845, P < 0.001).
Aluminum Compounds↗
ERP abnormalities during semantic processing in schizophrenia.
To examine the neurophysiological and cognitive characteristics of thought disturbance in schizophrenic patients, we examined the amplitude, latency, and topography of a specific event-related brain potential (ERP), the N400, which is elicited by semantically incongruent words and phrases. Twelve chronic schizophrenic patients and twelve age-matched control subjects read sentences presented visually that had either semantically correct (e.g., 'People pray in their local church') or incorrect endings (e.g., 'Every Sunday morning people pray in their local nest'). Relative to normal controls, schizophrenic patients had significantly reduced N400 amplitude and increased latency to semantically anomalous endings. Additionally, a late positive component which follows the N400 was significantly reduced in amplitude in schizophrenic patients. However, patients and controls did not differ significantly in terms of the topographical distribution of either the N400 or its late positive potential, examined at 28 electrode sites. Thus, N400 topography in schizophrenic patients was not accompanied by the asymmetry which frequently characterizes the well known auditory P300 disturbance in schizophrenic patients. We concluded that these findings may reflect a profound disturbance in attentional processes in chronic schizophrenia.
Adult↗
The use of a liquid-phase controlled rate freezing system for the successful cryopreservation of mouse pre-embryos.
OBJECTIVES: To investigate the ability of a liquid-phase, controlled-rate freezing machine to generate reproducible freezing gradients with a constant rate of change; temperature fluctuations and heat dissipation during seeding; to assess the viability of mouse pre-embryos exposed to the silicone liquid cooling phase and the rates of survival and viability of mouse pre-embryos cryopreserved using this system. DESIGN: Freezing gradients were generated from the bath or a sample and compared for reproducibility and slope. Temperature fluctuations and gradients around the freezing chamber and the temperature rises and dissipation during seeding were measured. The toxicity of the silicone polymer freezing-phase was tested with mouse pronuclear pre-embryos. Different developmental stages of mouse pre-embryos were frozen and thawed and survival recorded in vitro and in vivo. SETTING: Research Laboratories, Sinai Hospital of Baltimore, Baltimore, Maryland. MAIN OUTCOME MEASURES: The reproducibility of freezing gradients; temperature fluctuations during seeding; and the in vitro and in vivo viability of mouse pre-embryos exposed to the silicone polymer or frozen and thawed. RESULTS: The freezing gradients generated were constant and reproducible with a constant rate of change; no temperature differences were recorded around the freezing chamber; temperature changes at seeding are minimal and rapidly dispersed. The silicone polymer was nontoxic to mouse pre-embryos and mouse pre-embryos frozen with the system and subsequently thawed are viable both in vitro and in vivo. CONCLUSIONS: This liquid-phase cryopreservation system is an attractive option for assisted reproductive technologies laboratories because liquid nitrogen is not required for operation, it is reliable, there are small temperature fluctuations during seeding, and it can be kept constantly running.
Animals↗
The relevance and use of mouse embryo bioassays for quality control in an assisted reproductive technology program.
OBJECTIVE: To define both the limits of a mouse embryo bioassay for quality control in an assisted reproductive technology (ART) program and the areas where it can be effectively used. DESIGN: Embryos at the pronuclear and two-cell stage from three different strains of mice were used to assess the effectiveness of this assay for media quality control using five different media routinely used in ART. Pronuclear and two-cell embryos from CD-1 mice were used to test the ability of a mouse embryo bioassay to control for water quality, contaminants in the culture system, and fluctuations in the environmental conditions using a medium, culture system, and scoring technique that were optimized for this strain. RESULTS: The mouse embryo bioassay is not effective in differentiating media appropriate for supporting human embryo development since the development of mouse embryos in vitro is strain, stage, and media related. However, CD-1 embryos were shown to be sensitive to variations in water quality, pH, temperature, incubator conditions, and contaminants in the system when grown in a protein-free medium optimized for their development. Both total blastocyst number and the cell count in the blastocysts were affected. Pronuclear embryos were more sensitive to perturbations in the culture system than two-cell embryos. CONCLUSIONS: A mouse embryo bioassay can be effectively used as a means of quality control of water, chemicals, and contact materials and for technique standardization and training in an assisted reproduction program. All the conditions of the test should be defined, pronuclear embryos should be used, and the end point should be fully expanded blastocysts and/or cell numbers in these blastocysts where appropriate.
Animals↗
Neurones in autonomic ganglia of normal horses contain phosphorylated neurofilaments.
Neurofilaments (NF) are composed of three polypeptides of differing molecular size, termed NF-L, NF-M and NF-H. The NF-H and, to a lesser degree, NF-M components are phosphorylated. In the majority of normal neurones, the location of phosphorylated NF is confined to neuronal processes, particularly the axon, and excluded from the perikaryon. Cell bodies of autonomic neurones of the rat do not contain phosphorylated NF. In many disease states, phosphorylated NF accumulate in the neuronal cell body and therefore in most circumstances their presence indicates abnormality. This paper reports that in at least two autonomic ganglia of normal horses (stellate and coeliomesenteric) the vast majority of neuronal perikarya immunostain strongly for phosphorylated NF. Pretreatment with alkaline phosphatase abolishes staining.
Animals↗
The effects of intraarticular administration of hyaluronan in a model of early osteoarthritis in sheep. II. Cartilage composition and proteoglycan metabolism.
A model of early osteoarthritis (OA) induced in ovine joints by medial meniscectomy was used to study the effects of two hyaluronan (HA) preparations (AHA and DHA) on cartilage composition and proteoglycan (PG) metabolism. DHA was an HA preparation with an average molecular weight (MW) of approximately 2.0 x 10(6) d, and AHA had an MW of approximately 8.0 x 10(5) d. Both preparations were administered intraarticularly once a week for 5 weeks starting 16 weeks after meniscectomy, and animals (n = 5) were killed 5 weeks after the last injection. Meniscectomized, saline-injected (n = 5) and nonoperated (n = 5) animals were used for controls. At necropsy, 3-mm-diameter full-depth cartilage plugs were sampled under sterile conditions from specific locations on the medial and lateral femoral condyles, tibial plateaus, patella, and trochlear groove. The cartilage plugs were cultured in Hams-F12 medium supplemented with 10% fetal calf serum for 24 hours, then for a further 48 hours in the presence of H2(35)SO4 to determine the biosynthesis of PGs. The percentage of 35S-PGs and sulfated glycosaminoglycans released into the media was also ascertained. The cartilage adjacent to the plugs was analyzed for collagen and proteoglycan content and differential extractability with guanidine hydrochloride (GuHCl) solutions. The extractability of PGs with 0.4 mol/L GuHCl (nondissociative conditions) was lower from the medial femoral cartilages of the DHA-treated group than from the corresponding saline-treated group. In contrast, the release of 35S-PGs from the tibial cartilages of the DHA-treated animals was higher than in the saline-treated group. The biosynthesis of 35S-PGs, determined in vitro, for cartilage derived from the medial compartment was generally lower than for the lateral regions of the meniscectomized joints. The biosynthetic activity was further reduced in joints injected with the two HA preparations, but DHA reduced 35SO4 incorporation into PGs more than AHA. It was concluded that reduced biosynthesis of 35S-PGs and secretion into media was a consequence of increased loading of joints in the HA-treated animals rather than a direct effect of these preparations on chondrocyte metabolism.
Animals↗
Additional evidence for the cysteine proteinase nature of gingivain the extracellular proteinase of Porphyromonas gingivalis.
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Cysteine Endopeptidases↗
Strategies to recruit plateletpheresis donors from a registry of HLA-typed, unrelated, bone marrow donors.
Rising demand for single-donor platelet components--from random donors, to maintain platelet inventories, or from HLA-compatible donors, to support alloimmune platelet-refractory patients--necessitated increasing the size of a community plateletpheresis donor registry. This study compares two strategies for recruiting whole-blood donors into a plateletpheresis program. The whole-blood donors who were asked to participate in this study had recently joined an unrelated bone marrow donor registry and had been HLA-typed as part of that process. An in-person recruitment strategy, which was time-intensive for the apheresis donor coordinator, served as the standard. A by-mail strategy involved the mailing of recruitment materials to marrow-donor registry participants. Marrow-donor registry participants were approached about apheresis participation after they had indicated an interest in the plateletpheresis program by returning a tear-off section of an informational brochure that was sent to them along with their marrow-donor registry materials. A total of 852 marrow-donor registry participants were randomly assigned to one of two recruitment strategies, and the recruitment rates were the same (46%) for both methods. In addition, levels of apheresis participation and attrition rates of donors recruited by either strategy were comparable. Thus, the simple strategy of mailing information about a plateletpheresis program is a very cost-effective method of recruiting donors.
Blood Donors↗
Detection of celiac axis and superior mesenteric artery occlusive disease with use of abdominal duplex scanning.
PURPOSE: Detection of mesenteric arterial insufficiency is clinically difficult, and diagnosis frequently requires arteriography. Advances in duplex scanning make this an ideal technique to noninvasively screen patients for chronic mesenteric arterial occlusive disease. However, the accuracy of mesenteric duplex scanning compared with arteriography remains unclear. This study will clearly define the accuracy of abdominal duplex scanning for detection of mesenteric arterial insufficiency. METHODS: The mesenteric duplex scans of 38 patients obtained over a 4-year period were reviewed and compared with lateral aortograms to clarify this issue. Optimal peak systolic frequency (PSF) for predicting less than 50% or 50% or greater stenoses of the superior mesenteric artery (SMA) and celiac axis (CA) were determined from receiver-operating characteristic curves. RESULTS: In the SMA a PSF of 4.5 kHz was 96% sensitive (24/25), 92% specific (12/13), and 95% accurate (36/38) at predicting stenoses less than 50% or 50% or greater. For arteries with stenoses 50% to 99%, regression analysis demonstrated excellent linear correlation between percent stenosis and PSF (r = 0.89). In the CA a PSF of 4.0 kHz had a sensitivity of 100% (30/30), a specificity of 88% (7/8), and an accuracy of 97% (37/38). Again, for arteries with stenoses 50% to 99%, an excellent linear correlation existed between PSF and percent stenosis (r = 0.86). All total arterial occlusions (14) were correctly identified. In all, mesenteric arterial duplex scanning was 96% accurate for predicting SMA and CA stenoses/occlusions. CONCLUSIONS: Abdominal duplex scanning is a noninvasive technique that accurately detects total occlusions and objectively quantitates SMA and CA arterial stenoses.
Aorta, Abdominal↗
Follow-up evaluation after renal artery bypass surgery with use of carbon dioxide arteriography and color-flow duplex scanning.
PURPOSE: Postoperative evaluation of renal artery bypass grafts historically has been obtained by contrast renal arteriography before discharge from the hospital. Recent reports have advocated replacing arteriography with abdominal duplex scanning for evaluating and monitoring the integrity of renal artery bypasses. We propose a combination of these two techniques, which provides minimal risk to the patient and renal parenchymal function. PURPOSE: Between July 1, 1990, and Dec. 31, 1991, 17 patients (8 men, 9 women) underwent 24 renal artery bypasses for poorly controlled hypertension or deteriorating renal function. In the immediate postoperative period each patient underwent carbon dioxide (CO2) renal arteriography to detect any technical defects and to define bypass graft anatomy. Subsequently, color-flow duplex scanning of the renal artery bypass grafts were done at 3-month intervals with the postoperative CO2 arteriogram for baseline comparison. CO2 arteriography clearly defined proximal/distal anastomotic anatomy, bypass conduit integrity, and bypass conduit runoff. RESULTS: Procedural morbidity was zero because no hematomas developed and serum creatinine remained stable. Duplex scanning for a mean follow-up of 8.3 months revealed antegrade flow in 23 bypasses with peak systolic velocity of 60 to 100 cm/sec. One bypass graft had a peak systolic velocity greater than 150 cm/sec suggestive of a proximal anastomotic stenosis; however, the patient died before a repeat, verifying CO2 arteriogram could be obtained. Recurrent hypertension developed in one patient with velocities less than 100/cm/sec, and repeat CO2 arteriography revealed no evidence of graft or anastomotic stenosis. CONCLUSION: CO2 arteriography and duplex scanning provide an accurate means of initially evaluating and subsequently monitoring renal artery bypass grafts, with minimal risk of renal or patient morbidity.
Adult↗
The first membrane spanning region of the lamin B receptor is sufficient for sorting to the inner nuclear membrane.
The lamin B receptor (LBR) is a polytopic integral membrane protein localized exclusively in the inner nuclear membrane domain of the nuclear envelope. Its cDNA deduced primary structure consists of a highly charged amino-terminal domain of 205 residues that faces the nucleoplasm followed by a hydrophobic domain with eight potential transmembrane segments. To identify determinants that sort LBR from its site of integration (RER and outer nuclear membrane) to the inner nuclear membrane, we prepared full-length, truncated, and chimeric cDNA constructs of chick LBR, transfected these into mammalian cells and detected the expressed protein by immunofluorescence microscopy using appropriate antibodies. Surprisingly, we found that the determinants for sorting of LBR to the inner nuclear membrane reside in a region comprising its first transmembrane sequence plus flanking residues on either side. The other transmembrane regions as well as the nucleoplasmic domain are not required for sorting. We propose that the first transmembrane segment of LBR interacts specifically with another transmembrane segment and consider several mechanisms by which such specific interaction could result in sorting to the inner nuclear membrane.
Animals↗
MEG and EEG in epilepsy: is there a difference?
Interictal epileptiform activity recorded by scalp EEG, foramen ovale electrodes and MEG is discussed. Gross differences in waveform between the electric and magnetic records are discussed in the light of intracranial depth recordings.
Electroencephalography↗