The shaping of pharyngeal cartilages during early development of the zebrafish

In zebrafish the cartilages of the pharynx develop during late embryogenesis and grow extensively in the larva before eventually being replaced by bone. Here we examine chondrocyte arrangements, shapes, numbers, and divisions in the young hyoid cartilages. We observe two distinct developmental phases, morphogenesis and growth. The first phase generates stereotypically oriented chondrocyte stacks that might form by intercalations among cells within the precartilage condensations. In mutants that have deformed cartilages the orientation of the stacks is changed, and we propose that their correct formation underlies the correct initial shaping of the organ. The following period of rapid, nearly isometric cartilage growth occurs by divisions of chondrocytes that are largely located near the joints, and appears to be under quite separate regulation.     

Insulin and insulin-like growth factor-I receptor mediated differentiation of 3T3-F442A cells into adipocytes: effect of PI 3-kinase inhibition

Sperm-zona pellucida binding, a crucial step in the process of fertilization, takes place in vivo in the upper portion of the fallopian tube. The presence of GnRH-like peptides in the female and the male genital tract has been described. In this work, the effect of GnRH and related peptides upon sperm-zona pellucida binding ability was studied. Sperm aliquots, capacitated for 4.5 h, were incubated for 5 min with saline (control) or 20 nM of GnRH, C-terminal (1-5) or N-terminal (5-10) fragments of GnRH, Substance P, dynorphin, bombesin, or mixed GnRH (a synthetic peptide with the same amino acids as GnRH but in different order). Sperm were also incubated with the GnRH antagonist Ac-3,4-dehydro-Pro1, -p-fluoro-D-Phe2, D-Trp3,6-LHRH, alone or before adding GnRH. The sperm were then tested using the hemizona assay. After 10 min, the number of zona-bound sperm was determined. In addition, the effect of GnRH upon the acrosome reactions, sperm movement characteristics, and sperm-zona collisions was evaluated. Sperm treated with GnRH bound in higher numbers to the zona than did control sperm (p < 0.005). The GnRH fragments, the GnRH antagonist, and related peptides did not have any effect on sperm-zona interaction; however, the GnRH antagonist totally blocked the stimulatory effect of GnRH. GnRH did not affect the percentage of acrosome-reacted sperm, pattern of sperm movement, or frequency of sperm-zona collisions. I suggest that the increased ability of the sperm to bind to the zona may be due to exposure and/or change of affinity of zona receptors on the sperm plasma membrane.     

Conduction properties of the crista terminalis in patients with typical atrial flutter: basis for a line of block in the reentrant circuit

INTRODUCTION: Previous mapping studies in patients with typical atrial flutter have demonstrated the crista terminalis to be a posterior barrier of the reentrant circuit forming a line of block. However, the functional role of the crista terminalis in patients with or without a history of atrial flutter is not well known. The aim of this study was to determine whether the conduction properties of the crista terminalis are different between patients with and those without a history of atrial flutter. METHODS AND RESULTS: The study population consisted of 12 patients with clinically documented atrial flutter (group 1) and 12 patients with paroxysmal supraventricular tachycardia as well as induced atrial flutter (group 2). A 7-French, 20-pole, deflectable Halo catheter was positioned around the tricuspid annulus. A 7-French, 20-pole Crista catheter was placed along the crista terminalis identified by the recording of double potentials with opposite activation sequences during typical atrial flutter. After sinus rhythm was restored, pacing from the low posterior right atrium near the crista terminalis was performed at multiple cycle length to 2:1 atrial capture. No double potentials were recorded along the crista terminalis during sinus rhythm in both groups. In group 1, the longest pacing cycle length that resulted in a line of block with double potentials along the crista terminalis was 638 +/- 119 msec. After infusion of propranolol, it was prolonged to 832 +/- 93 msec without change of the interdeflection intervals of double potentials. In group 2, the longest pacing cycle length that resulted in a line of block with double potentials along the crista terminalis was 214 +/- 23 msec. After infusion of procainamide, it was prolonged to 306 +/- 36 msec with increase of interdeflection interval of double potentials. CONCLUSION: The crista terminalis forms a line of transverse conduction block during typical atrial flutter. Poor transverse conduction property in the crista terminalis may be the requisite substrate for clinical occurrence of typical atrial flutter.     

Physiological and histological characterisation of a pig kidney in vitro perfusion model for xenotransplantation studies

A pig kidney perfusion model aimed for use in immunological and physiological xenotransplantation research has been developed. Organ viability was characterised by clearance studies, functional response to hormones/diureticum and by light microscopical examination. The pig kidney was perfused in a specially designed plexiglass chamber, using a roller pump and a small membrane oxygenator (O2/CO2, 95/5). The recirculating perfusate used was autologous pig blood diluted by Tyrodes solution to a hematocrit of 30%, at a total starting volume of 600-650 ml. The temperature was 37 degrees C. It was crucial for good organ function that the nephrectomy operating time, as well as the warm (1-2 min) and cold ischemia (average 43 min) times were minimized. The average total perfusion time was 151 minutes. Physiological parameters were measured during 10-15 minute periods at average times of 40, 63, 88 and 142 minutes. The clearance values of inulin in these periods were 54 +/- 13, 59 +/- 15, 48 +/- 23, 27 +/- 5 and for PAH; 103 +/- 14, 121 +/- 14, 106 +/- 30, 114 +/- 34 ml/min/100 g tissue weight. The plasma flows were 123 +/- 12, 155 +/- 17, 136 +/- 36 and 206 +/- 57 ml/min/100 g. The injection of 0.5 micrograms of alpha ANP to the perfusate resulted in a significant decrease in vascular resistance, and increase in urine production (+107%), as well as sodium (+112%) and potassium (+46%) excretion. Ten mg furosemide doubled the urine production and sodium excretion, while potassium excretion increased marginally. The number of leucocytes decreased by 39% during the perfusion, while the platelet count was unaffected. Light microscopy of the renal tissue after termination of the experiments revealed endothelial damage to variable extent. Loss of endothelial cells was most obvious at the level of arcuate and interlobular arteries, while the endothelium was intact in larger arteries and veins. Accumulation of polymorphonuclear granulocytes was found predominantly in the peritubular vessels, and to a lesser degree in the cortical venules. In the tubular cells, only minimal epithelial swelling and irregular cytoplasmic vacuolisation was found. Thus, a good functional viability can be maintained during 2 hours in vitro perfusion, although a decline in function as well as structural damage can be seen at the end of the experiment.     

Expression of dentin sialoprotein (DSP) and other molecular determinants by a new cell line from dental papillae, MDPC-23

The purpose of this study was to characterize the molecular expression of a spontaneously immortalized and cloned cell line (MDPC-23) derived from 18-19 day CD-I fetal mouse molar dental papillae to determine if these cells were odontoblast-like. Western blots showed that a protein band, at approximately 105 kDa, reacting positively with anti-DSP antibodies and co-migrating with mouse DSP, was present in lysates of cells from passages 7, 37 and 77, in serum-free conditioned medium from passage 37 cells, and in mouse dentin extract. A minor band at 55 kDa was also apparent in cell lysates. Using a cDNA probe for a 486bp mouse DSP coding sequence, DSP or DSP-PP mRNA expression was detected by Northern analysis as well as Southern analysis after RT-PCR in all three passages. It was also shown that in these cells 1,25 (OH)2 vitamin D3 upregulated both osteopontin and osteocalcin mRNA, and dexamethasone downregulated alkaline phosphatase and alpha2(I) collagen mRNA. Thus, MDPC-23 cells express proteins which are common to mineralizing tissue. The expression of DSP and DSP-PP strongly suggests that this cell line is from the odontoblast lineage.     

X-linked female band heterotopia-male lissencephaly syndrome

OBJECTIVE: The purpose of this study was to determine if a small pneumothorax would influence the pleurodesis resulting from talc instillation. METHODS: Sixty rabbits received an intrapleural injection of 400 mg/kg talc slurry. One half also received 10 mL of air intrapleurally after the talc. Ten rabbits in each group were killed 2, 14, and 28 days after instillation. RESULTS: Two days after the injection, the mean volume of air in the animals that had received the air was 7.5+/-0.4 mL. There was no air present in any other rabbits. The volume of pleural fluid and the pleural fluid glucose, protein, cell count, and differential were similar in both groups on day 2, while the LDH level was significantly higher in the air group (p<0.05). The degree of gross adhesions and microscopic fibrosis was similar in both groups and increased with time. CONCLUSIONS: A small pneumothorax does not decrease the efficacy of talc pleurodesis in our experimental model. These results suggest that the presence of a small amount of intrapleural air is not a contraindication to talc pleurodesis in humans.     

Blocking filter vents increases carbon monoxide levels from ultralight, but not light cigarettes

Effect of vent blocking on carbon monoxide (CO) exposure from a best-selling light cigarette was examined in 12 daily cigarette smokers. Mean CO boosts were not different from each other with (a) 0% filter vents blocked (5.0 ppm), (b) vents covered with lips (4.9 ppm), (c) 50% of vents covered with tape (4.8 ppm), and (d) vents covered with a pinch of the fingertips (4.9 ppm). A second study in another 12 smokers was conducted to replicate these findings as well as earlier findings that blocking vents doubles CO intake from 1-mg tar cigarettes. While blocking half the vents with fingers significantly increased CO boost from ultralight cigarettes (2.8 vs. 5.4 ppm, p < 0.001), it did not influence boosts from light cigarettes (6.3 vs. 6.5 ppm, p = 0.8). The lowest yield cigarettes (1 mg tar) may be special. Smoking machine simulations provide poor models of human smoke intake. It is unclear whether tar and nicotine intake from light cigarettes was influenced by vent blocking.     

Exhaled breath condensate isoprostanes are elevated in patients with acute lung injury or ARDS

BACKGROUND: Oxidant stress is a purported mechanism of tissue damage in patients with ARDS and acute lung injury (ALI). Isoprostanes, prostanoid compounds primarily formed nonenzymatically via lipid peroxidation, are precise markers of in vivo oxidant stress. Plasma levels of metabolites of 8-iso-prostaglandin-F2alpha (8-iso-PGF2alpha) correlate with outcome in patients with ARDS. OBJECTIVE: To examine exhaled breath condensate levels of 8-iso-PGF2alpha as a noninvasive quantification of pulmonary oxidant stress in patients with, or at risk for, ARDS/ALI. METHODS: Breath condensate was collected from 22 patients with, or at risk for, ARDS/ALI by placing Tygon tubing submerged in an ice bath in line with the expiratory limb of the ventilator circuit. Ten patients without lung disease, who were intubated while undergoing minor surgical procedures, served as control subjects. Between 1 and 3 mL of condensate was collected over a 30- to 60-min period, then immediately frozen and stored at -70 degrees C until analysis. The 8-iso-PGF2alpha was purified and derivatized, then quantified by stable isotope dilution in conjunction with gas chromatography/mass spectrometry. RESULTS: The mean level of exhaled 8-iso-PGF2alpha in the patients with ALI/ARDS, 87+/-28 pg/mL, was significantly higher than the mean in the normal group, 7+/-4 pg/mL (p = 0.007). The 8-iso-PGF2alpha levels were greater than two standard deviations above the mean of the normal group in 12 of 22 patients with or at risk for ARDS/ALI. CONCLUSIONS: These results provide further evidence that lipid peroxidation does occur in patients with ARDS/ALI. The measurement of exhaled isoprostanes provides a novel, noninvasive method to quantify oxidant stress in such patients.     

Fracture-dislocation of the lunotriquetral coalition

Bony fusions involving the carpus have a much higher prevalence in blacks relative to whites. This article describes a case of lunotriquetral coalition fracture-dislocation in an African American. This lesion is best treated through open reduction and pin fixation.     

Variability of clinical and pressure-flow study variables after 6 months of watchful waiting in patients with lower urinary tract symptoms and benign prostatic enlargement

PURPOSE: We quantified the physiological variability of clinical and pressure-flow study variables in patients with symptomatic benign prostatic enlargement. MATERIALS AND METHODS: Symptom scores were measured, and advanced urodynamic studies with pressure-flow analysis were performed in 178 patients before and 6 months after a period a watchful waiting. RESULTS: Patients without bladder outlet obstruction experienced significant symptomatic improvement. Symptoms in patients with obvious bladder outlet obstruction did not improve significantly. The reproducibility of mean pressure-flow variables was evident. However, there was an important intra-individual variability. Patients with obvious bladder outlet obstruction showed a significant decreases in detrusor pressure at maximal flow of 14cm. water, a significant decrease in the urethral resistance factor of 7 cm. water and a significant decrease of 1 obstruction class on the linear passive urethral resistance relation nomogram, indicating less severe bladder outlet obstruction. CONCLUSIONS: Mean differences among therapy groups must be regarded critically, especially when the difference are slight and possibly within physiological variability.