The Involvement of Dopamine in Strengthening Cortical Signals Activating NMDA Receptors in the Striatum (a hypothetical mechanism)

A possible mechanism is proposed for the enhancement/weakening of those cortical signals in the cortex-basal ganglia-thalamus-cortex neural network which induce/do not induce opening of NMDA channels in the spiny neurons of the striatum and which can be regarded as strong/weak in terms of this measure. The mechanism is based on the modulatory influences of dopamine on changes in the efficiency of corticostriatal inputs. In the absence of dopamine, relative increases in the intensity of strong (weak) cortical signals can lead to the induction of long-term potentiation (depression) of corticostriatal synapses. In this case, because of the differently directed influences on thalamic cells of signals passing via strionigral and striopallidal cells, strong signals at the output of the thalamus are weakened, while weak signals are strengthened. Activation of dopamine D₁ (D₂) receptors on strionigral (striopallidal) neurons may facilitate increases in the extent of long-term potentiation/depression (decreases in the extent of long-term potentiation/depression or induction of long-term potentiation/depression). The consequence of this is that strong signals at the output of the thalamus can be strengthened synergistically, while weak signals cab be weakened synergistically. Background cortical signals evoking tonic release of dopamine in the striatum can decrease strengthening because of weakening of the modulatory influence of dopamine on the modification of corticostriatal synapses.     

The effect of high altitude on the protein composition of human blood

Summary Twelve healthy young individuals had the protein composition of their blood determined in Stalinabad (850 m) and during their sojourn in the mountain of East Pamir between the months of May and October, 1958, at the altitude of 4200 m.During the first month of sojourn at high altitude, the total concentration of protein went up, while towards the end of the 4 month period it dropped somewhat, but still remained above the initial level. The relative and the absolute albumin content in the blood serum dropped immediately after the ascent and remained low for a month after descent from 4200 m to 850 m. The figures for ₁-, - and -globulins rose immediately after ascent. During the 4 month stay at high altitude, the ₁- -globulins went back to normal. During the first month after descent, figures for ₁-, - and -globulins were higher than the initial levels; ₂-globulin went up only after descent. Oncotic pressure of blood rose during the first month after ascent, then returned to normal at the expense of increased concentration of the globulin fraction, which compensates for the decreased albumin content in blood serum.(Presented by Active Member AMN SSSR S. R. Severin) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 50, No. 10, pp. 78–82, October, 1960.     

Die optische Rotationsdispersion isolierter Paraproteine

Zusammenfassung Die aus dem optischen Drehungsvermögen abgeleiteten Konstanten elektrophoretisch isolierterA-Paraproteine werden mitgeteilt. Die Dispersionskonstante _c weist keine Unterschiede zwischen den 3 ParaproteingruppenG,A undM auf. Der nach dem Verfahren vonMoffitt undYang ermittelte Parameterb ₀ wurde zu Schätzung des-Helixgehaltes benutzt. Er betrug in den 7 untersuchten Paraproteinen 0. Für den Parameter —a ₀ ergab sich ein Mittelwert von 276,0±35,1. FürG-Paraprotein wurde in früheren Untersuchungen ein solcher von 312,8±20,8, fürM-Paraprotein 217,9±26,7 gefunden. Der Mittelwertsvergleich zeigte Signifikanz der Konstantea ₀ für jede der 3 Paraproteingruppen.a ₀ beschreibt demnach gruppenspezifische Eigenschaften von Paraproteinen. Die für den Wert vona ₀ maßgeblichen strukturellen Voraussetzungen sind kaum bekannt. Sie werden am ehesten die die spezifischen Antigendeterminanten tragenden H-Ketten des Paraproteinmoleküls betreffen.

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Summary The constants of the optical rotatory dispersion of electrophoretically isolatedA-paraproteins are communicated. There is no difference between theG,A andM-paraprotein group with respect to the dispersion constant _c . The parameterb ₀ was measured according toMoffitt andYang. The-Helix-content calculated fromb ₀ of 7A-paraproteins was sero (0).The mean value of the parameter —a ₀ was 276±35,1. In earlier experiments it was found that —a ₀ forG-paraproteins is 312,8±20,8 and forM-paraproteins 217,9±26,7. The parametera ₀ of each group differs significantly from the others; in other words,a ₀ is group specific. The structural implications of these findings are discussed.

     

Analysis of γδ+ T cells in peripheral blood of children with perinatal human immunodeficiency virus (HIV) infection

The present study examined CD8 antigen expression and variable (V) gene segment usage by T cell receptor (TCR)-⁺ lymphocytes in peripheral blood of symptomatic children with perinatal HIV infection. The relative number of ⁺, CD8⁺ T cells in most of the infected children was higher than that in uninfected children from HIV⁺ or HIV^– mothers and correlated with the immunodeficiency status of the patients. Infected infants and children over 1 year old also showed an increased proportion of V1-J1⁺ T lymphocytes. CD8 expression on those cells was higher in infected than in uninfected infants and children. Sequence analysis of the gene rearrangement of the predominant V1 family in peripheral blood of three HIV⁺ donors revealed extensive junctional diversity. These results suggest that the V skewing in the majority of HIV⁺ children reflects peripheral expansion of V1-J1⁺ T lymphocytes early in life, which might be involved in the mechanisms of HIV-induced immunodeficiency.     

Increase in TCRγδ T lymphocytes in synovia from rheumatoid arthritis patients with active synovitis

To determine the relative presence of TCR+ and TCR+ T cells in synovial tissue from patients with various types of inflammatory synovitis and in tissues from patients with a number of chronic T cell-mediated conditions, we stained frozen tissue sections with monoclonal antibodies in indirect immunofluorescence assays. In tissues obtained from patients with chronic T cell-mediated granulomatous conditions (Wegener's granulomatosis, lymphomatoid granulomatosis, granuloma annulare, Langerhan's cells granulomatosis, pigmented villonodular synovitis, Takayasu's arteritis, and talc granulomatosis), the T cells present were predominantly TCR+, without an increased presence of TCR+ cells. In contrast, 6 of 14 (43%) synovia from patients with rheumatoid arthritis (RA) showed increased TCR+ T cells (3–10 cells/hpf). The RA synovia with increased TCR+ cells present had an increased tissue inflammation score compared to RA synovia with few TCR+ cells [18.6±5.8 versus 11.6±4.2 (mean±SE),P<0.05]. In contrast, synovia from patients with osteoarthritis, systemic lupus erythematosus, and trauma did not show an increased presence of TCR+ T cells. Thus, in cellular inflammatory infiltrates the presence of increased TCR cells is not a component of noninfectious granulomatous inflammation but is found in approximately 40% of RA synovia with high levels of inflammation.     

Estradiol attenuation of beta-amyloid-induced toxicity: a comparison o.

17-estradiol (E2) has been shown to attenuate the toxicity of -amyloid peptides (A) in neuronal cultures with the effective concentration of E2 ranging from low nM to high M. This study compares the effective neuroprotective concentration of E2 against both A-mediated toxicity in a human neuroblastoma cell line, SK-N-SH using cellular reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) as an endpoint to the effective E2 concentration obtained using a calcein acetoxymethyl ester (calcein AM) viability assay. The minimum E2 concentration required for protection varied 1000-fold between the two viability assays with 1 nM E2 conferring significant protection in the calcein AM assay but 1 M E2 required for significant protection in the MTT assay. Interestingly, the maximal inhibition of MTT reduction occured at sub-toxic A concentrations and did not correlate with other markers of cellular viability including calcein fluorescence, dye exclusion (propidium iodide or trypan blue), cellular ATP levels, or reduction of another tetrazolium dye, 5-(3-carboxymethoxyphenyl)-2-(4,5-dimethylthiazolyl)-3-(4-sulfophenyl) tetrazolium (MTS). By contrast, there was no difference between the MTT and calcein AM assays with respect to H₂O₂ toxicity or the neuroprotective effectiveness of 10 nM E2 against H_{2 2} toxicity. These results indicate that low concentrations of E2 can attenuate A and H₂O₂ toxicity in a human neuroblastoma cell line. Further, these results suggest that the MTT assay is not an appropriate assay for the determination of E2-mediated attenuation of A toxicity.     

Direct immuno-electron microscopy and some morphological features of hog cholera virus

Summary Characteristic particles of hog cholera virus were identified by direct immuno-electron microscopy. The virion is 40–50m, often asymmetrically shaped, and is enveloped in a membrane that bears 12–15 m surface projections. The surface projections are shear-sensitive and are antigenically different from the virion's envelope. They may represent hog cholera virus soluble antigen.     

Evidence for a multigenic system controlling methyl-β-carboline-3-carboxylate (β-CCM)-induced seizures

-CCM is a -carboline known to have properties opposite to those of benzodiazepines. Our approach was to analyze, in mice, the genetic mechanisms involved in -CCM-induced myoclonic seizures using recombinant congenic strains and F₁ hybrids issued from these strains. Our aim was to define the extent of the multigenic character of -CCM-induced myoclonic seizures, while also evaluating the distribution of the strength of the genes implicated in this trait. The results show that the control of reactivity to -CCM is multigenic with notable epistatic involvement.     

Identification and quantitation of cortisol metabolites in rat liver homogenate and -slices

Summary Cortisol-1, 2-H³ was incubated with rat liver homogenate and/or rat liver slices in the presence of a NADPH-generating system. The following metabolites could be identified in adult male rats: -cortol, allo--cortol, 3-allo--cortol, 20-hydroxy-cortisol, 11, 17, 20, 21-tetrahydroxy-5-pregnan-3-one, 3-allotetrahydrocortisol, tetrahydrocortisol, trace amounts of allotetrahydrocortisol and two highly polar metabolites only partly identified. In female rats only tetrahydrocortisol, allotetrahydrocortisol and allodihydrocortisol could be detected in significant amounts.The radioactive metabolites mentioned above were localized and quantitated on paper chromatograms by a 4-radiochromatogram scanner. A nearly perfect correlation was found between these results so obtained and those given by liquid-scintillation counting of each metabolite after its elution from the paper.Part of this work was supported by grant n° 695 of the National Fonds voor Wetenschappelijk Geneeskundig Onderzoek.Stagiair of the Nationaal Fonds voor Wetenschappelijk Onderzoek.     

Isoenzymes of γ-glutamyl transpeptidase in liver diseases

Summary A new method for the separation of isoenzymes of-glutamyl-transpeptidase is described, using electrophoresis on acetate cellulose gel and a developing solution composed by-glutamyl-naphthylamide, and a colored diazonium compound.The method permits the separation of up to four different isoenzymes, which we called-GT₁,-GT₂,-GT₃,-GT₄, the first two showing an electrophoretic migration similar to that of ₁- and ₂-globulins and the other two to that of-globulins.The present technique has proved its usefulness in detecting isoenzymes in serum with values of total-glutamyl-transpeptidase higher than 80 U/L.The application of this method in 52 patients with different types of biliary obstruction and hepatocellular damage has shown that it provides new possibilities in differential diagnosis.     

Evidence for a direct relationship between mitochondrial genome organization and regeneration ability in hexaploid wheat somatic tissue cultures

Summary Embryogenic and non-embryogenic long-term callus cultures of hexaploid wheat exhibit differences in the organization of their mitochondrial genome. Embryogenic and non-embryogenic fractions of callus cultures initiated from immature embryos of the wheat cultivar Chinese Spring have been isolated and subsequently subcultured. DNA-DNA hybridization experiments using labelled cloned wheat mitochondrial DNA fragments have shown that the mitochondrial DNA organization of embryogenic subcultures derived from embryogenic parts of Chinese Spring calli is closely related to that of the initial Chinese Spring calli, while non-embryogenic subcultures derived from non-embryogenic fragments of Chinese Spring calli exhibit a mitochondrial DNA organization similar to that found in non-embryogenic calli derived from cultivar Aquila. In addition, somatic tissue cultures initiated from three other non-embryogenic wheat cultivars (Talent, Thésée and Capitole) display mitochondrial DNA arrangements similar to those found in cultivar Aquila. These results strongly suggest that, in wheat callus cultures, a particular mitochondrial genome organization is correlated with the ability of cultured cells to regenerate whole plants.Abbreviations mtDNA mitochondrial DNA - ctDNA chloroplast DNA - rRNA ribosomal RNA - kb kilobase pair - cv cultivar - 2,4-D 2,4-dichlorophenoxyacetic acid     

Ablation of primary afferent terminals reduces nicotinic receptor expression and the nociceptive responses to nicotinic agonists in the spinal cord

A variety of studies indicate that spinal nicotinic acetylcholine receptors modulate the behavioral and autonomic responses elicited by afferent stimuli. To examine the location of and role played by particular subtypes of nicotinic receptors in mediating cardiovascular and nociceptive responses, we treated neonatal and adult rats with capsaicin to destroy C-fibers in primary afferent terminals. Reduction of C-fiber terminals was ascertained by the loss of isolectin B4, CGRP and vanilloid receptors as monitored by immunofluorescence. Receptor autoradiography shows a reduction in number of epibatidine binding sites following capsaicin treatment. The reduction is particularly marked in the dorsal horn and primarily affects the class of high affinity epibatidine binding sites thought to modulate nociceptive responses. Accompanying the loss of terminals and nicotinic binding sites were significant reductions in the expression of 3, 4, 5, 2 and 4 nicotinic receptor subunits in the superficial layers of the spinal cord as determined by antibody staining and confocal microscopy. The loss of nicotinic receptors that follows capsaicin treatment results in attenuation of the nociceptive responses to both spinal cytisine and epibatidine. Capsaicin treatment also diminishes the capacity of cytisine to desensitize nicotinic receptors mediating nociception, but it shows little effect on intrathecal nicotinic agonist elicited pressor and heart rate responses. Hence, our data suggest that 3, 4, 5, 2 and 4 subunits of nicotinic receptors are localized in the spinal cord on primary afferent terminals that mediate nociceptive input. A variety of convergent data based on functional studies and subunit expression suggest that 3 and 4, in combination with 2 and 5 subunits, form the majority of functional nicotinic receptors on C-fiber primary afferent terminals. Conversely, spinal nicotinic receptors not located on C-fibers play a primary role in the spinal pathways evoking spinally coordinated autonomic cardiovascular responses.     

Neural representation of response category and motor parameters in monkey prefrontal cortex

Conditional motor behavior, in which the relationship between stimuli and responses changes arbitrarily, is an important component of cognitive motor function in primates. It is still unclear how cognitive processing for conditional motor control determines movement parameters to directly specify motor output. To address this issue, we studied the neuronal representation of motor variables relating to conditional motor control and also directly to the metrics of motor output in prefrontal cortex (PFC). Monkeys were required to generate a force that fell within one of two categories (small and large). We found that most PFC neurons were activated as a function of force category, suggesting a role in conditional motor control. At the same time, we found that activity in many PFC neurons varied continuously with the force that was eventually produced, suggesting they participated in specifying the metrics of movements as they were executed. The results suggest that the PFC neural population encodes both what motor response should be performed and how the selected movement should be realized immediately after the visual instruction.     

On the terms “reticulosis” and “reticulum cell sarcoma” with regard to the modern concept of the monocyte macrophage system

Summary The terms reticulosis and reticulum cell sarcoma (= malignant lymphoma, histiocytic type) are discussed regarding the modern concept of the monocyte macrophage system which today has replaced the ancient theory of the reticuloendothelial system. The monocyte macrophage system is not independent, but closely related to the myeloid system. Thus, a third blood forming system as was believed in the case of RES does not exist. Phagocytic reticulum cells of the various hematopoietic organs are highly activated monocyte-derived macrophages. All those conditions formerly termed reticuloses have been found to belong either to the myeloid or to the lymphatic system. Considering the reticulum cell sarcomas or malignant histiocytic lymphomas, most of them seem to be of lymphatic rather than of macrophage origin, representing highgrade malignant lymphomas, possibly immunoblastic sarcomas. No relationship between these tumours and the monocyte macrophage system has been established, so far. Therefore, the terms reticulosis and reticulum cell sarcoma should be no longer used in order to avoid confusion, in order to stimulate sufficient diagnostic efforts which will really clarify such cases, and in order to give full credit to modern results of hematopathology.     

Expression of cytokine genes in adhesions on uterine tubes

We studied expression of genes of interleukins, interferon-, tumor necrosis factor-, and transforming growth factor-₂ in adhesions on uterine tubes. In tubal adhesions the intensity of production of mRNA for proinflammatory cytokines, antiinflammatory cytokine interleukin-10, and regulator of cell proliferation surpassed that in normal tissues by 2.5-7.4, 2.2, and 50.2 times, respectively. Correlations were found between production of mRNA for tumor necrosis factor- and transforming growth factor-₂, interleukin-12, and interferon- and interleukin-12 and transforming growth factor-₂. Our results suggest that expression of these genes during adhesion formation is regulated by the feedback mechanism.     

Three-dimensional reconstruction of transmitter-identified central neurons by “en bloc” immunofluorescence histochemistry and confocal scanning microscopy

Summary A new method for three-dimensional reconstruction of transmitter-identified neurons is presented which involves en bloc immunofluorescence histochemistry and confocal scanning microscopy. The technique was applied to different types of neurons in the rat brain and lamprey spinal cord. Thick sections or tissue blocs (50–200 m thick) were incubated with antisera against neuropeptides or monoaminergic markers, followed by fluorescent secondary antibodies. Three-dimensional reconstructions were obtained by scanning the preparations in sequential focal planes with a thin laser beam, while sampling the emitted light in each focal plane. The method is convenient and can be applied to a wide variety of neuron types. The reconstructions obtained are accurate since the optical serial sections of the specimen are perfectly aligned, and optic disturbances such as halo phenomena do not occur.     

Roles of inositol trisphosphate and protein kinase C in the spontaneous outward current modulated by calcium release in rabbit portal vein

We examined the effects of heparin, guanosine nucleotides, protein kinase C (PKC) modulators, such as phorbol 12,13-dibutylate (PDBu) and H-7 on Ca²⁺-dependent K⁺ currents in smooth muscle cells of the rabbit portal vein using the whole-cell patch-clamp technique, to explore the effects of PKC on the oscillatory outward current (I _oo). Neomycin (30 M), an inhibitor of phospholipase C, and intracellular applications of heparin (10 g/ml) and guanosine 5-O-(2-thiodiphosphate) (GDP[S]; 1 mM) partly but consistently inhibited the generation of I _oo, whereas a higher concentration of heparin (100 g/ml) transiently enhanced then suppressed the generation of I _oo. Inhibition of I _oo generation by heparin was more powerful at the holding potential of + 20 mV than at –20 mV. Inositol 1,4,5-trisphosphate (InsP ₃; 30 M) continuously generated I _oo at holding potentials more positive than –60 mV. Noradrenaline (10 M) and caffeine (3–20 mM) transiently augmented, then reduced the generation of I _oo. Heparin (10 g/ml) completely inhibited responses induced by InsP ₃ and noradrenaline, but not those induced by caffeine. Intracellular application of guanosine 5-triphosphate (GTP; 200 M) or low concentrations of guanosine 5-O-(3-thiotriphosphate) (GTP[S]; 3 M) continuously augmented the generation of I _oo. High concentrations of GTP[S] (10 M) transiently augmented, then inhibited I _oo. Neither GTP[S] nor noradrenaline induced the transient augmentation or the subsequent inhibition of I _oo when applied in the presence of GDP[S] (1 mM), neomycin (30 M) or heparin (10 g/ml). PDBu (0.1 M) reduced the generation of I _oo but failed to produce an outward current following application of caffeine (3–5 mM). This action of PDBu was inhibited by pretreatment with H-7 (20 M). In the presence of H-7, GTP[S] continuously enhanced the generation of I _oo. The suppression of the generation of I _oo during application of noradrenaline (10 M) was reduced by pretreatment with H-7. Thus both InsP₃ and protein kinase C contribute to the generation of I _oo in smooth muscle cells of the rabbit portal vein and heparin is not a specific InsP ₃ antagonist on the InsP ₃-induced Ca²⁺-release channel (PIRC). InsP ₃ opens PIRC and protein kinase C may deplete the stored Ca²⁺ by either inhibiting the reuptake of Ca²⁺ or by enhancement of the releasing actions of InsP ₃.     

On the regulation of the expressed L-type calcium channel by cAMP-dependent phosphorylation

The Ca²⁺ channel subunits _1C-a and _1C-b were stably expressed in Chinese hamster ovary (CHO) and human embryonic kidney (HEK) 293 cells. The peak Ba²⁺ current (I _Ba) of these cells was not affected significantly by internal dialysis with 0.1 mM cAMP-dependent protein kinase inhibitor peptide (mPKI), 25 M cAMP-dependent protein kinase catalytic subunit (PKA), or a combination of 25 M PKA and 1 M okadaic acid. The activity of the _1C-b channel subunit expressed stably in HEK 293 cells was depressed by 1 M H 89 and was not increased by superfusion with 5 M forskolin plus 20 M isobutylmethylxanthine (IBMX). The _1C-a·₂·₂/ complex was transiently expressed in HEK 293 cells; it was inhibited by internal dialysis of the cells with 1 M H 89, but was not affected by internal dialysis with mPKI, PKA or microcystin. Internal dialysis of cells expressing the _1C-a·₂·₂/ channel with 10 M PKA did not induce facilitation after a 150-ms prepulse to +50 mV. The Ca²⁺ current (I _Ca) of cardiac myocytes increased threefold during internal dialysis with 5 M PKA or 25 M microcystin and during external superfusion with 0.1 M isoproterenol or 5 M forskolin plus 50 M IBMX. These results indicate that the L-type Ca²⁺ channel expressed is not modulated by cAMP-dependent phosphorylation to the same extent as in native cardiac myocytes.     

Summation and adaptation in stimulation of the motor cortex in adult and newborn animals

Summary In rabbits and their progeny an investigation was made of summation and adaptation of the neurones of the motor cortex; unipolar stimulation was used, and the muscular response recorded. Two types of summation curves were found: exponential and Y-shaped,, and were related to the direct and indirect summation of stimulation. In adults, Y-shaped summation curves were more frequent, whereas in rabbits aged 24 h exponential curves preponderted. We found very little capacity for adaptation at any age.(Presented by Active Member AMN SSSR A. F. Turom) Translated from Byulleten Éksperimental'noi Biologii i Medisiny, Vol. 55, No. 6, pp. 3–7, June, 1963     

Beitrag zur Frage einer gestörten Nierenfunktion bei exogen-alimentärer Fettsucht

Zusammenfassung Bei 15 nierengesunden Fettsüchtigen und 17 normalgewichtigen Personen bestimmten wir simultan Inulin- und Paraaminohippursäure-Clearance. Außerdem untersuchten wir die Beziehung zwischen den absoluten Clearance-Werten einerseits sowie tatsächlicher und idealer Körperoberfläche andererseits.Nach unseren Untersuchungen werden die Werte der Nieren-Clearance (ml/min/1,73 m²) Adipöser erheblich von der gewählten Bezugsgröße — der tatsächlichen oder idealen Körperoberfläche — beeinflußt. Durch Regressionsanalysen ließ sich zeigen, daß bei überernährten Probanden zwischen Glomerulumfiltrat und ihrer idealen Körperoberfläche ein signifikanter Zusammenhang bestand. Keinerlei Beziehung ergab sich für Inulin-Clearance und tatsächliche Körperoberfläche sowie für den effektiven Nierenplasmastrom einerseits und tatsächliche bzw. ideale Körperoberfläche andererseits. Die Frage, welche der Bezugsgrößen bei klinischen Clearance-Bestimmungen Fettsüchtiger zu verwenden ist, beantworteten wir sowohl für Inulin- als auch PAH-Clearance zugunsten der idealen Körperoberfläche.Unter Berücksichtigung der idealen Körperoberfläche lag das Glomerulumfiltrat der Fettsüchtigen im Mittel signifikant über dem des Vergleichskollektivs, während ihre PAH-Clearance durchschnittlich normal, bei 2 von 15 Adipösen erniedrigt ausfiel. Die Filtrationsfraktion war gegenüber der normalgewichtiger Personen im Mittel signifikant erhöht. Als Grund der veränderten Nieren-Clearance Fettsüchtiger werden funktionelle Einflüsse diskutiert.

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Summary Renal clearance rates (ml/min) of inulin (C_In) and paraamino-hippuric acid (C_PAH) were determined simultaneously in 15 obese patients with healthy kidneys and 17 persons of normal weight. C_In and C_PAH were computed to the standard unit 1,73 m² body surface area. Individual surface areas are calculated on the basis of real and ideal body weight. Our investigations show that the rates of renal clearance (ml/min/1,73 m²) depend to a considerable extent upon the selected surface area-actual or ideal body surface. Analysis indicates that in obese patients a significant connection exists between glomerulum filtration (C_In) and the ideal surface area. No connection was established for inulin clearance (C_In) and actual surface area, nor for C_PAH and real and ideal body surface area. In the determination of clinical clearance rates C_In and C_PAH both should in cases of obesity be computed to the ideal surface area. The mean glomerular filtration of obese persons was found to lie significantly above the mean value of persons of normal weight. C_PAH was normal except in two patients which had lowered paraamino-hippuric acid clearances. The filtration fraction was on average significantly above that of the persons of normal weight. Functional influences are discussed as the reason for the different renal clearance values of obese persons.