Stop-flow studies of solute uptake in rat lungs

Stop-flow studies were used to characterize solute uptake in isolated rat lungs. These lungs were perfused at 8 or 34 ml/min for 10-28 s with solutions containing 125I-albumin and two or more of the following diffusible indicators: [3H]mannitol, [14C]urea, 3HOH, 201Tl+, or 86Rb+. After this loading period, flow was stopped for 10-300 s and then resumed to flush out the perfusate that remained in the pulmonary vasculature during the stop interval. Concentrations of 201Tl+ and 86Rb+ in the venous outflow decreased after the stop interval, indicating uptake from exchange vessels during the stop interval. The amount of these K+ analogs lost from the circulation during the stop interval was greater when the intervals were longer. However, losses of 201T1+ at 90 s approached those at 300 s. Because extraction continued after the vasculature had been flushed, vascular levels had presumably fallen to negligible levels during the stop interval. By 90 s of stop flow the vascular volume that was cleared of 201T1+ averaged 0.657 +/- 0.034 (SE) ml in the experiments perfused at 8 ml/min and 0.629 +/- 0.108 ml in those perfused at 34 ml/min. Increases in perfusate K+ decreased the cleared volumes of 201T1+ and 86Rb+. Uptake of [3H]mannitol, [14C]urea, and 3HOH during the stop intervals was observed only when the lungs were loaded at high flow for short intervals. Decreases in 201T1+ and 86Rb+ concentrations in the pulmonary outflow can be used to identify the fraction of the collected samples that were within exchange vessels of the lung during the stop interval and may help determine the distribution of solute and water exchange along the pulmonary vasculature.     

Effect of SB-205384 on the decay of GABA-activated chloride currents in granule cells cultured from rat cerebellum

1. 4-Amino-7-hydroxy-2-methyl-5,6,7,8,-tetrahydrobenzo[b]thieno[2,3-b]pyrid ine-3-carboxylic acid, but-2-ynyl ester (SB-205384) and other gamma-aminobutyric acid(A) (GABA(A)) receptor modulators were tested for their effects on GABA-activated chloride currents in rat cerebellar granule cells by use of the whole-cell patch clamp technique. 2. The major effect of SB-205384 on GABA(A)-activated current was an increase in the half-life of decay of the response once the agonist had been removed. This is in contrast to many GABA(A) receptor modulators that have previously been shown to potentiate GABA-activated currents. 3. This profile could be explained if SB-205384 stabilizes the channel in open and desensitized states so that channel closing is dramatically slowed. Such a modulatory profile may produce a novel behavioural profile in vivo.     

Levels of norepinephrine in rat cerebellum after administration of the convulsant 3-mercaptopropionic acid

The level of norepinephrine in rat cerebellum was assayed after the administration of the convulsant 3-mercaptopropionic acid. Decrease in norepinephrine was observed after the onset of seizure. The results were compared with those of GABA which were diminished both during and after convulsions. The decrease of GABA was prior to that of norepinephrine.     

Autoradiographic study on [3H]-[D-Ala2]-deltorphin-I binding sites in the rat brain

Previous biochemical and pharmacological studies have shown that [D-Ala2]-deltorphin-I (DADTI) has a high affinity and selectivity for delta-opioid receptors. In this study, designed to provide morphological details, the distribution of DADTI binding sites was examined by autoradiography on coronal, sagittal and horizontal frozen sections of adult rat brain. The sections were incubated with tritiated DADTI solution and exposed for 12 weeks to a 3H-sensitive film. DADTI labelling clearly demonstrated selective and high affinity binding sites of delta-opioid type in several brain regions, including olfactory system, neostriatum, nucleus accumbens, and cortical layers I-II and V-VI.     

Development and differentiation of glial precursor cells in the rat cerebellum

The development and differentiation of bipotential glial precursor cells has been studied extensively in tissue culture, but little is known about the distribution and fate of these cells within intact animals. To analyze the development of glial progenitor cells in the developing rat cerebellum, we utilized immunofluorescent, immunocytochemical, and autoradiographic techniques. Glial progenitor cells were identified with antibodies against the NG2 chondroitin-sulfate proteoglycan, a cell-surface antigen of 02A progenitor cells in vitro, and the distribution of this marker antigen was compared to that of marker antigens that identify immature astrocytes, mature astrocytes, oligodendrocyte precursors, and mature oligodendrocytes. Cells expressing the NG2 antigen appeared in the cerebellum during the last 3-4 days of embryonic life. Over the first 10 days of postnatal life, the NG2-labeled cells incorporated 3H-thymidine into their nuclei and their total number increased. At all ages examined, the NG2-labeled cells did not contain either vimentin-like or glial fibrillary acidic protein (GFAP)-like immunoreactivity, suggesting that they do not develop along an astrocytic pathway. NG2-labeled cells of embryonic animals expressed GD3 ganglioside antigens, a property of oligodendrocyte precursors, whereas NG2-positive cells of postnatal animals did not express GD3 immunoreactivity. Nevertheless, the NG2-labeled cells of the nascent white matter expressed oligodendrocyte-specific marker antigens. Cells lying outside of the white matter continued to express the NG2 antigen. In adult animals, the NG2-labeled cells incorporated 3H-thymidine. Glial cells isolated from adult animals and grown in tissue culture express the NG2 antigen and display the phenotypic plasticity characteristic of 02A progenitor cells. These findings demonstrate that a population of glial progenitor cells is extensive within both young and adult animals.     

In vitro polarographic studies of rat brain oxygen uptake in simulated uraemia and hepatic coma

The villi and crypts of the small intestine of the albino rat (Rattus norvigicus) have been enumerated and measured at different ages from 2 weeks to 8 months. The number of villi increased up to the third month of age and the number of crypts up to the eighth month. In the proximal intestine, the mean length of the villus base increased up to the fifth month as ridge-shaped villi were formed. Villus height was greater proximally than distally and this, and the crypt depth, remained constant from the end of the first month of age. The total villus circumference per unit area of intestine, and the villus circumference per crypt was the same proximally and distally, and was relatively constant after the first month of age. The total circumference of the crypt mouths per square millimeter of intestine was the same proximally and distally and, at all ages, was greater than the total villus circumference. The villus surface area per square millimeter of intestine, or per crypt, remained relatively constant after the first month and was greater proximally than distally, due only to the taller villi proximally. The change from finger-shaped to ridge-shaped villi did not affect the villus mucosal surface area. The changes in villus shape are probably not determined by differences in the rate of crypt cell production.     

Cytoplasmic expression of the leu-4 (CD3) antigen in developing Purkinje cells in the rat cerebellum

Urinary tract infection (UTI) is a very common medical disorder among women, and is a chronic, recurrent problem for a cluster of sufferers. The factors involved in the aetiology of recurrent UTI are not adequately understood. Most research and treatment has focused on the influence of medical factors, although clinical impressions suggest that psychological factors (behavioural and personality variables) may play an important role. Evidence is reviewed for the involvement of psychological factors in the aetiology and treatment of recurrent UTI in women. It is difficult to draw any clear conclusions concerning the role of such factors in recurrent UTI, given the relatively small amount of research to date and a number of methodological issues. Suggestions for appropriate methodology and research concerning the interplay of physical and psychological factors are made.     

Autoradiographic studies of cultures of cerebrospinal fluid lymphocytes in nonsuppurative meningitis

Morphologic and autoradiographic studies of cerebrospinal fluid lymphocytes in nonsuppurative meningitis showed that, in addition to blast cells synthesizing DNA in response to mitogens, blast cells not incorporating thymidine were present. The autoradiographic studies also showed small lymphocytes of the usual sizes incorporating 3H thymidine, indicating that they were in the growth phase of the cell cycle. The magnitude of the response of CSF lymphocytes from patients with tuberculous meningitis to purified protein derivative appeared specific. A response of this degree may be of value in the early diagnosis of tuberculous meningitis.     

Autoradiographic localization of vasopressin V1a receptors in the rat kidney using [3H]-SR 49059

Localization and characterization of binding sites of the selective non-peptide vasopressin receptor V1a ligand, [3H]-SR 49059, were investigated in the adult rat kidney by quantitative autoradiography using a fast-detecting radioluminographic phosphor-imaging plate system. [3H]-SR 49059, like the other V1a ligands used, showed a total absence of binding in the papilla, discrete and sparse labeling in the cortex and maximal binding in the outer part of the inner medulla. This labeling seemed to be mainly associated with medullary interstitial cells and vascular elements of the vasa recta. Conversely, [3H]-AVP intensely labeled the V2-enriched medulla-papillary portion of the kidney and, to a lesser extent, the cortical structures. [3H]-SR 49059 binding, quantified in the outer part of the inner medulla in rat kidney sections, was time-dependent, reversible, saturable and a single class of high affinity binding sites (Kd = 1.48 +/- 0.16 nM) was identified. The relative potencies of the reference peptide and non-peptide compounds to inhibit [3H]-SR 49059 binding confirm the V1a nature of the site and the stereospecificity of this binding. Thus, [3H]-SR 49059 allows the mapping and characterization of the V1a receptor population present in the rat kidney. The stability and the highly selective affinity of this non-peptide ligand for rat and human V1a receptors make it a suitable probe for the localization of V1a receptors in organs expressing heterogeneous populations of receptors.     

Developmental fates and migratory pathways of dividing progenitors in the postnatal rat cerebellum

To investigate the developmental fates and the migratory pathways of dividing progenitors in both the white matter (WM) and the external granule layer (EGL) in the early postnatal rat cerebellum, a replication-deficient retrovirus carrying the beta-galactosidase gene (BAG) was injected into the deep cerebellar tissue or the EGL of postnatal rats to label dividing progenitors. After 1-3 days post-injection (1-3 dpi) of BAG into the deep cerebellar tissue of postnatal day 4/5 (P4/5) rats, labeled immature, unipolar cells were found mainly in the WM. From 4 to 6 dpi, similar cells appeared in the internal granule (IGL), Purkinje cell, and molecular layers, although about half of the labeled cells still resided in the WM and appeared immature. The first morphologically definable Bergmann glia, astrocytes, and oligodendrocytes were also observed. From 14 to 20 dpi, most labeled cells had developed into Bergmann glia, astrocytes, oligodendrocytes, and interneurons in their appropriate layers. When BAG injections were performed at P14, unipolar cells were initially observed, but the majority of these differentiated into myelinating oligodendrocytes in the WM and IGL by 17 dpi. Few immature cells were labeled by injections administered at P20, and these did not develop into mature glia, but into cells with lacy, fine processes, possible representing immature oligodendrocytes. In contrast, BAG-labeled progenitors of EGL produced only granule neurons. Thus, within the first 2 postnatal weeks, dividing progenitors in the WM migrate as immature cells into the cortex before differentiating into a variety of glia and interneurons. The genesis of oligodendrocytes continues through the 2nd postnatal week and largely ceases by P20. EGL cells do not produce glia, but only granule cells.     

Effects of various isoquinoline alkaloids on in vitro 3H-dopamine uptake by rat striatal synaptosomes

Various alkaloids having an isoquinoline skeleton from different species of the Annonaceae, Fumariacae, and Aristolochiacae (aporphine, cularine, benzylisoquinoline, and bisbenzylisoquinoline derivatives) were tested for their ability to inhibit in vitro 3H-dopamine uptake by rat striatal dopamine D1 3H-SCH 23390 AND D2 3H-raclopride binding sites. Except for some aporphine derivatives (anonaine [1], norstephalagine [2], isopiline [3]) and some bisbenzylisoquinoline alkaloids (dimethylgrisabine [27], antioquine [28], obaberine [29], isotetrandrine [30]) that displayed affinities of the same order as the reference compounds (nomifensine [38], amineptine [39], dexamphetamine [40]), the other tested products had low, or no, affinity on the 3H-dopamine uptake since, in comparison, its affinity at dopamine D1 3H-SCH 23390 and D2 3H-raclopride binding sites was low. These data suggest that it could be possible to synthesize anonaine-like products displaying intense dopamine-uptake inhibitory properties, which could lead to a potential antidepressant activity.     

The uptake of 3-deoxy-3-fluoro-D-glucose by synaptosomes from rat brain cortex

D-[3-3H]-3-deoxy-3-fluoroglucose was synthesized chemically and shown to be transported into rat brain synaptosomes by a saturable process with a Km 6.2 x 10(-4) M and a Vmax 2.8 nmole x mg protein-1. After an initial, rapid period of transport, further uptake of the fluorosugar is restricted by the rate of its phosphorylation. Both D-glucose and cytochalasin B are competitive inhibitors of 3-deoxy-3-fluoro-D-glucose transport with Ki values of 93 micron and 6.0 x 10(-7) M, respectively. Phloretin, N-ethylmaleimide and p-chloromercuribenzoate also inhibit the fluorosugar uptake, whereas ouabain and changes in K+, Na+, Mg2+ and Ca2+ ions have only a small effect. The recorded 3-deoxy-3-fluoro-D-glucose influx is slightly reduced by potassium cyanide, antimycin A, 2,4-dinitrophenol, and rotenone. The uptake reduction caused by these four reagents is relieved by the addition of exogenous ATP. The possible influence of hexokinse activity on the uptake process is discussed.     

Serotoninergic control of the activity and expression of glial GABA transporters in the rat cerebellum

OBJECTIVE: The purpose of the study was to compare staff versus patient perceptions of the causes and emotional impact of verbal and physical aggression on a psychiatric inpatient unit, and the corrective measures each group would endorse. METHODS: Fifty-four patients and 32 nursing staff members responded to similar questions about physical and verbal aggression. They also reported their emotional responses to aggression and steps they would endorse to reduce aggression at the medical center. Data was analyzed by chi-square tests for proportion comparisons between groups. RESULTS: "Verbal Abuse" was viewed an important contributor to physical aggression. Staff stressed patient substance abuse and violent lifestyles. Patients focused on the use of involuntary procedures and cultural differences between patients and staff. CONCLUSIONS: Patients endorsed more restrictive safety measures as long as the measures such as metal detectors and searches were applied to staff and visitors, as well as patients. Patients requested more input into decision-making processes through patient-staff workgroups.