Loss of hyaluronan in the basement membrane zone of the skin correlates to the degree of stiff hands in diabetic patients

Glycosaminoglycans are important components of all extracellular matrices. One of the glycosaminoglycans is hyaluronan, which is ubiquitously distributed throughout the connective tissue. Hyaluronan is especially abundant in the skin, in which it is of both structural and functional importance. This study describes the localization and distribution of hyaluronan in the skin of healthy individuals and of 23 patients with insulin-dependent diabetes mellitus and various degrees of limited joint mobility. In normal skin, hyaluronan staining was seen in all layers but most prominently in the papillary dermis and the basement membrane zone. In the skin from diabetic patients with normal or only moderately restricted mobility of the hands (limited joint mobility grades 0 and 1), the distribution of hyaluronan was similar to that of normal skin. In the skin of patients with severe restriction in joint mobility (limited joint mobility grade 2) the staining pattern was significantly different with weak hyaluronan staining in the papillary dermis and the basement membrane zone almost devoid of hyaluronan. Moreover, an increased epidermal thickness in the latter patients was evident as well as a pronounced hyaluronan staining compared with normal epidermis.     

A novel quantitative dual-isotope method for simultaneous ventilation and perfusion lung SPET

A quantitative dual-isotope single-photon emission tomography (SPET) technique for the assessment of lung ventilation (V) and perfusion (Q) using, respectively, technetium-99m labelled Technegas (140 keV) and indium-113m labelled macro-aggregated albumin (392 keV), is presented, validated and clinically tested in a healthy volunteer. In order to assess V, Q and V/Q distributions in quantitative terms, algorithms which correct for down scattering, photon scattering and attenuation, as well as an organ outline algorithm, were implemented. Scatter and down-scatter correction were made in the spatial domain by pixel-wise image subtraction of projection-dependent global scattering factors obtained from the energy domain. The attenuation correction was based on an iterative projection/back-projection method. All studies were made on a three-headed SPET system (Trionix) with medium-energy parallel-hole collimators. The set of input data for quantification was based on SPET acquisition of emission data in four separate energy windows, the associated cumulative energy spectra and transmission data. The attenuation correction routine as well as the edge detection algorithm utilized data from (99m)Tc transmission tomography. Attenuation data for (113m)In were obtained by linear scaling of the (99m)Tc attenuation maps. The correction algorithms were experimentally validated with a stack phantom system and applied on a healthy volunteer. The mean difference between the corrected SPET data of the dense stack lung phantom and those obtained from the corresponding scatter- and attenuation-"free" version was only 1.9% for (99m)Tc and 0.9% for (113m)In. The estimated fractional V/Q distribution in the 3-D lung phantom volume had its peak at V/Q=1, with a width (FWHM) of 0.31 due to noise, particularly in the (113m)In images, and to partial volume effects. For a healthy volunteer, the corresponding values were 0.9 and 0.35, respectively. This method allows accurate assessment of radionuclide distribution on a regional basis. For basic lung physiology and clinical practice, the method allows assessment of the global frequency functions of the V, Q and V/Q distributions.     

A comparison between flow cytometric assessment of S-phase fraction and Nottingham histologic grade as prognostic instruments in breast cancer

Flow cytometric DNA analysis with assessment of S-phase fraction and DNA ploidy was compared to Nottingham histologic grade. The study population consisted of 654 patients who presented between 1987 and 1996 with primary operable breast cancer and whose tumours had been analysed for S-phase fraction and DNA ploidy at the time of surgery. Grade, tumour size, node status, steroid receptor status, age, S-phase fraction and DNA ploidy were analysed univariately and multi-variately in a Cox proportional hazard analysis. In the univariate analyses all parameters were statistically significantly associated with breast cancer mortality during the follow-up period of 2–11 years. The most powerful predictor of death from breast cancer in the multiple regression analysis was grade. Patients with grade 1 tumours have excellent prognosis. We conclude that tumour grade is a strong prognostic indicator applicable to all breast cancer patients, regardless of size and nodal status, and advocate its general use.     

Possible morphological substrates for GABA-mediated presynaptic inhibition in the lamprey spinal cord

Gamma-aminobutyric acid (GABA) neurons intrinsic to the lamprey spinal cord are known to modulate synaptic transmission from interneurons active during locomotion and from mechanosensory dorsal cells. Many of these physiological effects are presynaptic. To establish the morphological substrates for these axo-axonic interactions, an ultrastructural analysis was performed with an antiserum to fixed GABA. The GABA immunoreactivity (ir) was detected by postembedding peroxidase-antiperoxidase and immunogold techniques. GABA-ir terminals were found to make appositions with unlabelled axons located in the dorsal columns and in the ventrolateral aspect of the spinal cord. In the ventrolateral part of the cord, similar appositions between different GABA-ir terminals were also observed. The immunolabelled terminals contained spherical to pleomorphic synaptic vesicles, and also glycogen granules and dense core vesicles. In some cases, the fine structure of the contacts between immunogold-labelled terminals and unlabelled axons suggested a synaptic relationship. Such a relation was found in a relatively small proportion (2–3%) of the appositions studied. These specializations were always observed in close relation to an output synapse of the postsynaptic axon. It is suggested that the axo-axonal contacts described may provide an effective modulation of the synaptic transmission from axons in the lamprey spinal cord. © 1993 Wiley-Liss, Inc.     

The action of 5-HT on calcium-dependent potassium channels and on the spinal locomotor network in lamprey is mediated by 5-HT1A-like receptors

5-HT has a powerful modulatory action on the firing properties of single neurons as well as on locomotor activity. In lamprey, 5-HT increases the neuronal firing frequency in spinal neurons by reducing the conductance in Ca²⁺-dependent K⁺ channels (K_Ca) underlying the slow afterhyperpolarization (sAHP), and it also lowers burst frequency of the spinal locomotor network. To elucidate which type of 5-HT receptor mediates these effects, different specific receptor agonists and antagonists were applied during intracellular current lamp recordings and during NMDA-induced fictive locomotion in the lamprey spinal cord in vitro preparation. The 5-HT_1A receptor agonist 8-OH-DPAT ((±)-8-hydroxy-dipropylaminotetralin hydrobromide), the 5-HT₁ receptor agonist 5-CT (5-car☐yamidotryptamine maleate) and the 5-HT₂ receptor agonist α-CH₃-5-HT (α-methylserotonin maleate) all reproduced the actions of 5-HT at both the cellular and the network levels. The effects of all agonists were completely or partially blocked by the 5-HT_1A and 5-HT₂ receptor antagonist spiperone (spiroperidol hydrochloride) while selective 5-HT₂ receptor antagonists were ineffective. The selective 5-HT_1A receptor antagonist S(−)-UH301 (S(−)-5-fluoro-8-hydroxy-dipropylaminotetralin hydrochloride) also counteracted the effect of 5-HT on the sAHP. 5-HT₃ and 5-HT₄ receptor agonists and antagonists were without effects. The intracellular coupling mechanism was not sensitive to pertussis toxin nor to the cAMP dependent protein kinase blocker (Rp)-cAMPS. These results indicate that the intracellular coupling mechanism is not likely to be due to a down regulation of adenylate cyclase activity or through a direct modulation of K⁺ channels, as is common for 5-HT₁ receptors. The present results taken together with previous data indicates that the receptor responsible for the effects of 5-HT on the sAHP, and on the locomotor pattern generator in lamprey shares certain features, but is not identical to the mammalian 5-HT_1A receptor.     

Maturation-related changes in tolerance development to hexobarbital after short term treatment with diazepam in the rat

Male rats at six different ages received diazepam on a 4-day treatment schedule. Cross-tolerance to hexobarbital was tested several times during withdrawal period with an anaesthesia threshold technique. Pattern of cross-tolerance was different at different ages. Thus, age and maturation of the rat is a variable which must be considered in studies of tolerance to diazepam.     

Tolerance to Hexobarbital Induced by Short-Term Treatments with Diazepam and Tested with an EEG-Threshold Test in Male Rats

Abstract: Male Mol: SPRD rats were treated with 5 or 20 mg/kg of diazepam for 4 days. The treatment was repeated at two different ages. Diazepam was either dissolved in Intralipid^® (KABI, Sweden) or dispersed in gummi arabicum. Tolerance induced by the treatment was tested with an EEG-threshold technique where hexobarbital was infused intravenously on day 1, 4, 7 and 14 of the abstinence. The threshold was the dose of hexobarbital needed to induce a burst suppression of 1 sec. or more (silent second). After the first diazepam treatment significant increase in the hexobarbital threshold doses were recorded in all but one of the diazepam treated groups. The pattern varied depending on dose, age and solvent. After the second treatment tolerance was seen only when diazepam had been dissolved in Intralipid^®. Short term treatment with diazepam can induce crosstolerance to hexobarbital which probably is due to an increased excitation (physical dependence) in abstinence after treatment with diazepam.     

Influence of phenobarbital pretreatment on thein vitro ring a reduction of Δ4-3-oxo-steroids in rat liver microsomes

Summary The metabolism of 4-androstene-3,17-dione has been studied in rat liver microsomes. Treatment of the animals with repeated doses of phenobarbitalin vivo caused an enhanced rate of formation of 5-androstane-3,17-dione and of polar metabolites from this steroid. On the other hand, no significant increase was found in the 5-reductase activity present in the soluble cytoplasm after phenobarbital administration to the rats. Carbon monoxide and oxidized cytochrome c abolished the formation of polar metabolites from 4-androstene-3,17-dione but did not inhibit the 5-reductase activity. The present findings indicate that the hydroxylation and 5-reduction reactions, although both stimulated by phenobarbital treatment of the animals, do not involve common enzyme components.Supported by grants from the Swedisch Cancer Society, Swedish Medical Research Council (Project no. 13X-2525) and from Caroline Andriette Nobel's foundations for experimental medical research.     

Influence of Serum Protein Binding on the Pharmacokinetics of Quinidine in Normal and Anuric Rats

Abstract The pharmacokinetics of quinidine were investigated in normal and anuric rats after intravenous injection (25 mg per kg b. wt.). In normal rats only 2.6 percent of the injected dose was excreted as unchanged quinidine in the urine. Quinidine concentrations were determined in the blood and in different tissues after injection, and the serum protein binding was measured. Results were applied to a one compartment model. In normal rats a total body clearance of 18.5 ml/min. and a renal clearance of 0.5 ml/min. was found. The residual non-renal clearance (18.0 ml/min.), presumably taking place in the liver, exceeds the estimated liver blood flow (16.8 ml/min.), indicating efficient extraction of quinidine from plasma and blood cells (non-restrictive elimination). The apparent volume of distribution was greatly reduced, biological half-life slightly longer and the body clearance greatly reduced in anuric as compared to normal rats. The fraction of unbound quinidine in serum was 30.6 ± 0.6 (n=23) and 16.7 ± 0.5) (n=23) percent in normal and anuric rats. The reduction in the apparent volume of distribution is mainly explained by increased serum binding. The decline of body clearance of quinidine is most likely caused by a decreased liver blood flow in this complex state of renal insufficiency.