INTRAUTERINE CANDIDA INFECTION IN PREMATURE BABY

An autopsy case of pulmonary candidiasis occurring in a neonatal girl was reported. The mycological examination of the lung taken at autopsy revealed only Candida albicans and followed by the elucidation under the microscopic sections prepared with special stains; periodic acid-Schiff and methenamine silver, in the lung, stomach, umbilical cord, and amnion. The presence of Candida vaginitis in her mother supported the concept that Candida albicans was the etiological agent of the pulmonary candidiasis.     

Pathogenesis of Rinderpest Virus Infection in Rabbits I. Clinical Signs, Immune Response, Histological Changes, and Virus Growth Patterns

Rabbits were intravenously inoculated with an attenuated rinderpest virus (L strain), and general patterns of the disease were investigated. The rabbits developed fever with concomitant occurrence of diarrhea and lymphopenia. Early production of interferon was followed by a rise of neutralizing antibody. Histological examinations revealed an involvement of all of the lymphoid tissues, with primary lesions consisting of necrosis of the lymphoid follicles and formation of giant cells. Immunofluorescent examinations suggested that the virus growth was present in almost all of the lymphoid tissues. The possibility of application of this experimental system for the study of systemic infection by measles virus was discussed.     

C to T transition at the first nucleotide of codon 63 of the β-globin gene corresponding to hemoglobin M-Saskatoon in an Indonesian boy

Summary Hemoglobin (Hb) M-Saskatoon, a variant of methemoglobin, is characterized by mild hemolysis. It is caused by the substitution of a histidine by a tyrosine at the 63rd amino acid residue of the -globin chain. Amplification and sequence analysis of genomic -globin DNA from an Indonesian boy diagnosed as having the more severe disease thalasemia demonstrated the presence of a C to T transition at nucleotide 473 in one of the two -blogin genes resulting in a histidine to tyrosine substitution at 63rd residue. This amino acid change matched with that reported in Hb M-Saskatoon. This nucleotide change abolished a recognition site for the restriction endonucleaseNlaIII.NalIII digestion of the corresponding -globin DNA amplified from the patient's parents indicated that the mutation was inherited through from his mother. This result shows that the world-wide distribution of Hb M-Saskatoon extends to Indonesia, where it was not previously identified. Possible causes of the unusually severe symptoms observed in the case are discussed.     

Effect of solvent evaporation rate on microphase-separated structure of segmented poly(urethane-urea) prepared by solution casting

A useful instrument for polymer film preparation by solution casting was employed in this study. It enabled us to control the solvent evaporation rate of the polymer solution. By using this instrument, the aggregation of hard segments in segmented poly(urethane-urea) (SPUU) was investigated. SPUU was prepared from poly(tetramethy1ene oxide), 4,4′-diphenylmethane diisocyanate and ethylenediamine. The effect of solvent evaporation rate on the microphase-separated structure of SPUU was elucidated by dynamic mechanical analysis, tensile test, differential scanning calorimetry analysis, small-angle X-ray scattering measurement, IR and IR dichroism analyses. The aggregation of hard segments in SPUU was observed to be affected considerably by the solvent evaporation rate of the cast film during the preparation. It was found that the slower the solvent evaporation rate, the higher the aggregation of hard segments to form rigid hard segment domains in SPUU. Nine months after casting, this casting effect still remained on the aggregation state of hard segments of SPUU films, although the interdomain spacing was not influenced by its rate.     

The cyclo-copolymerization of diallyl compounds and sulfur dioxide, 6. 1,6-Heptadiene and sulfur dioxide

Copolymers from 1,6-heptadiene ( 1 ) and SO₂ with various mole ratios of their units were prepared. Their structures were studied by elemental analyses, IR and ¹H NMR spectroscopy. Structures containing a cyclopentane ring ( 2 ) and such containing a thiane ring ( 3 ) in the main chain are proposed.     

Immature dendritic cells (CD11c+ CD3- B220- cells) present in mouse peripheral blood

It is well known that dendritic cells (DCs) are developed from the peripheral blood of mice when peripheral blood mononuclear cells (PBMCs) are cultured with GM-CSF. We have previously found that immature DCs are present in the blood even in humans. In the present study, we show that CD11c+ CD3- B220- cells in the mouse peripheral blood are immature DCs. The percentage of CD11c+ CD3- B220- cells in the (PBMCs) of normal mice ranges from 0.5 to 2.5%. The CD11c+ CD3- B220- cells in the PBMCs show dendrites, similar in shape to the CD11c+ CD3- B220- cells in the spleen, which are thought to be DCs definitely. However, they have practically no capacity to stimulate the proliferation of allogeneic T cells, and show a lower expression of MHC class II, B7-1 and B7-2 than CD11c+ CD3- B220- cells in the spleen. When the CD11c+ CD3- B220- cells in the PBMCs are cultured with GM-CSF, they show not only the potent ability to stimulate the proliferation of allogeneic T cells but also a higher expression of MHC class II, B7-1 and B7-2. Moreover, they migrate into the spleen when they are injected intravenously. These results suggest that CD11c+ CD3- B220- cells in the PBMCs are immature DCs, and that they migrate into the spleen, where they mature.     

Background conductance attributable to spontaneous opening of muscarinic K+ channels in rabbit sino-atrial node cells.

Single myocytes were dissociated from the rabbit sino-atrial node, and the membrane background conductance produced by spontaneous opening of the muscarinic K+ channels was investigated by recording whole-cell and single channel currents in both normal K+ (5.4 mM) and high-K+ (145 mM) external solutions. Increasing external K+ concentration ([K+]o) from 5.4 to 145 mM induced a large inward shift of the whole-cell current accompanied by considerable current fluctuations at -50 mV. The high-K(+)-induced current was both K+ selective and voltage dependent, which was examined by varying [K+]o. This current was almost completely suppressed by 1-5 mM Ba2+ or 2-10 mM Cs+ and it was partly blocked by 10 microM atropine. In high-K+ (145 mM) solution, 20 nM acetylcholine (ACh) further increased the K+ conductance as well as the current noise. The power density spectrum of the noise was fitted with a sum of two Lorentzian functions. The corner frequencies of both the slow (approximately 5 Hz) and fast (approximately 120 Hz) components were comparable between the noise before and during the ACh application. Internal dialysis with a non-hydrolysable derivative of ATP, 5'-adenylylimido-diphosphate (AMP-PNP) or Mg(2+)-free solution markedly decreased both the amplitude and fluctuations of the high-K(+)-induced current. The relation between the variance of the current fluctuations and the mean current amplitude was linear in every experiment using dialysis of AMP-PNP or Mg(2+)-free internal solution, or using superfusion of ACh. The slopes of these relations gave comparable single channel current amplitudes of -0.7 pA at -50 mV. These results indicate that the spontaneous opening of the muscarinic K+ channels is largely responsible for the high-K(+)-induced current. In the high-K+ solution, the variance-mean relation at -50 mV showed that the muscarinic K+ channel provides an inward current of 3.12 +/- 2.13 pA pF-1 (n = 23), which was about 60% of the total inward background current. In the normal K+ solution, the variance-mean relation at -50 mV indicated that an outward current of 6.0 +/- 2.0 pA (0.33 +/- 0.28 pA pF-1, n = 8) was provided by the K+ channel. The single channel current amplitude was estimated to be 0.06 +/- 0.02 pA (n = 9). Cell-attached recordings in the absence of ACh demonstrated sporadic and brief openings of channels identical to the ACh-induced channels. The power density spectra of the single channel currents exhibited kinetic properties comparable with those of the whole-cell currents.(ABSTRACT TRUNCATED AT 400 WORDS)     

Synthesis and characterization of poly(1-benzoylthiosemicarbazide) and poly(1,3,4-thiadiazole amine) from 2-(p-aminophenyl)-1,3,4-oxadiazoline-5-thione via ring-opening process

A novel thermally stable and semiconducting polyheterocycle, poly(1,3,4-thiadiazole amine), was synthesized from 2-(p-aminophenyl)-1,3,4-oxadiazoline-5-thione via ring-opening. The polymer is a new class of ordered alternating copoly(aniline) containing 1,3,4-thiadiazole heterocyclic units. An investigation of the reaction of 2-phenyl-1,3,4-oxadiazoline-5-thione with aniline was conducted as a model reaction for the polymerization, and poly(phosphoric acid) (PPA) and phosphorus pentoxide/methanesulfonic acid (PPMA) were found to be favorable both as condensing agent and solvent for the formation of 2-anilino-5-phenyl-1,3,4-thiadiazole as a model compound. The polymerization was carried out both by two-step procedure that included ring-opening self-polyaddition giving poly(1-benzoylthiosemicarbazide), followed by cyclodehydration to poly(1,3,4-thiadiazole amine), and by a one-step procedure including cyclodehydration in situ. The poly(1-benzoylthiosemicarbazide) which was formed in the first step in m-cresol had reduced viscosities up to 0,42 dL·g^?1, and it was converted to poly(1,3,4-thiadiazole amine) by treating in PPA or PPMA. Poly(1,3,4-thiadiazole amine) having reduced viscosities up to 0,25 dL·g^?1 was also synthesized by the direct one-step polymerization in PPA or PPMA. The polymer is highly thermally stable and exhibited no weight loss up to 350°C under nitrogen. Its electric conductivity was less than 10^?10 S·cm^?1 at ambient temperature, but markedly increased to 2,9·10^?7 S·cm^?1 upon doping with iodine.     

Fast and slow blockades of the inward-rectifier K+ channel by external divalent cations in guinea-pig cardiac myocytes

The present patch-clamp study shows that external Mg²⁺, Ca²⁺ and Sr²⁺ decrease the unit amplitude of inward current through the inward-rectifier K⁺ channel in a concentration-dependent manner. Sr²⁺ produces a voltage-dependent flickering block as well, and the fractional electrical distance between the external orifice and the Sr²⁺ binding site () is 0.73. The decrease of unit amplitude is reversible and voltage independent while it does not increase the noise level on the open-channel current. Unit current decreased by Mg²⁺ or Ca²⁺ has a longer mean open time, which is inversely proportional to the unit amplitude. External Mg²⁺ does not decrease the amplitude of unit outward current. A surface potential shift, measured using voltage-dependent Cs⁺ block (=1.60), failed to explain the current decrease. Therefore, we conclude that (1) the external divalent cations cause an extremely fast channel block, which appears as a decreased amplitude of the unit current on the recording system; (2) the blocking site (fast site) is present near the external orifice of the channel, and it is separate from the blocking site (slow site) to which Cs⁺ and Sr²⁺ bind.     

The effect of external potassium on the elementary conductance of the ACh-induced potassium channel in the sino-atrial node

The mechanism underlying the increase in the potassium conductance of the acetylcholine (ACh)-induced channel on increasing the extracellular potassium concentration (|K|₀) was studied. The relaxation as well as the current fluctuations of the drug-induced current were measured at 3 and 12 mM |K|₀ by conducting voltage clamp experiments in the rabbit sinoatrial node. The following results were obtained:

1. The time constant of relaxation (τ_relax) was not affected by changing |K|₀. In both cases τ_relax was about 130 ms at ?80 mV, 100 ms at ?40 mV and 60 ms at + 20 mV. It is, therefore, unlikely that the increase of the ACh-induced potassium conductance is due to a longer average open time of the drug-operated potassium channels.
2. The chord conductance of the ACh-induced K current was increased by a factor of 1.7 at ?40 mV and by 1.5 at +10 mV on elevation of |K|₀ from 3 to 12 mM.
3. From the relation between the variance of the current fluctuations and the mean amplitude of the current the single channel conductance was determined to be 3.3 pS at 3 mM |K|₀ and 5.9 pS at 12 mM |K|₀, thus γ was increased by a factor of 1.7.
4. From the power density spectrum an increase in the single channel conductance by a factor of 1.8 (at ?40 mV) could be calculated. The corner frequency was not affected.
5. The increase in the potassium conductance, expected from the constant field equation when |K|₀ is increased, agrees well with the experimental results.