Guanidinium-based potentiometric SO2 gas sensor

An SO2 gas sensor was developed by using a hydrogen sulfite-selective electrode positioned behind a gas-permeable membrane (GPM). The hydrogen sulfite-selective electrode was prepared by incorporating a multicyclic guanidinium ionophore in a plasticized poly(vinyl chloride) membrane. This gas sensor presents important advantages over the conventional Severinghaus-type SO2 gas sensor that contains a pH electrode immersed in an internal solution behind the GPM. The Severinghaus gas sensor suffers interferences from weak acids that can cross the GPM as gases and change the pH of the internal solution. In contrast, in the proposed sensor, the excellent selectivity of the HSO3- electrode and the ability of the GPM to discriminate gaseous from nongaseous species combine to generate the most selective potentiometric SO2 gas sensor reported to date.     

Mapping the gene causing hereditary primary hyperparathyroidism in a Portuguese kindred to chromosome 1q22-q31

A Portuguese kindred with autosomal dominant isolated primary hyperparathyroidism (HPT) that was associated with parathyroid adenomas and carcinomas was investigated with the aim of determining the chromosomal location of this gene, designated HPTPort. Leukocyte DNA from 9 affected and 16 unaffected members and 7 parathyroid tumors from 4 patients was used in comparative genomic hybridization (CGH), tumor loss of heterozygosity (LOH), and family linkage studies. The CGH studies revealed abnormalities of chromosomes 1 and 13, and the results of LOH studies were consistent with the involvements of tumor suppressor genes from these regions. Family segregation studies mapped HPTPort to chromosome 1q22-q31 by establishing linkage with eight loci (D1S254, D1S222, D1S202, D1S238, D1S428, D1S2877, D1S422, and D1S412) (peak two-point LOD scores = 3. 46-5.14 at 0% recombination), and defined the location of HPT Port to a 21 cM region flanked centromerically by D1S215 and telomerically by D1S306. Thus, HPTPort has been mapped to chromosome 1q22-q31, and a characterization of this gene will help to elucidate further the mechanisms that are involved in the development of parathyroid tumors.     

Cellular receptors for sex steroids in human pituitary adenomas

Cellular receptors for sex steroids (SSRs) were studied in an unselected series of 55 human pituitary tumors. Cytosolic receptors for estrogen (ERcs) and progesterone (PgRcs) were determined in all cases and cytosolic androgen receptors (ARcs) in 47 cases. Nuclear receptors (ERns, PgRns, ARns) were also studied in 33 cases. ERs and PgRs were determined by an ELISA and ARs by [3H]methyltrienolone binding. Where both cytosolic and nuclear receptors were studied (n = 33), ERs, PgRs and ARs were found in at least one subcellular fraction in 66.7, 60.6 and 81.8% of cases respectively, ERs and ARs being mainly recovered from the cytosol and PgRs from the nucleus. No linear correlation was found between pre-operative plasma steroid hormones and their specific cellular receptors. Nonetheless, the differential expression of SSRs according to sex and gonadal status at the time of surgery strongly supports their regulation by the steroid environment in vivo: PgRcs were more frequent in tumors found in women (41.4 vs 15.4%, P < 0.05), whereas a high expression of ERcs and ARcs (> 15 fmol/mg protein) was more common in tumors found in men (34.5 vs 10.3%, P < 0.05 and 54.5 vs 24.0% respectively). PgRs were positively correlated with ERns, indicating the possibility of estrogen priming of their expression, and negatively correlated with ARs in nuclear fractions. SSRs appeared to be widely distributed among pituitary tumors, although, compared with other hormone-secreting groups, prolactinomas displayed a higher ERc expression (34.8 +/- 11.3 vs 4.8 +/- 5.1 fmol/mg protein, P = 0.007) and gonadotroph cell adenomas lower ARc values (1.3 +/- 0.8 vs 38.2 +/- 10.6 fmol/mg protein, P = 0.048). Microadenomas were characterized by a higher PgR expression than macroadenomas, whereas hemorrhagic (macro)adenomas were characterized by a high ER expression (> 90%). The present results indicate that most pituitary tumors are targets for sex steroids, SSR expression being partially triggered by the steroid environment itself. Possible physiopathological and therapeutic implications of these findings are discussed.     

The development of perceptual completion abilities: infants' perception of stationary, partially occluded objects

We explored infants' ability to perceive stationary, partially occluded objects as connected units (Experiments 1 and 2) with specific appearances (Experiment 3). In each experiment, the infants saw 2 test events involving what appeared to adults to be a tall rectangular object whose middle portion was hidden behind a narrow screen. During the test events, the screen alternately uncovered and covered the object. In Experiments 1 and 2, removal of the screen revealed either a single, connected rectangle (complete object event) or an interrupted rectangle with a gap where the screen had been (broken object event). In Experiment 3, removal of the screen revealed either a rectangle (rectangle event) or a cross-shaped object (cross-shape event). The pattern of infants' looking times at these events suggest that they perceive the unity of the partially occluded object by 6.5 months of age but did not perceive the form of the hidden part of the object until 8 months. The results of baseline control conditions support this interpretation.     

Effect of perilymphatic fistulas on evoked otoacoustic emissions in the guinea pig

Round window perilymphatic fistulas were surgically created in 20 guinea pigs. Distortion product otoacoustic emissions (DPOAEs) at 2fl - f2 were recorded prior to and immediately following laceration of the round window. The stimuli were equal level sinusoids (f1 < f2) with f2 ranging from 2 to 10 kHz, a fixed f2:f1 ratio of 1.25, and stimulus levels (L2 = L1) ranging from 20 to 80 dB SPL. After an 18-day survival period, emission measurements were repeated, and fluorescein was infused into the cerebrospinal fluid to verify patency or closure of the fistula. Nine animals demonstrated patent fistulas, whereas 11 had closed fistulas. There was a statistically significant reduction in DPOAE amplitude after an acute fistula across all stimulus levels (p < .001). At 18 days the DPOAE amplitudes in animals with healed fistulas could not be differentiated from controls, whereas DPOAE amplitudes in animals with patent fistulas were statistically different from controls (p < .05). The results suggest that evoked otoacoustic emissions may be useful in detecting perilymphatic fistulas.     

The biological properties of Aerococcus antagonists, representatives of human microbiocenoses

The paper deals with the data on biology of Aerococcus, a slightly studied group of microorganisms. Physiological-biochemical properties of Aerococcus are described, data of their distribution in nature are given. Peculiar attention is paid to the estimate of the role of Aerococcus in human microbiocenoses. As a result of the profound and all-round study of this group of microorganisms the authors have developed new bacterial drug "A-bakterin" based on the aerococcus strain. Data presented about the results of clinical tests of "A-bakterin" are presented, a possibility to use Aerococcus lysate in the elaboration of new drugs is discussed.