Adrenergic influence on rat plasma concentrations of tyrosine and tryptophan

Isoprenaline given to rats in doses between 0.08 and 10 mg/kg intraperitoneally caused a significant decrease in plasma concentrations of tyrosine and tryptophan. Low doses of adrenaline (0.04 ? 0.16 mg/kg, intraperitoneally) caused a 30 per cent decrease in plasma concentrations of tyrosine, while high doses (0.63 ? 1.25 mg/kg, intraperitoneally) caused an increase in plasma tyrosine to nearly 200 per cent of the controls. High doses of noradrenaline (0.63 ? 2.5 mg/kg, intraperitoneally) caused a similar increase in plasma tyrosine concentration. The decrease in plasma amino acids caused by these catecholamines is inhibited by propranolol, suggesting that this effect is mediated via adrenergic β-receptors, while the increasing effect is inhibited by phenoxybenzamine, which suggests that this effect is caused by an α-adrenergic mechanism.     

Compensation of DNA stabilization and destabilization effects caused by cisplatin is partially disturbed in alkaline medium

Binding of the antitumor compound cisplatin to DNA locally distorts the double helix. These distortions correlate with a decrease in DNA melting temperature (Tm). However, the influence of cisplatin on DNA stability is more complex because it decreases the DNA charge density. In this way, cisplatin increases the melting temperature and partially compensates for the destabilizing influence of structural distortions. The stabilization is stronger at low Na+ ion concentration. Due to this compensation, the total decrease in the DNA melting temperature after cisplatin binding is much lower than the decrease caused by the distortions themselves, especially at low [Na+]. It is shown in this study that, besides Na+ concentration, pH also strongly influences the value of a change in the melting temperature caused by cisplatin. In alkaline medium (pH=10.5-10.8), a fall in the melting temperature caused by platination is enhanced several times with respect to neutral medium. Such a stronger drop in Tm is explained by a decrease in pK values of base pairs caused by lowering the charge density under platination that facilitates proton release. At neutral pH, the proton release is low for both control and platinated DNA and does not influence the melting behavior. Therefore, lowering in the charge density under platination, besides stabilization, gives additional destabilization just in alkaline medium. Destabilization caused by structural distortions due to this pH induced compensation of stabilizing effect is more pronounced. In the presence of carbonate ion, destabilization caused by high pH value is strengthened. As a decrease in DNA charge density, interstrand crosslinking caused by cisplatin also increases the DNA stability due to loss in the entropy of the melted state. However, computer modeling of DNA stability demonstrates that interstrand crosslinks formed by cisplatin do not stabilize long DNA. It is shown that the increase in Tm caused by interstrand crosslinking itself is compensated for by a local destabilization of the double helix at the sites of location of interstrand crosslinks formed by cisplatin.     

Onychomycosis by <Emphasis Type="Italic">Scytalidium dimidiatum</Emphasis> in green tea leaf pluckers: report of two cases

Two cases of onychomycosis in green tea leaf pluckers caused by Scytalidium dimidiatum, a dematiaceous non-dermatophytic mold has been desribed. Onychomycosis caused by Scytalidium dimidiatum is clinically indistinguishable from that caused by dermatophytes and responds poorly to antifungals. The clinical presentations in the cases were of distal subungual type with associated melanonychia involving thumbnails. These cases have unique importance, because besides disfigurement, this has adversely affected the livelihood of the patient and poor response to antifungal dissuaded them from treatment compliance. To the best of our knowledge, this is the first report of onychomycosis caused by Scytalidium dimidiatum in green tea leaf pluckers.     

Specific antibody response in a patient with Candida dubliniensis fungemia

We report a case of fungemia caused by Candida dubliniensis in a non-HIV infected patient. Multiple cultures of blood performed over a period of 13 days were positive for this recently described yeast species. The C. dubliniensis isolates recovered were susceptible to fluconazole in vitro and the patient responded to intravenous therapy with this antifungal agent. It was possible to differentiate the fungemia caused by C. dubliniensis in this patient from that caused by C. albicans in other patients on the basis of the analysis of the antibody response since the C. dubliniensis-infected patient exhibited a characteristic and specific antibody response against a cell wall component of 160-170 kDa.     

First Isolation of Pseudogymnoascus destructans,the Fungal Causative Agent of White-Nose Disease,in Bats from Italy

Mycopathologia - White-nose disease, caused by the dermatophyte Pseudogymnoascus destructans, is a devastating pathology that has caused a massive decline in the US bat populations. In Europe, this...     

Control of ethanol utilization by rat hepatocytes

Ethanol oxidation by hepatocytes from fasted rats was determined in the presence and absence of 0.2 mM ethyl hyrazinoacetate, a transaminase inhibitor which blockes the malate-aspartate cycle. 20 μM phenazine methosulfate caused the larges increase (nearly 150%) in ethanol utilization. 5 μM norepinephrine caused a 50% increase in ethanol oxidation, and most fo this increase was caused by stimulation of the α-glycerophosphate shuttle, since it remained in the presence of ethyl hydrazinoacetate. 1 μM glucagon caused a 25% increase in ethanol uptake, and most of this increase was abolished by ethyl hydrazinoacetate, indicating that the malate-aspartate cycle was involved. 25 μM dinitrophenol increased ethanol use by 20% and this increase was nearly unaffected by ethyl hydrazinoacetate. The results indicate that ethanol utilization, under the conditionsused, is primarily controlled by the capacity of the shuttle systems, and not by the capacity of teh respiratory chain.     

一种引致人体原发性皮肤毛霉病的非高温根毛霉属真菌

由石家庄中国人民解放军白求恩国际和平医院皮肤科李成龙大夫提供的一株人体皮肤病菌经我们研究鉴定为毛霉目(Mucorales)毛霉科(Mucoraceae)根毛霉属(Rhizomucor)的一个种,并定名为多变根毛霉新种(Rhizomucor variabilis Zheng & G.-q.Chen sp. nov.)。据李大夫介绍,这株菌是从一名居住在江苏农村到该医院看病的女病人的手上病部分离的。这个病人没有一般真菌病病人所患有的其他疾病如糖尿病、白血病等等。她也没有患有其他毛霉病,因此她的皮肤毛霉病是原发性的而不是继发性的。我们查阅文献结果,国内由根毛霉属真菌引致的毛霉病过去仅有过一次肺部感染的报道;国外则有过较多次数的由根毛霉引致的人体毛霉病,主要为肺部疾病并可引致继发性的皮肤病,尚未见有由根毛霉属引起的原发性皮肤毛霉病的报道。无论国内、外引起人体毛霉病的根毛霉均为微小根毛霉[Rhizomucor pusillus(Lindt) Schipper,包括Mucor pusillus Lindt,Mucor parasiticus Lucet & Costanin等异名]一种。因此,本病例为我国第二例由根毛霉弓l起的人体毛霉病及第一例由根毛霉引起的人体皮肤毛霉病,同时又是全世界第一例由根毛霉属除微小根毛霉以外的另外一个种引起的人体毛霉病,很可能还是全世界第一例由根毛霉引起的人体原发性皮肤毛霉病。多变根毛霉与根毛霉属内所有过去已报道过的种都有显著差异。它的最适生长温度为24-30℃,最低9℃,最高38℃;其他种均为高温真菌,它们的最高生长温度可达55℃或更高。形态方面,多变根毛霉也与属内其他已知种明显不同。它的菌落高达4-8 mm并呈鲜明的浅黄色;其他已知种菌落低矮,除奈尼塔尔根毛霉(Rhizomucor nainitalensis Joshi)外全部为深暗灰色,奈尼塔尔根毛霉菌落色泽虽然较浅,但为浅灰或灰黄色,与多变根毛霉的鲜明黄色不同。它的假根异常发达并可从菌体的各个部位如菌丝、匍匐丝、孢子枝、孢子囊、囊轴上长出;其他已知种的假根一般都不发达且从未见有从孢子枝、孢子囊、囊轴等处长出的描述。它的孢子枝的分枝常常长于主枝;其他已知种则分枝长度一般不超过主枝。它的囊轴形状多变:球形、近球形、扁球形、卵形、椭圆形、梨形等等,两边对称或不对称,溢缩或不绕缩,纵向深裂或不作纵向深裂;其他已知种的囊轴形状通常为倒卵形至梨形的规则形状。它的囊领明显;其他已知种的囊领均很不明显至缺如。它的孢囊孢子形状和大小变化都较大,卵形、椭圆形、矩圆形、近球形、近三角形或其他各种不规则形状,长度范围2.5-16.5 μm;其他已知种除上面已经提到过的奈尼塔尔根毛霉外,它们的孢囊孢子形状仅限于卵形、椭圆形、近球形等较规则的形状,长度范围总是在3-6 μm范围内,奈尼塔尔根毛霉的孢囊孢子形状虽然多变,但其决度亦在3-6 μm的范围内。此外,多变根毛霉的孢子囊、囊轴、孢囊孢子等各种构造均较大;其他已知种则较小,其中肿梗根毛霉[Rhizomucor tauricus (Milko & Schkurenko) Schipper]虽亦较大,但除此之外与多变根毛霉迥异。多变根毛霉未见有接合孢子,将我们保存的全部微小根毛霉菌株与它分别配对时,或将我们的几对别的属的(+)(-)测试菌株与它分别配对时,均未见形成接合孢子或有任何反应。     

Inhibitory action of auxin on root elongation not mediated by ethylene

The inhibitory effects of indole-3-acetic acid (IAA) and 1-aminocyclopropane-1-carboxylic acid (ACC) on elongation growth of pea (Pisum sativum L.) seedling roots were investigated in relation to the effects of these compounds on ethylene production by the root tips. When added to the growth solution both compounds caused a progressively increasing inhibition of growth within the concentration range of 0.01 to 1 micromolar. However, only ACC increased ethylene production in root tips excised from the treated seedlings after 24 hours. High auxin concentrations caused a transitory increase of ethylene production during a few hours in the beginning of the treatment period, but even in 1 micromolar IAA this increase was too low to have any appreciable effect on growth. ACC, but not IAA, caused growth curvatures, typical of ethylene treatment, in the root tips. IAA caused conspicuous swelling of the root tips while ACC did not. Cobalt and silver ions reversed the growth inhibitory effects induced by ACC but did not counteract the inhibition of elongation or swelling caused by IAA. The growth effects caused by the ACC treatments were obviously due to ethylene production. We found no evidence to indicate that the growth inhibition or swelling caused by IAA is mediated by ethylene. It is concluded that the inhibitory action of IAA on root growth is caused by this auxin per se.     

Superoxide dismutase inhibits the superoxide-driven Fenton reaction at two different levels. Implications for a wider protective role

Superoxide dismutase (SOD) completely inhibits the damage caused by a ferric-EDTA chelate in the presence of a superoxide-generating system. In this reaction superoxide is enzymically dismuted to hydrogen peroxide. Since hydrogen peroxide and a ferric-EDTA chelate are themselves a hydroxyl radical-generating system, it follows that SOD must also protect against damage done by this reaction. The ability of SOD to inhibit damage to deoxyribose caused by hydrogen peroxide and a ferric-EDTA chelate is experimentally demonstrated in this paper.     

Clinical and epidemiological aspects of various forms of fungal infections caused by Trichophyton tonsurans

In the years 1977-1996 103 cases of mycosis caused by Trichophyton tonsurans with lesions in a variety of locations were treated. T. tonsurans was most often cultured from the feet (61.2%), and toe nails (22.3%), although smaller quantities were also obtained from other locations. In 1990, an endemic focus of superficial ringworm of the hairless skin caused by T. tonsurans was observed in 23 village children. The endemic focus of trichophytos is caused by this dermatophyte gives evidence of a high infectious potential of this species. In favourable circumstances the dermatophyte can cause massive fungal infections also in our geographic region.     

Clostridium symbiosum as a cause of bloodstream infection in an immunocompetent patient

Bloodstream infection caused by Clostridium symbiosum was previously reported in only one case, from a highly immunocompromised patient with metastic colon cancer. We describe the second case of clinical bacteraemic sepsis caused by C. symbiosum from a previously healthy man, which underlines the pathogenicity of this species.     

Cell Damage Associated with Changing the Medium of Mesencephalic Cultures in Serum-Free Medium Is Mediated via N-Methyl-D-Aspartate Receptors

Dopaminergic neurons from embryonic rat mesencephalon were grown in simple serum-free media. The cells develop over a period of several weeks in vitro, particularly between day 14 and day 23. Removing the culture medium and replacing it with fresh medium during this interval caused severe damage to the cultures; this damage is mediated by excitatory amino acids acting through glutamate receptors. Damage could be completely prevented by antagonists of the N-methyl-D-aspartate subtype of glutamate receptor. As expected, medium that contains glutamate (i.e., Ham's F-12 medium) caused damage; however, medium that contains no glutamate or aspartate (i.e., Dulbecco's modified Eagle medium) also caused severe damage, and most of the damage was dependent on the presence of glutamine in the medium. The presence of the antibiotics penicillin and streptomycin greatly enhanced damage caused by medium change.     

Okadaic acid inhibits angiotensin II, adrenocorticotropin and potassium-dependent aldosterone secretion

The present study was designed to assess the effect of okadaic acid (OA), a protein phosphatase inhibitor, on aldosterone secretion in response to angiotensin II (AII), adrenocorticotropin (ACTH) and rises in external potassium concentration (K+). AII (10nM) caused a 20-fold increase in aldosterone production and OA reduced this response by 45%. ACTH (10nM) caused an 8.6-fold increase in aldosterone secretion and OA reduced this by 83%. Increasing K+ concentration from 3 to 12mM caused a 13-fold increase in aldosterone production, which OA inhibited by 36%. These results suggest that protein phosphatases participate in the control of adrenal steroid production, even though ACTH, AII and K+ act via different intracellular messenger systems.     

Isolation and characterization of ftsZ alleles that affect septal morphology.

The ftsZ gene encodes an essential cell division protein that specifically localizes to the septum of dividing cells. In this study we characterized the effects of the ftsZ2(Rsa) mutation on cell physiology. We found that this mutation caused an altered cell morphology that included minicell formation and an increased average cell length. In addition, this mutation caused a temperature-dependent effect on cell lysis. During this investigation we fortuitously isolated a novel temperature-sensitive ftsZ mutation that consisted of a 6-codon insertion near the 5' end of the gene. This mutation, designated ftsZ26(Ts), caused an altered polar morphology at the permissive temperature and blocked cell division at the nonpermissive temperature. The altered polar morphology resulted from cell division and correlated with an altered geometry of the FtsZ ring. An intragenic cold-sensitive suppressor of ftsZ26(Ts) that caused cell lysis at the nonpermissive temperature was isolated. These results support the hypothesis that the FtsZ ring determines the division site and interacts with the septal biosynthetic machinery.     

Toxic effects of fatty acid anilides on the oxygen defense systems of guinea pig lungs and erythrocytes

Toxic oil syndrome (TOS) is caused by ingestion of denatured edible oils. Even though the etiology and pathogenesis of this disease are not fully known, it is quite clear that generation of free radicals caused by ingestion of fatty acid anilides is responsible for the pathogenetic mechanism in many TOS patients. Fatty acid anilides may also alter the free radical status of lungs and erythrocytes; this possibility may shed some light on understanding toxic oil syndrome. The present study describes the effects of oral administration of fatty acid anilides on the activities of major enzymes involved in the oxygen defense systems of lungs and erythrocytes. Feeding fatty acid anilides caused an increase in the superoxide dismutase (SOD) activity in erythrocytes, whereas it caused a decrease in the SOD activity in lungs. GSH-Px activity was not significantly changed in erythrocytes but was decreased in lungs. Although the activity of catalase was increased only by a higher dose in the erythrocytes, it was not affected in the lung at any dosage. Even though the ingestion of fatty acid anilides caused an increase in the SOD activity in the erythrocytes and a decrease in the SOD activity in the lungs, there was an increase in the lipid peroxidation in both cases. The increase in lipid peroxidation in erythrocytes is probably caused by the accumulation of H₂O₂, and that in the lungs is due to the accumulation of superoxide anion.     

Paradoxical effect of salbutamol in a model of acute organophosphates intoxication in guinea pigs: role of substance P release

Organophosphates induce bronchoobstruction in guinea pigs, and salbutamol only transiently reverses this effect, suggesting that it triggers additional obstructive mechanisms. To further explore this phenomenon, in vivo (barometric plethysmography) and in vitro (organ baths, including ACh and substance P concentration measurement by HPLC and immunoassay, respectively; intracellular Ca2+) measurement in single myocytes) experiments were performed. In in vivo experiments, parathion caused a progressive bronchoobstruction until a plateau was reached. Administration of salbutamol during this plateau decreased bronchoobstruction up to 22% in the first 5 min, but thereafter airway obstruction rose again as to reach the same intensity as before salbutamol. Aminophylline caused a sustained decrement (71%) of the parathion-induced bronchoobstruction. In in vitro studies, paraoxon produced a sustained contraction of tracheal rings, which was fully blocked by atropine but not by TTX, omega-conotoxin (CTX), or epithelium removal. During the paraoxon-induced contraction, salbutamol caused a temporary relaxation of approximately 50%, followed by a partial recontraction. This paradoxical recontraction was avoided by the M2- or neurokinin-1 (NK1)-receptor antagonists (methoctramine or AF-DX 116, and L-732138, respectively), accompanied by a long-lasting relaxation. Forskolin caused full relaxation of the paraoxon response. Substance P and, to a lesser extent, ACh released from tracheal rings during 60-min incubation with paraoxon or physostigmine, respectively, were significantly increased when salbutamol was administered in the second half of this period. In myocytes, paraoxon did not produce any change in the intracellular Ca2+ basal levels. Our results suggested that: 1) organophosphates caused smooth muscle contraction by accumulation of ACh released through a TTX- and CTX-resistant mechanism; 2) during such contraction, salbutamol relaxation is functionally antagonized by the stimulation of M2 receptors; and 3) after this transient salbutamol-induced relaxation, a paradoxical contraction ensues due to the subsequent release of substance P.     

THE PHOTOINHIBITION OF GROWTH IN ETIOLATED STEM SEGMENTS. II. GROWTH CAUSED BY COBALT IN PISUM

Bertsch, Walter F. (Yale U., New Haven, Conn.) The photoinhibition of growth in etiolated stem segments. II. Growth caused by cobalt in Pisum. Amer. Jour. Bot. 50(3): 213–219. Illus. 1963.—Etiolated pea stem sections were utilized to study the effects of various metal ions on the red, far-red photoinhibition of stem growth. Excision of immature tissue results in loss of photosensitivity. All growth caused by cobalt, either in the presence or absence of sugar, was inhibited by brief exposure of the excised tissue to red light. Since growth caused by sugar is also light-sensitive, it may be said that either cobalt or sugar may induce photosensitivity in this immature tissue. Other divalent metal ions were tested, but only nickel promoted growth. Although cobalt and nickel showed the same optimal concentration (ca. 2 × 10⁻⁵ m), growth caused by nickel was not photosensitive, suggesting that cobalt and nickel promoted growth through separate mechanisms. Since growth caused by indole-3-acetic acid or gibberellic acid is also insensitive to light in this tissue, a photosensitive sugar-cobalt growth system has been experimentally separated from other growth-controlling systems. The photoinhibition of a growth system which utilizes sugars and is promoted by cobalt and the relation of this system to certain de-etiolation phenomena are discussed.     

Desensitization of ornithine decarboxylase activity to norepinephrine in the testis of rat

Injection of norepinephrine (NE) at a dose of 10 micrograms per testis caused the testis refractory in terms of ornithine decarboxylase (ODC) activity at 24 h. This desensitization was found to be both time and dose dependent. Injection with follicle stimulating hormone, luteinizing hormone, prostaglandin F2 alpha, cyclic AMP or epinephrine to norepinephrine desensitized testis caused stimulation of ODC activity. This indicates that the refractoriness caused by norepinephrine is specific to this agent alone.     

Action of cholera toxin on dispersed acini from rat pancreas. Post-receptor modulation involving cyclic AMP and calcium

In dispersed acini from rat pancreas, cholera toxin caused a significant increase in cellular cyclic AMP but little or no change in amylase secretion. The presence of a secretagogue that causes mobilization of cellular calcium (e.g., cholecystokinin, carbamylcholine, bombesin or ionophore A23187) caused a substantial increase in the effect of cholera toxin on enzyme secretion. Cholera toxin did not alter calcium transport or the changes in calcium transport caused by other secretagogues, and secretagogues that mobilize cellular calcium did not alter cellular cyclic AMP or the increase in cyclic AMP caused by cholera toxin. These results indicate that in dispersed acini from rat pancreas there is post-receptor modulation of the action of cholera toxin by secretagogues that mobilize cellular calcium and that this modulation is a major determinant of the effect of the toxin on enzyme secretion.     

复杂易位遗传效应的探讨—附一例罕见复杂易位核型

本报道一例罕见复杂易位核型：46,XX,t(1;14;10)。并到往资料,探讨和分析复杂易位和一般平衡易位对表型及生育的遗传效应。结果显示,一般易位导致智能低下和多发畸形的频率各为3.57%,复杂易位所致智能低下频率为21.73%, 多发畸形的频率为17.39%。提示复杂2易位所致智能低下和畸形频率明显高于一般易位。