Conservation of a sex-determining gene.
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Alligators and Crocodiles↗
Biomedical subjects
C A Smith
Publications and source records attributed to C A Smith.
AABP conference delivers relevant-CE.
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Animals↗
Structure of a soluble secreted chemokine inhibitor vCCI (p35) from cowpox virus.
Most poxviruses, including variola, the causative agent of smallpox, express a secreted protein of 35 kDa, vCCI, which binds CC-chemokines with high affinity. This viral protein competes with the host cellular CC-chemokine receptors (CCRs), reducing inflammation and interfering with the host immune response. Such proteins or derivatives may have therapeutic uses as anti-inflammatory agents. We have determined the crystal structure to 1.85-A resolution of vCCI from cowpox virus, the prototype of this poxvirus virulence factor. The molecule is a beta-sandwich of topology not previously described. A patch of conserved residues on the exposed face of a beta-sheet that is strongly negatively charged might have a role in binding of CC-chemokines, which are positively charged.
Amino Acid Sequence↗
Long-term outcome in children after antenatal intervention for obstructive uropathies.
BACKGROUND: Antenatal intervention has been done for fetal obstructive uropathy for over a decade, yet little is known about long-term outcomes. To assess the long-term implications of fetal intervention, we reviewed the outcomes of children who underwent vesicoamniotic shunt placement. METHODS: We reviewed the clinical outcomes of 14 children who underwent vesicoamniotic shunt placement at our institution and who survived beyond 2 years of age. FINDINGS: In 1987-96, 34 patients underwent vesicoamniotic shunt placement. 13 died and 21 survived, of whom 17 are now more than 2 years old. Three survivors were lost to follow-up. Mean age at follow-up was 54.3 months (range 25-114). Final diagnoses included prune belly syndrome (seven cases), posterior urethral valves (four), urethral atresia (one), vesicoureteral reflux (one), and megacystis (one). Height was below the 25th percentile in 12 (86%) with seven (50%) below the 5th percentile. Five (36%) had renal failure and had successful transplantation, three (21%) have renal insufficiency, and six (43%) have normal renal function. Seven (50%) are acceptably continent, five (36%) have not yet begun toilet-training, and two (14%) are incontinent. Three of four children with valves needed bladder augmentation. INTERPRETATION: Antenatal intervention may help those fetuses with the most severe forms of obstructive uropathy, usually associated with a fatal neonatal course. Intervention achieves outcomes similar to less severe cases that are usually diagnosed postnatally.
Catheters, Indwelling↗
Gene expression during gonadogenesis in the chicken embryo.
Genes implicated in vertebrate sex determination and differentiation were studied in embryonic chicken gonads using reverse transcription and the polymerase chain reaction (RT-PCR). Expression profiles were obtained during gonadal sex differentiation for AMH, SOX9, SOX3, the Wilm's Tumour gene, WT1, and the orphan nuclear receptor genes, SF1 and DAX1. Some of these genes showed sexually dimorphic expression profiles during gonadal development, whereas others were expressed at similar levels in both sexes. The gene encoding Anti-Müllerian hormone (AMH) was expressed in both sexes prior to and during sexual differentiation of the gonads, with levels of expression consistently higher in males than in females. SOX9 expression was male-specific, and was up-regulated after the detection of AMH transcripts. SOX3 expression was observed prior to clear SOX9 expression and was up-regulated in both sexes at the onset of gonadal sex differentiation (but declined later in development). The WT1 gene was highly expressed in both sexes, whereas SF1 expression was clearly higher in developing ovaries compared to testes. DAX1 transcripts were observed in both sexes at all stages examined, but expression appeared somewhat higher in developing ovaries. These expression profiles are analysed in terms of current theories of vertebrate sex determination.
Actins↗
Inhibition of inspiratory motor output by high-frequency low-pressure oscillations in the upper airway of sleeping dogs.
1. We utilized a chronically tracheostomized, unanaesthetized dog model to study the reflex effects on inspiratory motor output of low-amplitude, high-frequency pressure oscillations (HFPOs) applied to the isolated upper airway (UA) during stable non-rapid eye movement (NREM) sleep. 2. HFPOs (30 Hz and +/-2 to +/-4 cmH2O) were applied via a piston pump during eupnoea, inspiratory resistive loading and tracheal occlusion. 3. When applied to the patent UA during expiration, and especially during late expiration, HFPOs prolonged expiratory time (TE) and tonically activated the genioglossus muscle EMG. When applied to the patent UA during inspiration, HFPOs caused tonic activation of the genioglossus muscle EMG and inhibition of inspiratory motor output by either: (a) a shortening of inspiratory time (TI), as inspiration was terminated coincident with the onset of HFPOs; or (b) a prolonged TI accompanied by a decreased rate of rise of diaphragm EMG and rate of fall of tracheal pressure. These effects of HFPOs were observed during eupnoea and inspiratory resistive loading, but were maximal during tracheal occlusion where the additional inhibitory effects of lung inflation reflexes were minimized. 4. During eupnoea, topical anaesthesia of the UA abolished the HFPO-induced prolongation of TE, suggesting that the response was mediated primarily by mechanoreceptors close to the mucosal surface; whereas the TE-prolonging effects of a sustained square wave of negative pressure (range, -4.0 to -14.9 cmH2O) sufficient to close the airway were preserved following anaesthesia. 5. These results demonstrate that high-frequency, low-amplitude oscillatory pressure waves in the UA, similar to those found in snoring, produce reflex inhibition of inspiratory motor output. This reflex may help maintain UA patency by decreasing the collapsing pressure generated by the inspiratory pump muscles and transmitted to the UA.
Afferent Pathways↗
International involvement, total milk quality focus of NMC.
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Animals↗
Functional analysis of TRAIL receptors using monoclonal antibodies.
mAbs were generated against the extracellular domain of the four known TNF-related apoptosis-inducing ligand (TRAIL) receptors and tested on a panel of human melanoma cell lines. The specificity of the mAb permitted a precise evaluation of the TRAIL receptors that induce apoptosis (TRAIL-R1 and -R2) compared with the TRAIL receptors that potentially regulate TRAIL-mediated apoptosis (TRAIL-R3 and -R4). Immobilized anti-TRAIL-R1 or -R2 mAbs were cytotoxic to TRAIL-sensitive tumor cells, whereas tumor cells resistant to recombinant TRAIL were also resistant to these mAbs and only became sensitive when cultured with actinomycin D. The anti-TRAIL-R1 and -R2 mAb-induced death was characterized by the activation of intracellular caspases, which could be blocked by carbobenzyloxy-Val-Ala-Asp (OMe) fluoromethyl ketone (zVAD-fmk) and carbobenzyloxy-Ile-Glu(OMe)-Thr-Asp (OMe) fluoromethyl ketone (zIETD-fmk). When used in solution, one of the anti-TRAIL-R2 mAbs was capable of blocking leucine zipper-human TRAIL binding to TRAIL-R2-expressing cells and prevented TRAIL-induced death of these cells, whereas two of the anti-TRAIL-R1 mAbs could inhibit leucine zipper-human TRAIL binding to TRAIL-R1:Fc. Furthermore, use of the blocking anti-TRAIL-R2 mAb allowed us to demonstrate that the signals transduced through either TRAIL-R1 or TRAIL-R2 were necessary and sufficient to mediate cell death. In contrast, the expression of TRAIL-R3 or TRAIL-R4 did not appear to be a significant factor in determining the resistance or sensitivity of these tumor target cells to the effects of TRAIL.
Animals↗
CYP2D6 polymorphisms in Alzheimer's disease, with and without extrapyramidal signs, showing no apolipoprotein E epsilon 4 effect modification.
BACKGROUND: Allelic variation at the CYP2D6 gene has been reported to be associated with Parkinsons' disease (PD) and Lewy body dementia (LBD), but not with Alzheimer's disease (AD). AD has been associated with apolipoprotein E (apoE) epsilon 4 allele loading. METHODS: We examined CYP2D6 and apoE polimorphisms in a sample of 259 patients with dementia, 210 of whom had a diagnosis of AD, and 107 healthy controls. RESULTS: We found that the allelic frequency in our AD sample did not vary from that in the controls. The debrisoquine hydroxylase poor metabolize phenotype was not more prevalent among AD cases than among controls in contrast to that reported for PD and LBD. We also found that CYP2D6 status does not modify the risk effect for AD conferred by apoE epsilon 4 alleles. CONCLUSIONS: These findings provide some support to the notion that, at a genetic level, at least at this locus, AD could be distinct from PD and LBD.
Age of Onset↗
Molecular cloning and biological characterization of NK cell activation-inducing ligand, a counterstructure for CD48.
Using the monoclonal antibody C1.7, which recognizes a signaling, membrane-bound molecule on human NK and a proportion of CD8(+) T cells, we cloned a novel molecule we refer to as NK cell activation-inducing ligand (NAIL). It is a 365-amino acid protein that belongs to the immunoglobulin-like superfamily with closest homology to murine 2B4, and human CD84 and CD48. Using a soluble NAIL-Fc fusion protein, we determined the counterstructure for NAIL, CD48, which it binds with high affinity. Stimulation of human B cells with recombinant NAIL in the presence of a suboptimal concentration of human CD40 ligand or IL-4 resulted in increased proliferation. Treatment of human dendritic cells with soluble NAIL-leucine zipper protein resulted in an increased release of IL-12 and TNF-alpha. Using recombinant CD48 protein, we demonstrated the ability of this molecule to increase NK cell cytotoxicity and induce IFN-gamma production. We also showed that 2B4 binds to mouse CD48, suggesting that interaction of these receptors may play a similar role in both species. Taken together these results indicate that the NAIL-CD48 interaction may be an important mechanism regulating a variety of immune responses.
Amino Acid Sequence↗
Lifelong estrogen exposure and cognitive performance in elderly women.
Fluctuating endogenous and exogenous estrogens influence cognition in women. In this study, cognitive functioning in elderly women was examined by applying methodology used in understanding the effects of chronic estrogen exposure on hormone-sensitive tissue other than the brain. An index, combining menstrual, reproductive, and physical markers associated with estrogen levels, was developed for elderly, nondemented, predominantly Caucasian women (n = 87). This index related to better performance on two verbal factors, one attentional and one global in nature. Findings suggest that estrogen exposure across the life span plays a role in brain aging. Possible physiological mechanisms for this effect are discussed.
Age Factors↗
Expression of chicken steroidogenic factor-1 during gonadal sex differentiation.
The orphan nuclear receptor, steroidogenic factor-1 (SF-1), regulates steroidogenic enzyme expression and is essential for gonadal and adrenal development in mammals. We have examined expression of the chicken homologue, cSF-1, during gonadal sex differentiation using whole mount in situ hybridisation and RNase protection assays (RPA). In the youngest embryos examined (day 3.5; stages 21-22), cSF-1 transcripts were already detectable by in situ hybridisation in the undifferentiated genital ridge of both sexes. Expression continued in the gonads of both sexes at the time of sexual differentiation (days 5.5-6.5; stages 28-30). Expression then became higher in developing ovaries compared to testes at days 6.5-8. 5 (stages 30-35). At day 13.5 (stage 40), when the gonads are well differentiated, both ovaries and testes showed cSF-1 expression, with higher levels of expression in the left ovary compared to the right (regressing) gonad in females and compared to testes. RPA analysis of isolated gonads confirmed higher expression of SF-1 in differentiating ovaries relative to testes. Expression of cSF-1 in the developing adrenal gland was similar for both sexes at all stages examined. In tissue sections of day 8.5 whole mount gonads, cSF-1 expression was localised in the medulla of the ovary and was weakly detectable in the testis. These observations indicate that SF-1 has a conserved role in early gonadal and adrenal development in vertebrates. However, upregulation of cSF-1 expression during ovarian differentiation is opposite to the pattern seen in mammals, in which SF-1 is downregulated in females. This difference between the birds and mammals may reflect differences in steroidogenic activity of the embryonic ovary versus the testis in the two groups.
Animals↗
Disinfection of tonometers and contact lenses in the office setting: are current techniques adequate?
PURPOSE: To determine whether routine office techniques used to disinfect tonometer prisms and trial contact lenses are sufficient to prevent transmission of ocular infections. METHOD: We reviewed the current literature on the efficacy of certain disinfection protocols against commonly encountered viral, bacterial, and fungal pathogens as well as Acanthamoeba. RESULTS: Some commonly used disinfecting solutions and techniques may be inadequate for disinfection of viruses such as hepatitis C virus and organisms such as Acanthamoeba. When used in accordance with guidelines published by the United States Centers for Disease Control and Prevention (CDC) and the American Academy of Ophthalmology (AAO), 3% hydrogen peroxide is a very effective disinfectant against a wide variety of microorganisms. Specifically, tonometer prisms disinfected by a 5-minute soak in 3% hydrogen peroxide (or 70% isopropyl alcohol or a 1:10 dilution of sodium hypochlorite) are adequately disinfected against most ocular pathogens, with the exception of Acanthamoeba. Trial contact lenses that are disinfected with a 2-hour soak in 3% hydrogen peroxide are effectively rid of all pathogens of concern. After disinfection, rigid lenses should be stored dry, and soft lenses should be stored in a sterile, preserved solution. Repeat disinfection should be routinely performed at 1-month intervals to prevent regrowth of organisms. CONCLUSION: A safe office environment can be maintained by following current CDC recommendations for disinfection, as well as instituting some additional procedures.
Anti-Infective Agents↗
Genetic evolutionary staging of early non-small cell lung cancer: the P53 --> HER-2/NEU --> ras sequence.
INTRODUCTION: The sequence of genetic evolutionary abnormalities that have occurred in a given lung cancer tumor before tumor sampling can be inferred from patterns of intracellular co-occurrence of these abnormalities in tumor cell subpopulations at the time of sampling. The same evolutionary sequences that are present within each lung cancer were evident in intertumor comparisons. METHODS: Correlated cell by cell measurements of cell DNA content, p53, Her-2/neu, and ras proteins were obtained by multiparameter flow cytometry on 46 surgically resected stage I-III primary non-small cell lung cancers. Early evolutionary changes were identified by the fact that they could appear alone in individual cells. Later appearing abnormalities were identified by the fact that they were accompanied by early abnormalities in the same cells. Patients were followed prospectively. Evolutionary patterns observed in individual tumors were correlated with subsequent clinical outcome of patients undergoing surgical resection. RESULTS: Three common patterns were identified: (I) a diploid DNA pathway consisting of the sequence p53 overexpression --> Her-2/neu overexpression --> ras overexpression, (II) an aneuploid DNA pathway with the same p53 --> Her-2/neu --> ras sequence, and (III) a pathway in which none of the intracellular protein measurements made here were abnormal. Fourteen tumors recurred after 11.5 months' median study time. Nine of 12 recurrences in pathways I and II occurred in patients whose tumors were far advanced along these molecular genetic pathways. CONCLUSIONS: Multiparameter cell-based genetic evolutionary studies may be a promising approach for identifying patients with stage I-III non-small cell lung cancer at high risk for recurrence.
Adult↗
Molecular basis for thermoprotection in Bemisia: structural differences between whitefly ketose reductase and other medium-chain dehydrogenases/reductases.
The silverleaf whitefly (Bemisia argentifolii, Bellows and Perring) accumulates sorbitol as a thermoprotectant in response to elevated temperature. Sorbitol synthesis in this insect is catalyzed by an unconventional ketose reductase (KR) that uses NADPH to reduce fructose. A cDNA encoding the NADPH-KR from adult B. argentifolii was cloned and sequenced to determine the primary structure of this enzyme. The cDNA encoded a protein of 352 amino acids with a calculated molecular mass of 38.2 kDa. The deduced amino acid sequence of the cDNA shared 60% identity with sheep NAD(+)-dependent sorbitol dehydrogenase (SDH). Residues in SDH involved in substrate binding were conserved in the whitefly NADPH-KR. An important structural difference between the whitefly NADPH-KR and NAD(+)-SDHs occurred in the nucleotide-binding site. The Asp residue that coordinates the adenosyl ribose hydroxyls in NAD(+)-dependent dehydrogenases (including NAD(+)-SDH), was replaced by an Ala in the whitefly NADPH-KR. The whitefly NADPH-KR also contained two neutral to Arg substitutions within four residues of the Asp to Ala substitution. Molecular modeling indicated that addition of the Arg residues and loss of the Asp decreased the electric potential of the adenosine ribose-binding pocket, creating an environment favorable for NADPH-binding. Because of the ability to use NADPH, the whitefly NADPH-KR synthesizes sorbitol under physiological conditions, unlike NAD(+)-SDHs, which function in sorbitol catabolism.
Aldose-Ketose Isomerases↗
Synthesis, characterization and anticonvulsant activity of enaminones. Part 6: Synthesis of substituted vinylic benzamides as potential anticonvulsants.
A comparison of enaminones from various unsubstituted and p-substituted benzamides to the analogous benzylamines has been undertaken with the aim of elucidating the essential structural parameters necessary for anticonvulsant activity. Initial studies on methyl 4-N-(benzylamino)-6-methyl-2-oxocyclohex-3-en-1-oate, 3a, 3-N-(benzylamino)cyclohex-2-en-1-one, 3p, and 5,5-dimethyl-3-N-(benzylamino)-cyclohex-2-en-1-one, 3r indicated that benzylamines possessed significant anti-maximal electroshock seizure (MES) activity. Evaluation of the analogous benzamides revealed significant differences in anticonvulsant activity, these differences were most probably related to the differences in their three-dimensional structures.
Animals↗
Neuroanatomic substrates of semantic memory impairment in Alzheimer's disease: patterns of functional MRI activation.
Impairment in semantic processing occurs early in Alzheimer's disease (AD) and differential impact on subtypes of semantic relations have been reported, yet there is little data on the neuroanatomic basis of these deficits. Patients with mild AD and healthy controls underwent 3 functional MRI auditory stimulation tasks requiring semantic or phonological decisions (match-mismatch) about word pairs (category-exemplar, category-function, pseudoword). Patients showed a significant performance deficit only on the exemplar task. On voxel-based fMRI activation analyses, controls showed a clear activation focus in the left superior temporal gyrus for the phonological task; patients showed additional foci in the left dorsolateral prefrontal and bilateral cingulate areas. On the semantic tasks, predominant activation foci were seen in the inferior and middle frontal gyrus (left greater than right) in both groups but patients showed additional activation suggesting compensatory recruitment of locally expanded foci and remote regions, for example, right frontal activation during the exemplar task. Covariance analyses indicated that exemplar task performance was strongly related to signal increase in bilateral medial prefrontal cortex. The authors conclude that fMRI can reveal similarities and differences in functional neuroanatomical processing of semantic and phonological information in mild AD compared to healthy elderly, and can help to bridge cognitive and neural investigations of the integrity of semantic networks in AD.
Aged↗
Determination of fibrosis from cryostat sections using high performance liquid chromatography: skeletal muscle.
Analysis of hydroxyproline (collagen) and pyridinoline (collagen cross-links) in biopsies prepared for routine histological evaluation with OCT compound was performed. Frozen sections (250 microm-thick) were cut from cardiac muscle, diaphragm, liver, and soleus muscle from the rat. After removal of OCT compound by rinsing, the samples were dried, weighed and hydrolyzed in 6 N HCl. A portion of the hydrolysate was analyzed for hydroxyproline using high performance liquid chromatography with collagen type I as the standard. Collagen concentrations ranged from 6.6 microg/mg dry weight (liver) to 74.7 microg/mg dry weight (diaphragm). From the remainder of the hydrolyzate, pyridinoline cross-links of collagen were separated and analyzed similarly by high performance liquid chromatography. The concentration of pyridinoline ranged from 2.6 ng/mg dry weight (liver) to 35.6 ng/mg dry weight (diaphragm). These techniques were adequate to analyze both collagen and pyridinoline (i.e. collagen cross-links) in small biopsy samples (< 1 mg dry weight) routinely used in clinical pathology. The method proved useful in the quantitation of focal fibrosis in a partially denervated rat soleus. Denervation was confirmed using fast myosin immunohistochemistry which revealed large areas of small myofibres containing fast myosin. Collagen concentration increased by five-fold and collagen cross-links by more than 7-fold consistent with fibrotic changes known to occur with denervation.
Amino Acids↗