Fluorescence intermittency in self-assembled InP quantum dots

Fluorescence intermittency in InP self-assembled dots is investigated by means of far field imaging and single dot spectroscopy. Based on our observation that blinking dots are found in the vicinity of scratches and the blinking frequency is drastically enhanced under a near-infrared laser irradiation, we attribute the origin of the fluorescence intermittency to a local electric field due to a carrier trapped at a deep localized center in the Ga0.5In0.5P matrix. The validity of this explanation is confirmed by a thermal activation-type behavior of the switching rate and artificial reproduction of the blinking phenomenon by an external electric field.

Carotid endarterectomy with external shunt: a new device and indication for use: technical note

OBJECTIVE

We designed a new external shunt system and evaluated its indications and efficacy in patients undergoing carotid endarterectomy (CEA).

METHODS

In 8 of 332 CEA procedures, external shunts were placed between the common carotid artery and the internal carotid artery (ICA). This procedure was implemented for one of two indications: 1) a change in electroencephalographic and/or somatosensory evoked potential readings immediately after ICA occlusion, or 2) elongation of the ICA made safe insertion of an internal shunt impossible. In addition, a shunt was placed between the common carotid artery and the external carotid artery to establish collateral circulation from the external carotid artery to the intracranial circulation, which is essential during ICA occlusion.

RESULTS

All external shunts were functional, and electroencephalography and somatosensory evoked potentials demonstrated no significant abnormalities during the CEAs. All patients awoke from surgery without manifestation of new neurological deficits.

CONCLUSION

Our new external shunt device proved safe and efficacious in cases that did not permit the placement of an internal shunt.

Effect of round-edged acrylic intraocular lenses on preventing posterior capsule opacification

PURPOSE

To clarify the extent to which the adhesiveness of an acrylic material influences the formation of posterior capsule opacification (PCO).

SETTING

Jinshikai Medical Foundation, Nishi Eye Hospital, Osaka, Japan.

METHODS

Two types of AcrySof(R) intraocular lenses (IOLs) were prepared: round edged and tumbled. The AcrySof with round edges was implanted in 1 eye in a group of 4 rabbits and the tumbled IOL, in 1 eye in a group of 5 rabbits. In both groups, the contralateral eye received a conventional AcrySof with sharp optic edges. A histopathological examination was performed 3 weeks after surgery.

RESULTS

With the round-edged AcrySof IOL, no capsular bend formed at the optic edge and abundant lens epithelial cells (LECs) migrated posteriorly. With the sharp-edged AcrySof lens, a sharp capsular bend formed and LEC migration was significantly inhibited. In eyes with a tumbled IOL, a capsular bend was created, but it was less marked than that created by the sharp-edged lens and there was slightly more LEC migration posteriorly.

CONCLUSIONS

The AcrySof IOL lost its preventive effect on PCO when the optic was rounded. The effect of the AcrySof lens in preventing PCO is mainly a result of its rectangular, sharp-edged optic design. The acrylic material may play a complementary role by helping create a sharp capsular bend. Capsular bend formation is the key to the PCO preventive effect of an IOL.

Near-field spectroscopy of single quantum dots at room temperature

The observation of photoluminescence spectra of self-assembled single InGaAs quantum dots at room temperature was performed under weak excitation conditions using a near-field scanning optical microscope. Operation in illumination-collection mode with a highly sensitive double-tapered optical fibre probe enabled detection of weak photoluminescence signals at room temperature with high efficiency and high spatial resolution. Each single quantum dot was imaged with a spatial resolution of about 250 nm, which corresponded to a quarter of the wavelength of the photoluminescence from quantum dots. The photoluminescence yields of individual quantum dots were widely distributed and were found to decrease with photoluminescence energy. This result serves as a clue to be pursued for better understanding of the thermal excitation of the carrier from confined states in quantum dots.

Effects of consonantal context on perceptual assimilation of American English vowels by Japanese listeners

This study investigated the extent to which adult Japanese listeners' perceived phonetic similarity of American English (AE) and Japanese (J) vowels varied with consonantal context. Four AE speakers produced multiple instances of the 11 AE vowels in six syllabic contexts /b-b, b-p, d-d, d-t, g-g, g-k/ embedded in a short carrier sentence. Twenty-four native speakers of Japanese were asked to categorize each vowel utterance as most similar to one of 18 Japanese categories [five one-mora vowels, five two-mora vowels, plus/ei, ou/ and one-mora and two-mora vowels in palatalized consonant CV syllables, C(j)a(a), C(j)u(u), C(j)o(o)]. They then rated the "category goodness" of the AE vowel to the selected Japanese category on a seven-point scale. None of the 11 AE vowels was assimilated unanimously to a single J response category in all context/speaker conditions; consistency in selecting a single response category ranged from 77% for /eI/ to only 32% for /ae/. Median ratings of category goodness for modal response categories were somewhat restricted overall, ranging from 5 to 3. Results indicated that temporal assimilation patterns (judged similarity to one-mora versus two-mora Japanese categories) differed as a function of the voicing of the final consonant, especially for the AE vowels, /see text/. Patterns of spectral assimilation (judged similarity to the five J vowel qualities) of /see text/ also varied systematically with consonantal context and speakers. On the basis of these results, it was predicted that relative difficulty in the identification and discrimination of AE vowels by Japanese speakers would vary significantly as a function of the contexts in which they were produced and presented.

Selective expression of erg isoforms in human endothelial cells

Erg and Fli-1 are closely related members of the ets family of transcription factors. There are at least five human Erg isoforms (Erg-1, Erg-2, Erg-3/p55(Erg), p49(Erg) and p38(Erg)) produced through differential mRNA splicing and alternative use of translational start codons. However, relatively little is known about the expression or function of these isoforms in vitro or their distribution in vivo. We used RT-PCR to screen a panel of primary and established human cell lines for erg and fli-1 consensus sequences. Whilst fli-1 was expressed in several human cell types, erg was detected mainly in endothelial cells. To identify which erg isoforms are expressed in endothelial cells we used RT-PCR, Northern blotting and 5'-RACE. Erg-3/p55(Erg) and p38(Erg)/p38(Erg)-like transcripts were detected in both microvascular and large vessel endothelial cells affinity-purified from different vascular beds. Moreover, these erg isoforms were present in both freshly isolated, and confluent endothelial cells following several passages in culture, indicating that endothelial erg expression in vitro may be broadly representative of that in vivo. The selective expression of the Erg-3/p55(Erg) and p38(Erg)/p38(Erg)-like isoforms in endothelial cells indicates their involvement in the regulation of endothelial-restricted genes.

Mutation of an arginine biosynthesis gene causes reduced pathogenicity in Fusarium oxysporum f. sp. melonis

Restriction enzyme-mediated integration (REMI) mutagenesis was used to tag genes required for pathogenicity of Fusarium oxysporum f. sp. melonis. Of the 1,129 REMI transformants tested, 13 showed reduced pathogenicity on susceptible melon cultivars. One of the mutants, FMMP95-1, was an arginine auxotroph. Structural analysis of the tagged site in FMMP95-1 identified a gene, designated ARG1, which possibly encodes argininosuccinate lyase, catalyzing the last step for arginine biosynthesis. Complementation of FMMP95-1 with the ARG1 gene caused a recovery in pathogenicity, indicating that arginine auxotrophic mutation causes reduced pathogenicity in this pathogen.

Development of haemoglobin subtypes and extramedullary haematopoiesis in young rats. Effects of hypercapnic and hypoxic environment

The influence of repeated hypoxia on the development of haemoglobin (Hb) subtypes and on extramedullary haematopoiesis (EMH) was investigated in young Wistar rats of different ages. The rats were exposed to hypercapnic/hypoxic and to "simple" hypoxic conditions. The results obtained were compared to those of an untreated age-matched control group. Different globin chains were measured using HPLC and time-of-flight (TOF) mass analysis. The number of EMH cells was evaluated by cell counting. By determining the proportions of alpha- and beta-chains, fetal, neonatal and mature types of globin chain composition could be differentiated. The beta-2 chain levels were significantly higher in hypercapnic/hypoxic environments than in the controls and simple hypoxic environments. The numbers of EMH cells in the two groups subjected to hypercapnia/hypoxia decreased significantly more slowly compared to the controls and simple hypoxia groups. Therefore, the development of Hb subtypes and the EMH activity in rats were influenced by both repeated hypercapnia and hypoxia.

Pyrrolidine inhibitors of human cytosolic phospholipase A2. Part 2: synthesis of potent and crystallized 4-triphenylmethylthio derivative 'pyrrophenone'

We synthesized a potent and crystallized human cytosolic phospholipase A2alpha inhibitor, pyrrophenone (6) which inhibits the isolated enzyme with an IC50 value of 4.2 nM. Pyrrophenone shows potent inhibition of arachidonic acid release, prostaglandin E2, thromboxane B2, and leukotriene B4 formation in human whole blood. The magnitudes of prostaglandin E2 and thromboxane B2 inhibition are the same as those of indomethacin.

Functional annotation of a full-length mouse cDNA collection

The RIKEN Mouse Gene Encyclopaedia Project, a systematic approach to determining the full coding potential of the mouse genome, involves collection and sequencing of full-length complementary DNAs and physical mapping of the corresponding genes to the mouse genome. We organized an international functional annotation meeting (FANTOM) to annotate the first 21,076 cDNAs to be analysed in this project. Here we describe the first RIKEN clone collection, which is one of the largest described for any organism. Analysis of these cDNAs extends known gene families and identifies new ones.

Purification, molecular cloning, and immunohistochemical localization of dipeptidyl peptidase II from the rat kidney and its identity with quiescent cell proline dipeptidase

We purified dipeptidyl peptidase II (DPP II) to homogeneity from rat kidney and determined its physicochemical properties, including its molecular weight, substrate specificity, and partial amino acid sequence. Furthermore, we screened a rat kidney cDNA library, isolated the DPP II cDNA and determined its structure. The cDNA was composed of 1,720 base pairs of nucleotides, and 500 amino acid residues were predicted from the coding region of cDNA. Human quiescent cell proline dipeptidase (QPP) cloned from T-cells is a 58-kDa glycoprotein existing as a homodimer formed with a leucine zipper motif. The levels of amino acid homology were 92.8% (rat DPP II vs. mouse QPP) and 78.9% (rat DPP II vs. human QPP), while those of nucleotide homology were 93.5% (rat DPP II vs. mouse QPP) and 79.4% (rat DPP II vs. human QPP). The predicted amino acid sequences of rat DPP II and human and mouse QPP possess eight cysteine residues and a leucine zipper motif at the same positions. The purified DPP II showed similar substrate specificity and optimal pH to those of QPP. Consequently, it was thought that DPP II is identical to QPP. Northern blot analysis with rat DPP II cDNA revealed prominent expression of DPP II mRNA in the kidney, and the order for expression was kidney >> testis > or = heart > brain > or = lung > spleen > skeletal muscle > or = liver. In parallel with Northern blot analysis, the DPP II antigen was detected by immunohistochemical staining in the cytosol of epithelial cells in the kidney, testis, uterus, and cerebrum.

Enhancement of intracellular Cl- concentrations induced by extracellular ATP in guinea pig ventricular muscle

We investigated effects of extracellular ATP on intracellular chloride activities ([Cl-]i) and possible contribution of the Cl--HCO3- exchange to this increase in [Cl-]i in isolated guinea pig ventricular muscles. The [Cl-]i and intracellular pH (pHi) were recorded in quiescent ventricular muscles using double-barreled ion-selective microelectrode techniques. MgATP at a concentration higher than 0.1 mM, induced an increase in [Cl-]i, and this increase in [Cl-]i was dependent on the concentration of ATP but not on the concentration of magnesium ions present in the perfusion solution. NaADP, but not NaAMP, at a concentration of 0.5 mM induced a similar increase in [Cl-]i as that induced by MgATP. However, the NaADP-induced increase in [Cl-]i was transient and gradually returned to the control level even though NaADP was continuously present. Furthermore, ATP also triggered a transient acidification of pHi, and both increases in [Cl-]i and intracellular H+ induced by ATP were prevented when preparations were pretreated with stilbene derivatives, SITS and DIDS, or perfused with a Cl--free solution. Our findings showed that the increased extracellular ATP concentrations might trigger an increase in [Cl-]i in ventricular muscles. In light of previous studies showing that cardiac ischemia induced increases in extracellular nucleotide concentrations and [Cl-]i in ventricular muscles, we propose that ischemia-induced accumulation of ATP concentration in the extracellular space may be an important factor to trigger increment of [Cl-]i during ischemic conditions.

[Survey on postmortem examination to police surgeons and emergency physicians. Possibility of physicians' assist in mass-disaster]

We conducted a questionnaire survey of police surgeons and emergency physicians, inquiring about their experience of medicolegal investigation of death and their willingness to join a death investigation team in a major disaster. The questionnaire also asked about their knowledge about and interest in the forensic specialist system established by the Japanese Society of Legal Medicine. Police surgeons were generally willing to join an investigation team only if a disaster occurred in or close to their hometown, because they could not afford more than several days away from patient care. Although many of the emergency physicians were willing to join a death investigation team, they had difficulty in doing so without permission or orders from their employer or the authorities concerned. The survey found that the percentage of aged police surgeons was increasing among those surveyed. This fact, in combination with the current emphasis of postgraduate education on specialty training, threatens to cause a substantial lack of physicians available for medicolegal investigation of death. Therefore, it is urgently necessary to establish a system of training resident and emergency physicians in medicolegal investigation of death. In addition to providing postgraduate training in medicolegal investigation of death to prospective trainees who are emergency physicians at major hospitals in potential disaster-stricken areas, the medical school should incorporate forensic medicine in postgraduate training programs so that they can actively perform death investigation on disaster victims dying before or after arrival at their hospitals. Furthermore, the forensic community should make every effort to increase the number of autopsies in each department of forensic medicine and to expand the medical examiner system throughout Japan that is currently in practice only in the Metropolis of Tokyo and Yokohama, Nagoya, Osaka and Kobe Cities in order to incorporate forensic training in the postgraduate clinical training programs that will become compulsory in 2004.

[Pharmacokinetics of cisplatin and methotrexate in a patient suffering from advanced ureteral tumor accompanied by chronic renal failure, undergoing combined hemodialysis and systemic M-VAC chemotherapy]

The pharmacokinetics of cisplatin and methotrexate were determined in a patient suffering from advanced ureteral tumor accompanied by chronic renal failure undergoing 4 consecutive cycles of M-VAC chemotherapy and hemodialysis. No significant difference was observed in t1/2, AUC or CLtot of total platinum between the patient with the chronic renal failure and patients with normal renal function. The AUC and CLtot of free platinum in the patient with the chronic renal failure were higher and lower, respectively, than in the patients with normal renal function. The free cisplatin rebounded remarkably after the end of dialysis, which may be partly attributed to an increase in the AUC and decrease in CLtot. However, the dialysis index was about 75 and 85% in the 3rd and 4th cycles, respectively. The t1/2 and CLtot of methotrexate in the patient with the chronic renal failure tended to be longer and smaller than those in patients with normal renal function, respectively. Seventy-two hours after administration, the methotrexate level was 0.02 microM, which was not at the high-risk level of high-dose therapy. After four cycles of M-VAC therapy, the rest of the right ureteral tumor was extirpated and the clinical response was CR. In conclusion, it is considered that cisplatin and methotrexate can be given to a patient with chronic renal failure. However, the cisplatin and methotrexate serum levels must be monitored, even after very low doses.

The carbohydrate deposits detected by histochemical methods in the molecular layer of the dentate gyrus in the hippocampal formation of patients with schizophrenia, Down's syndrome and dementia, and aged person

Post-mortem brain tissue was obtained from 28 patients with brain disorders, of which 15 had clinically diagnosed schizophrenia, 6 Alzheimer type dementia, 5 dementia with tangles and 2 cases of Down's syndrome. The controls were 22 cases from autopsies without brain disorders or with no known episodes of brain disorder. The tissues were stained for the detection of carbohydrate deposits in the hippocampal formation, using lectin, immunohistochemical and conventional staining methods. The staining revealed the existence of spherical deposits in the inner and middle molecular layers of the dentate gyrus in the hippocampal formation which contained fucose, galactose, N-acetyl galactosamine, N-acetyl glucosamine, sialic acid, mannose and chondroitin sulfate. The number of the deposits was higher in patients with brain disorder such as schizophrenia, Alzheimer type dementia, dementia with tangles or Down's syndrome, and in some aged individuals, in comparison to those in younger individuals. No deposits were detected in a few younger or aged individuals. Spherical deposits 3-10 microm in diameter may be an immature form of the corpora amylacea, since they were similar in the histochemical characteristics with lectin, immunohistochemical and conventional staining methods. However, differing staining ability by hematoxylin, periodic acid Schiff's reagent and antibodies against the intracellular degraded proteins such as ubiquitin and tau-protein was observed. The antibodies against ubiquitin and tau-protein showed clear reactivity with the corpora amylacea and no reactivity with spherical deposits, indicating that the corpora amylacea has an intracellular origin and spherical deposits an extracellular matrix origin. The results obtained in this study indicate that not only neuronal degeneration but also unusual glycometabolism in neurons may disturb the neuronal function and cause brain disorders, and that spherical deposits may cause dysfunction of the neuronal network in the dentate gyrus of the hippocampus which is closely linked with recognition and memory functions.

[Significance of product documents (tenpubunsho) cited in judicial precedents in the field of anesthesiology]

The significance of the product documents (Tempubunsho) was mentioned in 21 out of 94 medical malpractice cases published in several laws reports 1963-97. The number of such cases has been increasing in recent years. Among the items described in the product documents, the precautions for use were most frequently mentioned (12 cases) followed by the instructions for administration and dosage (3 cases). In most cases, the judgment was against the medical institution involved due to the violation of legal obligations with respect to the contents of the product documents. Product documents will be taken much more seriously in future lawsuits. Attention should be focused on the contents of the product documents, especially when revised. When the administration of a drug deviates from the contents of the product document, medical evidence is required to support this deviation.

Preventing lens epithelial cell migration using intraocular lenses with sharp rectangular edges

PURPOSE

To compare the preventive effect on posterior capsule opacification (PCO) of an acrylic intraocular lens (IOL) and a silicone IOL, both with sharp rectangular optic edges.

SETTING

Jinshikai Medical Foundation, Nishi Eye Hospital, Osaka, Japan.

METHODS

After phacoemulsification, an acrylic IOL (AcrySof(R)) was implanted in 1 eye and a silicone IOL (CeeOn 911) in the contralateral eye of 7 rabbits, one of which was omitted from evaluation.

RESULTS

The Miyake-Apple view and histopathological findings 3 weeks after surgery revealed that the lens capsule wrapped tightly around the optic edges, conforming to a distinctly sharp bend, with both IOL types in 5 rabbits. Migrating lens epithelial cells (LECs) were inhibited at the site. The AcrySof IOL had a better capsular bend effect in the histological sections, but there was no apparent difference in PCO development between the 2 IOLs.

CONCLUSIONS

The CeeOn 911 silicone IOL, with sharp rectangular optic edges, showed an effect on preventing PCO that was similar to that of the AcrySof IOL. When a discontinuous capsular bend is created by an IOL with sharp optic edges, the bend may induce contact inhibition of migrating LECs regardless of the lens' material composition.

Puromycin-sensitive alanyl aminopeptidase from human liver cytosol: purification and characterization

A cytosolic alanyl aminopeptidase (AAP-S) was purified to homogeneity from human liver cytosol. The molecular weight of the purified enzyme was calculated to be approximately 98,000 on TOF-MS and 90,000 on SDS-PAGE in the presence of beta-ME. These findings suggest that the enzyme exists as a monomeric form in human liver cytosol. The enzyme rapidly hydrolyzed the substrates Ala-, Lys- and Phe-MCAs, and moderately hydrolyzed Met-, Leu-, Tyr- and Lys-Ala-MCAs at pH ranging from 7.5 to 8.0. The order of the K(cat)/K(m) values of AAP-S at the optimal pH was Arg->Arg-Arg->Met->Leu->Lys->Phe->Lys-Ala->Tyr->Ala-MCAs. It was strongly inhibited by bestatin, leuhistin, actinonin, amastatin, 1, 10-phenanthroline, DFP, PCMBS, Zn(2+), Cd(2+), Co(2+), Cu((2+)), Hg(2+) and puromycin. AAP-S was approximately 80 times more sensitive than human seminal plasma AAP (aminopeptidase N, membrane type). The amino acid sequence of the first 60 residues of AAP-S was highly homologous with the N-terminal amino acid sequence of the rat liver puromycin-sensitive enkephalin-degrading aminopeptidase. These physicochemical properties and findings indicate that AAP-S from human liver cytosol is identical to those of other puromycin-sensitive aminopeptidase(s). Furthermore, with immunohistochemistry the enzyme was strongly stained in the cytoplasm of liver cells and renal tubules, and was ubiquitously localized in various human tissues.

Lectin-histochemical detection of degenerative glycoconjugate deposits in human brain

Several lectins were used to study the localization of glycoconjugates in brain of elderly people and patients with Alzheimer type dementia (ATD) and Down's syndrome (DS). Five kinds of degenerated or deposited materials stained clearly by lectins specific to GalNAC, Gal, Fuc, and/or Man were recognized much in ATD and DS, less in elderly peoples, in addition to the binding of the lectins to neurons. (i) Round shape deposits called corpora amylacea (CA) which consisted of various sizes of round material, existed mainly on the surface of cerebral cortex and some in white matter of the brain. They were colored by Alcian blue (AB), Aldehyde fucsin (AF) and periodic acid shiff (PAS) and weakly by Hematoxylin (H), but not by Eosin (B). They showed clear reactivity with lectins specific to GalNAC, Gal, Fuc and Gal-GalNAC. (ii) Amorphous and variform amyloid deposits existed around blood vessels in the white matter were stained by thioflavin and lectins specific to GalNAC, Gal and Fuc, but not with Man specific lectins and PAS, AB, AF and HE. (iii) Another kind of amyloid deposits which showed a similar characteristic to the previous one and were recognized mainly in white matter and independent blood vessels. These deposits were stained by thioflavin but not by PAS, AB, AF and HE and showed good reactivity with lectins specific to GalNAC, Gal, Fuc, Gal-GalNAC, Gal-GIcNAc and Man. The reactivity with lectins specific to Gal, Fuc, and Man was seen in senile plaques (iv) and neurofibrillary tangles (v). Although at present we are unable to explain the origin of these deposits, it is clear from this study that the glycoconjugates form an integral part of the degeneration in the brain. The lectin staining with GS-I is useful in the forensic pathology to diagnose brain disorders at postmortem examination, since these lectin were able to detect five types of degeneration changes and/or deposits.

Molecular cloning and immunohistochemical localization of rat dipeptidyl peptidase III

Dipeptidyl peptidase III (DPP III) was purified to homogeneity from rat liver cytosol. The calculated molecular weight of the purified enzyme was 82845.6 according to TOF-MS, and 82000 on non-denatured PAGE and 82000 on SDS-PAGE in the absence or presence of beta-ME. These findings suggest that the enzyme assumes a monomeric form in rat liver cytosol. The enzyme rapidly hydrolyzed the substrate Arg-Arg-MCA and moderately hydrolyzed Ala-Arg-MCA in a pH range of 7. 5 to 9.5. The K(in), K(cat) and K(cat)/K(m) values of DPP III at optimal pH (pH 8.5) were 290 microM, 18.0 s(-1) and 6.21x10(4) s(-1)M(-1) for Arg-Arg-MCA and 125 microM, 4.53 s(-1) and 3.62x10(4) s(-1)M(-1) for Ala-Arg-MCA, respectively. DPP III was potently inhibited by EDTA, 1,10-phenanthroline, DFP, PCMBS, NEM, beta-ME and iodoacetamide. Furthermore, we screened a rat liver cDNA library using affinity-purified anti-rat DPP III rabbit IgG, and we determined the cDNA structure and deduced the amino acid sequence. The cDNA designated as lambdaRDIII-11 is composed of 2640 bp of nucleotides in length and encodes 738 amino acids in the coding region. Although the enzyme has a novel zinc-binding motif, HEXXXH in structure, DPP III is thought to belong to family 1 in clan MA in the metalloprotease kingdom. These findings suggest that DPP III is a metalloprotease that is probably regulated by SH modification. The DPP III antigen was extensively detected in the cytosol of various rat tissues by the immunohistochemical examination of the protein.

Age-related changes in contractile responses of rabbit lower urinary tract to endothelin

PURPOSE

As there are significant amounts of endothelin (ET) receptors in the mammalian urinary tract, we investigated the pharmacological properties and localization of ET receptors in the rabbit lower urinary tract as a function of age.

MATERIALS AND METHODS

The characteristics of ET receptors in bladder dome, trigone and urethra of 6 weeks and 6 months old male rabbits were determined using muscle bath and autoradiographic techniques.

RESULTS

ET-1 produces significant contractile responses in smooth muscle strips from bladder dome, trigone, and urethra in both 6 weeks and 6 months old rabbits. Although there was no significant difference in the maximum contractile response of urethral muscle strips to ET-1 between 6 weeks and 6 months old rabbits, the maximum responses to ET-1 were higher in both bladder dome and trigone of 6 weeks than 6 months old rabbits. A selective ETA receptor antagonist, BQ 610, shifted the concentration response curve to ET-1 to the right without decreasing maximal contractile responses in all regions from both age groups, whereas a selective ETB receptor antagonist, IRL 1038, had no significant effect on the contractile response in these tissues. Autoradiographic studies indicate that both ET receptor subtypes are expressed in bladder dome, trigone, and urethra with the ETA subtype being located only in the smooth muscle layers and the ETB subtype being located in both the urothelial and smooth muscle layers.

CONCLUSION

Our data indicate the presence of region- and age-dependent differences in the contractile properties of ET receptors in the male rabbit lower urinary tract. Although both ETA and ETB receptor subtypes are present in the smooth muscle layers, the ETA receptor is the sub-type that is primarily involved in the mediation of contractions.

Properties of alpha-1-adrenergic receptors in the rat prostate: effect of experimental diabetes

We studied the effects of 8 weeks of streptozotocin (STZ)-induced diabetes on the density and the pharmacological properties of alpha1-adrenoceptors in the rat prostate using receptor-binding experiments with [125I]iodo-2[beta-(4-hydroxyphenyl)-ethylaminomethyl]tetralone [125I]HEAT. Saturation experiments showed the presence of specific [125I]HEAT-binding sites in the control and diabetic rat prostate and that the induction of diabetes significantly decreased the density of [125I]HEAT-binding sites in the rat prostate. [125I]HEAT-binding sites in the prostate of both groups were inhibited by prazosin (nonselective), spiperone (alpha1B-selective), WB4101 and 5-methylurapidil (alpha1A-selective) and BMY7378 (alpha1D-selective) with the following rank order of Ki values: prazosin < WB4101 < 5-methylurapidil < spiperone < BMY7378, indicating a similar pharmacological profile of alpha1-adrenoceptor in the 2 groups. Comparing the Ki values of the rat prostate with those obtained from the rat submaxillary gland (alpha1A), rat spleen (alpha1B), rat vas deferens (alpha1A + alpha1B) and those reported for cloned alpha1D, indicates the predominance of the alpha1A + alpha1B or the alpha1A subtype in the rat prostate. The present study demonstrates that STZ-induced diabetes downregulates the expression of alpha1-adrenoceptor in the rat prostate, without significantly affecting the receptor subtype specificity.

Differential expression of c-fos following administration of two tremorgenic agents: harmaline and oxotremorine

The regional distribution of c-Fos expression in the brain after the administration of two tremorgenic agents was studied. In both the harmaline- and oxotremorin-treated rats, c-Fos-positive neurons were extensively distributed in the basal ganglia nuclei and the cerebellum. Additionally, in the harmaline-treated rats, numerous c-Fos-positive neurons were also distributed throughout the inferior olivary nucleus. In the oxotremorine-treated rats, while the inferior olive was not involved, c-Fos was strongly expressed in the neurons of the reticular thalamic nucleus, possibly due to the muscarinic effects of oxotremorine. The present study revealed that the inferior olive is selectively activated in the harmaline-administered animals and that the basal ganglia are involved in both harmaline- and oxotremorine-induced tremors.