Cardiovascular disease risk factors in chronic renal insufficiency

BACKGROUND

Coronary heart disease (CHD) is an important cause of morbidity and mortality in end-stage renal disease (ESRD). Prevention of CHD in ESRD requires identification and treatment of coronary risk factors in chronic renal insufficiency (CRI).

METHODS

We evaluated the prevalence of "traditional coronary risk factors" in CRI in 1,795 patients enrolled in the baseline period of Modification of Diet in Renal Disease (MDRD) Study. Using a cross-sectional design, we determined the relationship of these risk factors to the level of glomerular filtration rate (GFR) and proteinuria. We also predicted the CHD risk in the MDRD Study baseline cohort using the coronary point score.

RESULTS

64.0% had blood pressure > or = 130/85 mmHg despite antihypertensive therapy. 64.2% had LDL cholesterol > or = 130 mg/dl, while 38.3% had HDL cholesterol < 35 mg/dl. After adjustment for age, gender and the presence of diabetes, GFR was inversely associated with systolic blood pressure and positively associated with HDL cholesterol, but not associated with total or LDL cholesterol. After adjustment for age. gender and the presence of diabetes, proteinuria was positively associated with systolic and diastolic blood pressure, total serum cholesterol and LDL cholesterol, and inversely associated with HDL cholesterol. Nonetheless, the predicted CHD risk, even at a very low GFR, was similar to the risk in the general population and lower than the observed rate of de novo CHD in incident dialysis patients.

CONCLUSIONS

"Traditional coronary risk factors" are highly prevalent in CRI and vary with the level of renal function. However, the coronary point score does not appear to explain the extent of increased CHD risk in ESRD. Non-traditional risk factors may also contribute to CHD in ESRD.

Directional responses of basal optic neurons are modulated by the nucleus lentiformis mesencephali in pigeons

The nucleus lentiformis mesencephali (nLM) and the nucleus of the basal optic root (nBOR) in pigeons are both involved in optokinetic nystagmus. They are reciprocally connected and thus may interact with each other. The present study injected lidocaine into nLM and then examined the effects of nLM blockade on visual responses of nBOR neurons to target motion. The results indicate that nLM could modulate nBOR activity in two ways. First, nLM enhances visual responses of 70% of nBOR cells to motion in the preferred directions, sharpening their directional tuning. Second, nLM reduces visual responses of 13% of nBOR cells to motion in the preferred directions, broadening their directional tuning. The remaining 17% of nBOR cells are not affected by drug application. Taken together with the previous results that nBOR could modulate nLM activity (Gu et al., Neuroscience, 104 (2001) 153), it suggests that both nuclei can mutually modulate each other in generating optokinetic nystagmus.

Directional modulation of visual responses of pretectal neurons by accessory optic neurons in pigeons

The nucleus lentiformis mesencephali and the nucleus of the basal optic root in birds, homologous to the nucleus of the optic tract and the terminal nuclei of the accessory optic tract in mammals, are involved in optokinetic nystagmus. The present study provides the first electrophysiological evidence that reversible blockade of the pigeon nucleus of the basal optic root by lidocaine can change visual responsiveness of pretectal neurons in a direction-dependent manner. Thirty pretectal cells examined were classified as unidirectional (80%), bidirectional (10%) and omnidirectional (10%) cells according to their directional selectivity. Among the unidirectional cells, seven cells changed firing rates in all directions of motion, 11 changed visual responses only in the preferred directions and six others did not change their responsiveness during lidocaine. Most of the bidirectional cells changed firing rates in the temporonasal direction, and two-thirds of the omnidirectional cells showed these changes in all directions. Thirteen lidocaine administration sites were marked within the nucleus of the basal optic root and 19 recording sites were marked within the nucleus lentiformis mesencephali. This histological verification indicates that the effects of lidocaine blockade in the accessory optic nucleus on the directional selectivity and visual responsiveness of pretectal cells appear to be related, to some extent, to the location of drug injections in the nucleus of the basal optic root. This study has found that visual neurons in the nucleus of the basal optic root, which predominantly prefer vertical and backward motion, could modulate the directional selectivity and visual responsiveness of neurons in the nucleus lentiformis mesencephali, which mainly prefer horizontal motion. It is conceivable that both nuclei work together in coordination and in competition during optokinetic nystagmus.

Firing patterns and morphological features of neurons in the pigeon nucleus rotundus

In birds, the thalamic nucleus rotundus relays visual information from the midbrain optic tectum to the forebrain ectostriatum. Using brain slices, the present study investigates the firing patterns and morphological features of 41 neurons in various divisions of the pigeon nucleus rotundus. The results indicate that these rotundal cells could be physiologically categorized into two types according to their firing patterns in response to depolarizing current pulses. Type I cells (76%) are characterized by a multi-phase firing pattern producing a single spike, late-spiking and fast-spiking as current intensity increases. Cells of type II (24%) are characterized by a rapid spiking-inactivation, discharging only one or two small spikes at the onset of current injections. However, intracellular staining shows no significant morphological differences between the two physiological types of cells in terms of somatic and dendritic field sizes, or an average density of dendritic varicosities, although each cell type includes both small- and large-sized dendritic fields. It is likely that the firing patterns and morphological features of rotundal neurons might not be correlated with each other or with rotundal divisions.

Electrophysiological and anatomical evidence for a direct projection from the nucleus of the basal optic root to the nucleus rotundus in pigeons

A direct projection of the nucleus of the basal optic root (nBOR) onto the nucleus rotundus (Rt) in the pigeon would link the accessory optic system to the ascending tectofugal pathway and could thus combine self- and object-motion processes. In this study, injections of retrograde tracers into the Rt revealed some cells in central nBOR to project onto the ipsilateral Rt. Contrary, injections into the diencephalic component of the ascending thalamofugal pathway resulted in massive labeling of neurons in dorsal nBOR. Single unit recordings showed that visual nBOR units could be activated by antidromic stimulation through the Rt. Successful collision tests applied to nBOR cells revealed that the connection between nBOR and Rt is direct. These data provide strong evidence for a direct and differential projection of nBOR subcomponents onto the thalamic relays of the two ascending visual pathways.

Effects of BCG on ovalbumin-induced bronchial hyperreactivity in a guinea pig asthma model

To test the effects of Bacillus Calmette-Guérin (BCG) on ovalbumin (OVA)-induced airway hyper-reactivity in guinea pigs, a total of 40 young guinea pigs was individually vaccinated subcutaneously with 0.2 mL of 2% OVA, 50 microg BCG, or a mixture of OVA and BCG (OVA+BCG). Airways were sensitized using nebulization with 1% OVA for 3 min once a week for two applications, followed by 2% OVA nebulized challenge for 3 min 1 week after the last application. Different concentrations of methacholine were used to detect airway hyperreactivities. At the third week, the guinea pigs were nebulized with either methacholine or OVA to test airway hyperreactivity. The OVA-vaccinated group presented with severe airway hyperresponsiveness after OVA and methacholine challenges; the BCG-vaccinated group showed mild airway hyperreactivity; and the OVA+BCG group showed the least amount of airway hyperreactivity. Lung histopathology in all groups, except the OVA+BCG-vaccinated group, showed severe thickening of the alveolar walls which became firmly fibrotic, and narrowing of the alveolar spaces was also noted. The guinea pigs in the OVA+BCG-vaccinated group had similar pulmonary morphology with that of naive guinea pigs, and had mild cell infiltration in the alveolar wall. The results of the skin biopsies at 6 h (2% OVA, 0.05 mL) and 36 h (20 microg PPD, 0.05 mL) after purified protein derivative (PPD) inoculation showed that infiltration of eosinophils and activation of CD4+ T-cells occurred in the OVA-vaccinated group. In the BCG-vaccinated groups, infiltration of CD4+ T-cells, CD8+ T-cells and macrophages occurred. OVA-specific IgG2 increased in the BCG-vaccinated groups after OVA-induced airway hyperreactivity occurred. The peripheral cell subpopulation showed that there was obviously increased activation of CD4+ and CD8+ T-cells in the OVA+BCG-vaccinated group. The phagocytic activity of macrophages also increased in both BCG- and OVA+BCG-vaccinated groups. The prevention of OVA-induced airway hyperreactivities using BCG vaccination in conjugation with OVA in these young guinea pigs indicated that it might be a good approach to avoid allergic reactions in humans.

Tecto-isthmo-optic transmission in pigeons is mediated by glutamate and nitric oxide

The isthmo-optic nucleus of the centrifugal system in birds receives primarily input from the ipsilateral tectum and projects to the contralateral retina. The present study using brain slices and microiontophoresis shows that synaptic transmission from the tectum to the centrifugal nucleus in pigeons is excitatory. About 75% of tecto-isthmo-optic fibers are glutamatergic, mediated by alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid but not N-methyl-D-aspartate-receptors, and 25% of others may use nitric oxide as a transmitter or modulator. On the other hand, about 60% of isthmo-optic cells receive glutamatergic afferents, 20% receive nitric oxidergic afferents, and 20% of others receive both glutamatergic and nitric oxidergic afferents from the tectum. In the last group, it is more likely that both glutamate and nitric oxide may co-release from the same tecto-isthmo-optic terminals. All the isthmo-optic cells examined in the present study also receive gamma-aminobutyric acid (GABA)ergic afferents via GABA(A) and GABA(B) receptors probably from some extratectal structures.

Serine protease isoforms of Deinagkistrodon acutus venom: cloning, sequencing and phylogenetic analysis

The major coagulating fibrinogenase of Deinagkistrdon acutus venom, designated acutobin, was purified by anion-exchange chromatography, gel filtration and reverse-phase HPLC. Approximately 80% of its protein sequence was determined by sequencing the various fragments derived from CNBr cleavage and digestion with endoprotease. Extensive screening of the venom gland cDNA species after amplification by PCR resulted in the isolation of four distinct cDNA clones encoding acutobin and three other serine proteases, designated Dav-PA, Dav-KN and Dav-X. The complete amino acid sequences of these enzymes were deduced from the cDNA sequences. The amino-acid sequence of acutobin contains a single chain of 236 residues including four potential N-glycosylation sites. The purified acutobin (40 kDa) contains approx. 30% carbohydrate by weight, which could be partly removed by N-glycanase. The phylogenetic tree of the complete amino acid sequences of 40 serine proteases from 18 species of Crotalinae shows functional clusters reflecting parallel evolution of the three major venom enzyme subtypes: coagulating enzymes, kininogenases and plasminogen activators. The possible structural elements responsible for the functional specificity of each subtype are discussed.

Identification of vacuolar serine proteinase as a major allergen of Aspergillus fumigatus by immunoblotting and N-terminal amino acid sequence analysis

Aspergillus species are common airborne fungi that have been identified as causative agents of extrinsic bronchial asthma. More than 10 allergens from A. fumigatus have been recently characterized by cDNA cloning. The objective of this study is to identify A. fumigatus allergens through immunoblot analysis using sera from asthmatic patients. IgE-binding components of A. fumigatus and IgE cross-reactivity among allergens of different prevalent airborne fungal species were analysed by immunoblot and immunoblot inhibition, respectively, using sera from asthmatic patients. The N-terminal amino acid sequences of major allergens identified were determined by Edman degradation. Among two batches (70 and 41 sera) of asthmatic sera tested, 19 (27%) and 14 (34%), respectively, have IgE immunoblot reactivity towards components of A. fumigatus. A 34-kDa protein that reacts with IgE antibodies in 15 (79%) and 11 (79%) of the 19 and 14 positive samples, respectively, may be considered a major allergen of A. fumigatus. The N-terminal amino acid sequences of the 34 kDa major allergen and the 30.5 and 30 kDa IgE-binding components of A. fumigatus showed sequence identity to that of the vacuolar serine proteinase from A. fumigatus. The results from immunoblot inhibition show IgE cross-reactivity among major allergens of A. fumigatus, P. notatum and P. oxalicum. Results obtained suggest that the 34 kDa major allergen of A. fumigatus may be a vacuolar serine proteinase. There is IgE cross-reactivity among serine proteinase allergens of A. fumigatus, P. notatum and P. oxalicum.

Visual responses of neurons in the pretectal nucleus lentiformis mesencephali to moving patterns within and beyond receptive fields in pigeons

Large-field patterns are effective stimuli for eliciting visual responses from neurons in the pretectal nucleus lentiformis mesencephali of nonmammals. The present study shows that stimulation beyond the receptive field does not contribute to the visual responses of neurons in the nucleus lentiformis mesencephali in two respects. First, changes in the direction and velocity of motion beyond the receptive field did not affect the visual responses of the pretectal cells to motion within the receptive field. Second, time differences in the onset of stimulation within and outside the receptive field did not influence the visual responses of the pretectal cells to motion in the receptive field, implying that there may be no long-range interaction between the receptive field and its surrounding field. The present study also indicates that the pretectal cells are not only sensitive to the direction and velocity of motion, but also to the size and density of dots in a random-dot pattern moving through the receptive field. Taken together with previous studies, these results suggest that the receptive field of the pretectal cells within the nucleus lentiformis mesencephali is large in size but well defined in boundaries, and that the pretectal cells respond to motion of visual stimuli within but not beyond their receptive fields.

cDNA cloning and immunologic characterization of Pen o 18, the vacuolar serine protease major allergen of Penicillium oxalicum

Penicillium species are prevalent indoor airborne fungi that have been identified as causative agents of human extrinsic bronchial asthma. In the preparation of standardized diagnostic reagents, it is imperative to define the allergens of these ubiquitous fungi. Results from our previous study on P. oxalicum suggest that the 34-kd major immunoglobulin E-reacting component of this prevalent Penicillium species is probably a vacuolar serine protease. The purpose of the present study was to define this major P. oxalicum allergen (Pen o 18) through cDNA cloning and immunologic characterization. The cDNA of Pen o 18 was isolated through a combination of reverse transcriptase-polymerase chain reaction and 5'- and 3'-rapid amplification cDNA ends reactions. The primers used in these reactions were constructed according to the internal amino acid sequences of Pen o 18 and the conserved amino acid sequences of fungal serine proteases. Our results showed that a 1897-bp cDNA with an open reading frame of 503 residues was isolated for the proenzyme of Pen o 18. The encoded protein has a 16-residue signal peptide and a 119-residue prosequence. On maturation, the protein has an N-terminal glutamate that is the 136th residue encoded by the cDNA. Apparently the precursor also undergoes C-terminal processing with the cleavage of about 47 amino acids. The cDNA for Pen c 18 (the vacuolar serine protease allergen from P. citrinum ) was also isolated for comparison. Contrary to a previous report, the C-terminal region of Pen c 18 is similar to that of Pen o 18. Recombinant proteins (rPen o 18 and rPen c 18) with the putative mature N-termini and a his-tag were obtained by expressing the corresponding cDNAs in Escherichia coli. Serum samples from 7 asthmatic patients with immunoglobulin E reactivity to the 34-kd component of P. oxalicum also react to his-tagged recombinant Pen o 18. The presence of immunoglobulin E cross-reactivity between rPen o 18 and rPen c 18 was detected by immunoblot inhibition. Two monoclonal antibodies (PCM39 and FUM20) against fungal serine proteases react with rPen o 18, rPen c 18, and the 35/34-kd components in the corresponding crude fungal extracts. These components also react with immunoglobulin E antibodies in serum samples from asthmatic patients. In conclusion, results obtained confirm that the 34-kd major allergen of P. oxalicum is a vacuolar serine protease. The cDNAs of Pen o 18 and Pen c 18 encode precursor molecules that appear to undergo both N-terminal and C-terminal processing. Constructs beginning with mature N-terminal can be expressed in E. coli to produce recombinant polypeptides that are reactive to monoclonal antibodies or immunoglobulin E antibodies in serum samples from asthmatic patients. Results obtained may provide useful information and materials for preparation of standardized diagnostic reagents in clinical mold allergy.

Modulatory effects of the nucleus of the basal optic root on rotundal neurons in pigeons

The present paper reports for the first time in birds the modulatory effects of the nucleus of the basal optic root (nBOR) on visual neurons in the nucleus rotundus in particular and those of the accessory optic system on the tectofugal pathway in general. Pharmacological blockade of the nBOR by lidocaine led to a decrease or increase in visual responsiveness of rotundal cells, suggesting excitatory or inhibitory actions of the nBOR on rotundal cells. These results were confirmed by changes in the excitability of rotundal cells following electrical stimulation of the nBOR. Response latency measurements implied that there might be at least two pathways from the nBOR to the nucleus rotundus, one being a direct excitatory pathway and the other an indirect inhibitory pathway possibly mediated by the subpretectal nucleus and the interstitio-pretecto-subpretectal nucleus, which have been thought to send inhibitory afferents to the nucleus rotundus. Taken together with previous neuroanatomical and immunocytochemical studies, it is suggested that modulatory interactions might exist between the nBOR and the nRt in particular and between the accessory optic system and the tectofugal pathway in general in birds.

Glutamatergic neurotransmission from the optic tectum to the contralateral nucleus rotundus in pigeons

Neuronal responses of 114 cells to electrical stimulation of the optic tectum were extracellularly recorded from the contralateral nucleus rotundus (nRt) in pigeons (Columba livia), and the effects of two glutamatergic antagonists CNQX and CPP, as well as those of GABA, were examined on rotundal cells. The results show that tectal stimulation evokes excitation in neurons of the contralateral nRt and that the excitatory responses are blocked by microiontophoretically applied CNQX, CPP and GABA. It is suggested that the contralateral tectorotundal transmission is excitatory in nature and mediated by both glutamatergic AMPA and NMDA receptors and that GABA is an inhibitory transmitter within the nucleus as well. We also review our previous findings in discussing transmitters participating in the tectofugal pathway.

Serum and milk lactoferrin concentration and the correlation with some blood components in lactating sows

An increased serum concentration of lactoferrin is associated with inflammatory disease, but there are few reported data on this aspect for lactating sows. Samples of blood and milk were collected from 17 lactating sows under minimum stress conditions and analysed for lactoferrin. Lactoferrin concentrations in serum and milk were positively correlated, being high after farrowing and steadily decreasing throughout 28 days of lactation. A positive linear correlation was observed between lactoferrin concentration and enzyme activities of alanine aminotransferase, lactate dehydrogenase, and hydroxybutyrate dehydrogenase in the serum indicating post-partum inflammation. Serum and milk lactoferrin concentrations, although closely correlated, may be regulated through independent systems activated simultaneously.

Excitatory and inhibitory receptive fields of tectal cells are differentially modified by magnocellular and parvocellular divisions of the pigeon nucleus isthmi

It has been known that magnocellular and parvocellular divisions of the pigeon nucleus isthmi exert excitatory and inhibitory actions on tectal cells, respectively. The present study shows that injection of N-methyl-D-aspartate into the parvocellular division results in an increase in responsive strength and extent of the inhibitory receptive fields, which expand into the excitatory receptive fields of tectal cells. This injection concurrently leads to a decrease in responsiveness and extent of the excitatory fields. On the other hand, injection of acetylcholine into the magnocellular division enhances visual responsiveness, although the excitatory field is not obviously changed in extent. Meanwhile, strength and extent of the inhibitory fields are decreased by acetylcholine. The excitatory and inhibitory fields are reduced in both strength and extent by magnocellular and parvocellular injection of lidocaine, respectively. It suggests that isthmic inputs from both parvocellular and magnocellular divisions converge onto the same tectal cells, and the magnocellular and parvocellular subnuclei can modulate excitatory and inhibitory receptive fields of tectal cells, respectively, with some interactions between both fields.

Developmental changes of NADPH-diaphorase positive structures in the isthmic nuclei of the chick

Nicotine adenine dinucleotide phosphate-diaphorase staining was used to study nitric oxide synthase activity and distribution in the midbrain visual structures of white leghorn chick embryos and post-hatched chickens. Enzyme staining first appeared in the isthmic region at the tenth embryonic day (E10) in the neuropil of the nucleus isthmi, pars parvocellularis. At E11 faint enzyme positivity appeared also in the nucl. isthmi pars magnocellularis, the nucl. semilunaris and the nucl. isthmo-opticus. The staining intensity of the isthmic nuclei dramatically increased between the 12.5th and the 13th days of incubation. The nucl. isthmi, pars parvocellularis showed the strongest enzyme reaction throughout embryonic life. A day before hatching all the isthmic nuclei were heavily stained, however, nicotine adenine dinucleotide phosphate-diaphorase-positive cells occurred exclusively in the nucleus isthmo-opticus. In the tectum opticum, intensely stained cells occupied the stratum fibrosum et griseum superficiale. The layer containing the projection neurons to the isthmo-optic nucleus was unstained. In the isthmic region, the intensity of staining surpassed that of the tectum and reached its maximum at E17 and then slowly decreased till the end of the experimental period (120 days post-hatched). The tractus isthmo-opticus showed nicotine adenine dinucleotide phosphate-diaphorase activity throughout the investigated period of life of the chicken, but the tractus tectoisthmo-opticus was unstained. Our results suggest that in the isthmic nuclei, nicotine adenine dinucleotide phosphate-diaphorase-positive neurons occur only in the isthmo-optic nucleus and optic tectum. The other positively stained structures are the fibers and terminals of tectal cells. In most brain areas nicotine adenine dinucleotide phosphate-diaphorase indicates nitric oxide synthase that produces nitric oxide. The transient appearance of this molecule is probably necessary for neuronal differentiation or the establishment of synaptic connections in the isthmic nuclei, and these developmental changes are under the control of the optic tectum.

[Action of fengsuidan granules on experimental anti-oral ulcer]

OBJECTIVE

To explore the anti-oral ulcer action, anti-inflammatory and analgesic effect of Fengsuidan Granules(FSDG).

METHODS

FSDG(0.5, 5.0, 10.0 g.kg-1) were administered to experimental animals. The oral ulcer in experimental animals was effected by means of white staphylococcus (sc) and carbolic acid (buming).

RESULTS

Such as acetic acid body turning, hot-plate, auricle inflammation by dimethylbenzene and foot swelling by egg white were used.

CONCLUSION

Following certain regularities of dose-effect relationship, FSDG has anti-oral ulcer effect, helps reduce and heal the ulcer and works efficaciously in analgesic and anti-inflammatory cases.

Complementary DNA cloning and immunologic characterization of a new Penicillium citrinum allergen (Pen c 3)

BACKGROUND

Penicillium citrinum has been identified as the most prevalent airborne Penicillium species in the Taipei area. It is important to understand the allergenic composition of this ubiquitous fungal species.

OBJECTIVE

The complementary DNA (cDNA) clone of an allergen from P citrinum was isolated and expressed in Escherichia coli as a fusion protein. mAbs were prepared with the recombinant protein as antigen. The corresponding natural allergen in the fungal extracts was identified with the mAbs.

METHODS

A Uni-Zap XR P citrinum cDNA library was screened with sera from asthmatic patients. An IgE-binding cDNA clone was isolated and expressed as a glutathione-S-transferase fusion protein. The frequency of IgE binding to the expressed protein was analyzed by immunoblotting. Spleen cells from BALB/c mice immunized with the recombinant protein were fused with NS-1 cells for mAb generation.

RESULTS

A P citrinum cDNA library was screened with a mixture of serum samples from 4 asthmatic patients. An IgE-binding cDNA clone was obtained and designated as PCE2. PCE2 has a 694-bp insert that contains a 167 amino acids open reading frame. The deduced amino acid sequence of the encoded protein has 82.6% (138 amino acids) identity with an Aspergillus fumigatus peroxisomal membrane protein allergen (Asp f 3). PCE2 was expressed in E coli as a fusion protein and designated as Pen c 3. Sera from 13 (46%) of the 28 Penicillium-sensitized asthmatic patients demonstrated IgE binding to Pen c 3. In addition, 11 of the 13 Pen c 3-positive serum samples have IgE immunoblot reactivity to recombinant Asp f 3. The presence of IgE cross-reactivity between Pen c 3 and Asp f 3 was also detected by immunoblot inhibition. Four of the 6 mAbs generated against Pen c 3 cross-react with Asp f 3. The presence of the corresponding 18-k natural allergens in the crude extracts of P citrinum and A fumigatus were detected by immunoblot with use of the mAbs and sera from asthmatic patients.

CONCLUSION

Results obtained suggest that the peroxisomal membrane protein (Pen c 3) is an important allergen of P citrinum. PCE2 is a full-length cDNA clone encoding this allergen. In addition, the mAbs generated may be useful in standardizing the diagnostic allergenic extracts.

Relationship between nutritional status and the glomerular filtration rate: results from the MDRD study

BACKGROUND

The relationship between the protein-energy nutritional status and renal function was assessed in 1785 clinically stable patients with moderate to advanced chronic renal failure who were evaluated during the baseline phase of the Modification of Diet in Renal Disease Study. Their mean +/- SD glomerular filtration rate (GFR) was 39.8 +/- 21.1 mL/min/1.73 m2.

METHODS

The GFR was determined by 121I-iothalamate clearance and was correlated with dietary and nutritional parameters estimated from diet records, biochemistry measurements, and anthropometry.

RESULTS

The following parameters correlated directly with the GFR in both men and women: dietary protein intake estimated from the urea nitrogen appearance, dietary protein and energy intake estimated from dietary diaries, serum albumin, transferrin, percentage body fat, skinfold thickness, and urine creatinine excretion. Serum total cholesterol, actual and relative body weights, body mass index, and arm muscle area also correlated with the GFR in men. The relationships generally persisted after statistically controlling for reported efforts to restrict diets. Compared with patients with GFR > 37 mL/min/1.73 m2, the means of several nutritional parameters were significantly lower for GFR between 21 and 37 mL/min/1.73 m2, and lower still for GFRs under 21 mL/min/1.73 m2. In multivariable regression analyses, the association of GFR with several of the anthropometric and biochemical nutritional parameters was either attenuated or eliminated completely after controlling for protein and energy intakes, which were themselves strongly associated with many of the nutritional parameters. On the other hand, few patients showed evidence for actual protein-energy malnutrition.

CONCLUSIONS

These cross-sectional findings suggest that in patients with chronic renal disease, dietary protein and energy intakes and serum and anthropometric measures of protein-energy nutritional status progressively decline as the GFR decreases. The reduced protein and energy intakes, as GFR falls, may contribute to the decline in many of the nutritional measures.

Feature detection of visual neurons in the nucleus of the basal optic root in pigeons

Previous studies have shown that the nucleus of the basal optic root in birds is involved in optokinetic nystagmus, and its neurons respond not only to large-field stimuli but also to a single object moving through their excitatory receptive fields. The present study provides electrophysiological evidence that basal optic neurons in pigeons respond vigorously to motion of a black leading edge. The orientation of the edge is also an essential factor affecting visual responses of these cells, showing that any deviation of the edge from the direction perpendicular to the preferred direction decreases visual responses in most cases. Furthermore, visual responses increase as the edge is lengthened within the excitatory receptive field. However, a square, semicircle and isosceles with an area ratio of 1.00: 0.39: 0.50 but with an identical leading edge elicit almost the same responses, which are not dependent on the shape and area of visual stimuli. It suggests that these feature extraction properties, similar to those of neurons in the nucleus lentiformis mesencephali, may be specialized for detecting optokinetic stimuli rich in luminance contrasts, but not for realizing pattern recognition.

Electrical interaction between neurons in the pigeon isthmo-optic nucleus

The present study used brain slices to investigate interneuronal communication in the isthmo-optic nucleus in pigeons. Electrical stimulation of the isthmo-optic tract generated a transmembrane potential in isthmo-optic cells that was obtained by subtracting the extracellular potential from the intracellular potential. This transmembrane potential resulted in enhancement of excitability and/or in production of spikes in 42 (63%) cells. In most cases, proximal axons marked in brain slices by Lucifer yellow were too short to reach the stimulation site, indicating that spikes were evoked by electrical field effect or ephaptic interaction produced by nearby cells whose axons were activated by stimulation. Eleven (16%) cells discharged a spikelet, or spike that was abolished by hyperpolarizing current injection leaving a spikelet. Markings of five of these cells all indicated the presence of dye-couplings, each of which consisted of a pair of cells. Fourteen (21%) cells only produced antidromic spikes with a short and constant latency. Four of these cells were marked and their axons passed through the stimulation site, implying that their nearby cells' axons might be cut too short to be electrically stimulated or they were in a sparse-cell area. The present results provide electrophysiological and neuroanatomical evidence that both electrical field effect and electrical coupling may play important roles in interneuronal communication within the pigeon isthmo-optic nucleus. These findings are supported by anatomical arrangement of densely packed cells and their oriented dendrites in this centrifugal nucleus.

Dual actions of isthmic input to tectal neurons in a reptile, Gekko gekko

We analyzed postsynaptic potentials and dye-labeled morphology of tectal neurons responding to electrical stimulation of the optic nerve and of the nucleus isthmi in a reptile, Gekko gekko, in order to compare with previously reported interactions between the optic tectum and the nucleus isthmi in amphibians and birds. The results indicate that isthmic stimulation exerts inhibitory and excitatory actions on tectal cells, similar to dual isthmotectal actions in amphibians. It appears that dual actions of the isthmotectal pathway in amphibians and reptiles are shared by two subdivisions of the nucleus isthmi in birds. The morphology of tectal cells responding to isthmic stimulation is generally similar to that of tectoisthmic projecting neurons, but they differ particularly in that some tectoisthmic cells bear numerous varicosities whereas cells receiving isthmic afferents do not. Thus, it is likely that at least some tectoisthmic cells may not be in the population of tectal cells that can be affected by isthmic stimulation. Forty-four percent of injections resulted in dye-coupled labeling, suggesting extensive electrical connections between tectal cells in reptiles.

Alkaline serine proteinase is a major allergen of Aspergillus flavus, a prevalent airborne Aspergillus species in the Taipei area

BACKGROUND

Aspergillus species are prevalent indoor airborne fungi and have been identified to be a causative agent of human allergic disorders. In the present study, we identified, purified and characterized the allergen(s) from Aspergillus flavus, a predominant airborne Aspergillus species in the Taipei area.

METHODS

The IgE-binding components of A. flavus were identified by SDS-PAGE immunoblotting with sera from asthmatic patients. The N-terminal amino acid sequences of the major allergens were determined by Edman degradation. The allergenic cross-reactivity among allergens from different fungi was analyzed by immunoblot inhibition using sera from asthmatic patients. The detected major allergen was purified from the culture medium. It was further characterized in terms of its N-terminal amino acid sequence, its IgE-binding activity and its enzymatic activity.

RESULTS

The results of the immunoblot analysis indicate that a 34-kD component that has high IgE-binding (63%) frequency is a major allergen of A. flavus. The N-terminus of this 34-kD major allergen (GLTTQKSAP) has high sequence identity with that of the 34-kD alkaline serine proteinase major allergen of A. oryzae. Results from immunoblot inhibition studies indicate that IgE cross-reactivity occurs among the 34-kD major allergens of A. flavus, A. fumigatus and Penicillium citrinum. The 34-kD major allergen of A. flavus was purified from the culture medium by ammonium sulfate precipitation and DEAE ion exchange chromatography. The N-terminal amino acid sequence of the purified allergen (Asp fl 13) is identical to that determined previously for the 34-kD major allergen in the crude extract of A. flavus. The IgE immunoblot reactivity to the 34-kD major allergen in the crude extract can be dose-dependently inhibited by the purified Asp fl 13. The degree of IgE binding to the 34-kD major allergen in the crude extract correlates with that of the purified Asp fl 13 in sera of 8 asthmatic patients. The purified Asp fl 13 has proteolytic activity with casein as substrate at pH 8.0. This enzymatic activity can be inhibited by either phenylmethylsulfonyl fluoride or diethylpyrocarbonate.

CONCLUSION

Our results suggest that the 34-kD alkaline serine proteinase is a major allergen of A. flavus. There was IgE cross-reactivity among allergens of A. flavus, A. fumigatus and P. citrinum.

Tectal afferents monosynaptically activate neurons in the pigeon isthmo-optic nucleus

Postsynaptic responses of 105 neurons in brain slices were intracellularly recorded from the isthmo-optic nucleus (ION) in pigeons, and 18 of these neurons were labeled with Lucifer yellow. Excitatory postsynaptic potentials (EPSPs) or spikes were produced in 93 cells, inhibitory postsynaptic potentials (IPSPs) in 10 cells, and EPSPs followed by IPSPs in two cells following electrical stimulation of the tecto-isthmooptic tract. The EPSPs occurred in an all-or-none fashion, with short latencies (1.3 +/- 0.6 ms). Repetitive stimulation increased their amplitude and duration, demonstrating that temporal summation was involved. Neurons producing excitatory responses were distributed throughout cellular layers of the nucleus. Pure IPSPs had a latency of 3.9 +/- 2.3 ms, and cells that responded in this manner were only distributed in the rostral portion of the nucleus. In the remaining two cells with EPSP-IPSP responses, the latency of excitatory responses was 1.5 ms in one cell and 1.4 ms in the other, and that of inhibitory responses was, respectively, 5.1 and 4.1 ms. Thus, it appeared that excitation was monosynaptic, whereas inhibition may be polysynaptic. Four single injections resulted in dye-coupled labeling, and two pairs of closely apposed cells fired spikes, probably resulting from spatial summation of their excitatory responses. The present study suggests that tectal cells directly activate ION neurons and that tectal fibers contact isthmo-optic neurons in a one-to-one fashion. Taken together with previous studies, it appears that the entire tecto-ION-retinal pathway is excitatory.

Receptive field characteristics of neurons in the nucleus of the basal optic root in pigeons

Optokinetic nystagmus is a reflex to stabilize an object image on the retina by compensatory eye movements. In lower vertebrates, the nucleus of the basal optic root participates in generating this reflex. Visual responses of 135 neurons were extracellularly recorded from the nucleus in pigeons and their receptive field properties were analysed on-line with a workstation. These cells could be categorized into slow (84%), intermediate (3%) and fast (13%) cells, preferring motion velocities of 0.25-8, 16 and 32-64 deg./s, respectively. Using whole-field gratings as stimuli revealed that 97% of the cells were selective for direction of motion and 3% were not. The directional cells preferred motion in the dorsoventral (35%), nasotemporal (34%), ventrodorsal (23%), or temporonasal (8%) directions. The omni-directional neurons were equally excited or inhibited by motion in all directions. The receptive field of basal optic neurons usually consisted of an excitatory receptive field and an inhibitory receptive field, both of which possessed opposite (heterodirectional) or identical (homodirectional) directionalities. In the case of homodirectional co-existence of both fields, whether whole-field gratings could produce visual responses from the cells would depend on the interaction between excitation and inhibition evoked in their excitatory and inhibitory receptive fields, respectively. Therefore, in some cases a single object was more effective than whole-field gratings in eliciting visual responses from basal optic neurons in pigeons. All of these receptive field properties revealed by on-line computer analysis may underlie the detection of optic flow and the induction of optokinetic responses.