All-trans retinoic acid stimulates growth and extracellular matrix production in growth-inhibited cultured human skin fibroblasts

All-trans retinoic acid was examined for effects on human dermal fibroblast proliferation and for effects on fibroblast production and expression of non-collagenous and collagenous components of the extracellular matrix in vitro. Fibroblast proliferation was blocked when the cells were cultured in the presence of a serum-free culture medium containing epidermal growth factor, hydrocortisone, insulin, ethanolamine, phosphoethanolamine, and bovine pituitary extract as growth supplements and 0.15 mM Ca++. This level of extracellular Ca++ is lower than that needed to support fibroblast growth. Under these conditions, growth was stimulated by all-trans retinoic acid. Proliferation was also stimulated in the same basal medium without the growth supplements. Growth-promoting concentrations of all-trans retinoic acid ranged from 0.5-2.0 micrograms/ml (1.7-6.6 X 10(-6) M). Stimulation of proliferation was not seen at higher or lower concentrations. Concentrations of all-trans retinoic acid that stimulated proliferation also induced increased production of fibronectin as indicated by biosynthetic labeling/immunoprecipitation and by enzyme-linked immunosorbent assay. Increased production was associated with increased staining for fibronectin in the extracellular matrix. Increased production of two other non-collagenous extracellular matrix component, i.e., thrombospondin and laminin, also occurred in all-trans retinoic acid-treated cells. At 0.5 micrograms/ml, all-trans retinoic acid also stimulated production of type I collagen by the dermal fibroblasts, but at higher concentrations (2.5 micrograms/ml) production of type I collagen was inhibited. These data indicate that all-trans retinoic acid can induce changes in dermal fibroblasts in vitro (i.e., increased proliferation and extracellular matrix production) that mimic the major changes seen in the dermis after topical treatment with this agent.

Recurrent mutation in the human phenylalanine hydroxylase gene

We report the identification of a missense mutation of Glu280 to Lys280 in the phenylalanine hydroxylase (PAH) gene of a phenylketonuria (PKU) patient in Denmark. The mutation is associated with haplotype 1 of the PAH gene in this population. This mutation has previously been found in North Africa, where it is in linkage disequilibrium with haplotype 38. While it is conceivable that this mutation could have been transferred from one haplotype background to another by a double crossover or gene conversion event, the fact that the mutation is exclusively associated with the two different haplotypes in the two distinct populations supports the hypothesis that these two PKU alleles are the result of recurrent mutations in the human PAH gene. Furthermore, since the site of mutation involves a CpG dinucleotide, they may represent hot spots for mutation in the human PAH locus.

Interstitial purine metabolites during regional myocardial ischemia

The purpose of this study was to determine the changes in cardiac interstitial fluid (ISF) purine metabolites during 90 min of regional myocardial ischemia. To collect ISF metabolites and measure local coronary blood flow (CBF), cardiac microdialysis probes were implanted into the left anterior descending artery (LAD) and left circumflex artery (LC) perfused myocardium of chloralose-urethane anesthetized dogs (n = 7). Regional ventricular wall thickness was measured in the LAD and LC perfused regions with sonomicrometric crystals, using systolic wall thickening (SWT) as an index of regional ventricular function. Regional myocardial ischemia, produced by occlusion of the LAD, resulted in a decrease in CBF (hydrogen clearance) from 77.3 +/- 12.4 to 10.9 +/- 4.4 ml/min/100 g (P less than 0.05), and systolic wall thinning (control SWT = 15.5 +/- 2.2%; ischemic SWT = -6.8 +/- 1.7%). ISF adenosine was transiently elevated in the ischemic region, obtaining a maximum sixfold increase after 15 min of ischemia. Inosine, hypoxanthine, and to a lesser extent xanthine, composed the majority of metabolites which accumulated in the ISF of the ischemic region, accounting for greater than 95% of the total purine metabolites in the ISF after 20 min of ischemia. Despite the marked increase in ISF inosine, hypoxanthine, and xanthine levels, ISF uric acid levels did not increase in the ischemic region. Although CBF and SWT did not change in the nonischemic LC perfused area, there were small transient increases (two- to fourfold) in ISF adenosine, inosine, and hypoxanthine levels. In summary, these data demonstrate that purine metabolites accumulate rapidly in the ISF during myocardial ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of oxygen-derived free radicals in superior mesenteric artery occlusion shock in rats

This study was designed to investigate effects of cellular injury mediated by oxygen-derived free radicals on the intestine, heart, liver, kidney and lung tissues during superior mesenteric artery occlusion shock in rats. The animals were divided into four groups: control (Group 1, n = 6), one hour occlusion (Group 2, n = 8), one hour after releasing the clamp (Group 3, n = 8), and two hours after releasing the clamp (Group 4, n = 8). Compared to control values, the contents of malondialdehyde (MDA) in each tissue in Group 2 had 110 significant changes (P greater than 0.05); in Group 3, MDA in the intestine and heart tissues significantly elevated by 62% (P less than 0.05) and 56% (P less than 0.05); in Group 4, MDA in the intestine, heart, liver, and lung tissues increased by 121% (P less than 0.01), 65% (P less than 0.05), 32% (P less than 0.05), and 31% (P less than 0.05), respectively. Plasma lactic acid, beta-glucuronidase and acid phosphatase increased significantly (P less than 0.01). The results showed that oxygen-derived free radical could cause lipid peroxidation damage not only in the intestine tissue, but also in the heart, liver, and lung tissues, suggesting that oxygen-derived free radicals might play an important role in cellular injury during superior mesenteric artery occlusion shock.

Breast tumor radioimmunodetection with a 111In-labeled monoclonal antibody (MA5) against a mucin-like antigen

Monoclonal antibody MA5 recognizes a determinant displayed on high molecular weight antigens associated with secretory and malignant breast epithelial cells. MA5 reactivity with greater than 95% of primary and metastatic breast tumors, surface expression of the antigen, as well as its ability to localize within breast tumor xenografts prompted this initial study to determine the efficacy of MA5 to localize breast tumors by radioimmunoscanning. A total of 17 patients was monitored, each receiving 2 mg of purified MA5 labeled with 5 mCi of 111In. Some patients also received 3 or 18 mg of unlabeled carrier antibody (MA5); no serious allergic reactions were noted. Primary tumors, bone lesions, soft tissue recurrences, and lung metastases greater than 3 cm in diameter were detectable, whereas only one lesion (hilar node) less than 3 cm was localized. Significant antibody accumulation was noted in the liver and less significant uptake in the spleen and bone. The extensive fibrosis and poor vascularization of breast tumors may partly explain the limited sensitivity obtained thus far. The imaging results obtained with MA5 are compared with other antibodies which we show recognize the same antigens.

Mechanism of angiotensin II action on proximal tubular transport

Our previous studies have shown that a low dose of angiotensin II (Ang II) stimulates fluid and bicarbonate absorption from the apical side of rat proximal tubule (PCT). These effects can be blocked by Ang II antagonist, (Sar1, Ile8)Ang II. The cellular mechanism underlying Ang II action, however, remained unclear. Thus, this study was designed to investigate the possible role of phosphoinositide turnover in mediating this action of angiotensin. Rat PCT was perfused in vivo with Ringer's solution containing [3H]inulin as a volume marker. Bicarbonate flux (JHCO3) was determined by total CO2 changes between the collected fluid and the original perfusate as analyzed by microcalorimetry. Luminal perfusion of 10(-11) M Ang II stimulated both JHCO3 and fluid reabsorption. These effects could be blocked by 10(-3) M amiloride and 10(-5) M ethylisopropylamiloride. Luminal perfusion of 4 beta-phorbol-12-myristate-13-acetate (10(-8) M) also stimulated both fluid reabsorption and JHCO3. These effects could also be blocked by amiloride and ethylisopropylamiloride. When both Ang II (10(-11) M) and 4 beta-phorbol-12-myristate-13-acetate (10(-8) M) were perfused together, the stimulatory effects on fluid reabsorption and JHCO3 were not additive. These results suggest that Ang II interacts with its receptors on the apical membrane leading to modulation of the Na-H exchange mechanism in PCT. The phosphoinositide turnover may play an important role in the Ang II action on PCT transport.

Cholinergic effect on rat proximal convoluted tubule

The effect of cholinergic agents on proximal tubular absorption of bicarbonate and fluid were examined to investigate the possible role of the cholinergic receptor in the regulation of renal function. Proximal convoluted tubule (PCT) and peritubular capillaries were perfused with bicarbonate-Ringer's solution containing radioactive inulin. Bicarbonate (total CO2) was determined by microcalorimetry. The rates of bicarbonate absorption (JHCO3) and fluid absorption (Jv) were 143.3 +/- 7.2 pEq/min.mm and 2.52 +/- 0.23 nl/min.mm, respectively. Addition of carbachol (10(-8) M) to the capillary perfusate reduced JHCO3 by 17% and Jv by 32%. A higher dose of carbachol (10(-6) M) did not further inhibit JHCO3 or Jv. Simultaneous perfusion of atropine (10(-5) M) together with carbachol (10(-8) M) abolished the inhibitory effect of carbachol on PCT transport. Atropine itself, however, had no effect on PCT transport. The inhibitory effect of carbachol was also diminished by lanthanum chloride (10(-4) M). Carbachol (10(-6) M) had no effects from the luminal side. W-7, a calmodulin antagonist, inhibited carbachol-induced effects. Ionophore A-23187 also inhibited Jv and JHCO3. However, there was no additive effect when A-23187 and carbachol were combined in the capillary perfusate. These results suggest that there are functional cholinergic receptors on the basolateral side of the PCT that can regulate JHCO3 and Jv. Calcium influx may play a role in mediating the cholinergic effects on PCT transport.

Concentration/response relations for the multiple antiarrhythmic actions of sotalol

Sotalol, one of the first beta-receptor antagonists synthesized, is a promising investigational agent with remarkable efficacy for treatment of patients with ventricular and supraventricular arrhythmias. Unlike other beta blockers, sotalol also possesses class III antiarrhythmic action, evidenced by prolongation of the myocardial action potential duration. This additional action probably accounts for the greater antiarrhythmic efficacy of sotalol compared with other beta blockers. Sotalol's class III antiarrhythmic action becomes apparent at concentrations higher than those necessary for significant beta-receptor antagonism, both in vitro and in human subjects. In a study correlating dosage and antiarrhythmic response with prolongation of rate-corrected QT (QTc) (a measure of class III action) and the degree of beta-receptor blockade (assessed by the reduction of the maximal exercise-induced heart rate), 11 of 17 patients had an antiarrhythmic response. Eight of these 11 responders had been unresponsive to conventional beta-receptor antagonists. The plasma concentration associated with significant QTc prolongation (2.55 micrograms/ml) was found to be much greater than that associated with 50% reduction in maximal slowing of heart rate (0.8 micrograms/ml). As with other beta-receptor antagonists, the activities of sotalol's 2 stereoisomers differ, with the I-isomer having far more beta-blocking activity. However, both isomers have equal class III antiarrhythmic activity. When increasing doses of the d-isomer of sotalol (50 to 400 mg every 12 hours) were evaluated in patients with chronic ventricular arrhythmias, arrhythmia frequency was suppressed greater than 80% in 3 patients and 50% in 1 patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Missense mutations associated with RFLP haplotypes 1 and 4 of the human phenylalanine hydroxylase gene

We report missense mutations associated with haplotype 1 and haplotype 4 alleles of the human phenylalanine hydroxylase (PAH) gene. Individual exon-containing regions were amplified by polymerase chain reaction from genomic DNA of a PKU patient who was a haplotype 1/4 compound heterozygote. The amplified DNA fragments were subcloned into M13 for sequence analysis. Missense mutations were observed in exons 5 and 7, resulting in the substitution of Arg by Gln at residues 158 and 261 of the enzyme, respectively. Expression analysis in heterozygous mammalian cells after site-directed mutagenesis demonstrated that the Arg158-to-Gln158 mutation is a PKU mutation, whereas the Arg261-to-Gln261 mutation is apparently silent in the assay system. Hybridization analysis using allele-specific oligonucleotide probes demonstrated that the Arg158-to-Gln158 mutation is present in two of six mutant haplotype 4 alleles among the Swiss and constitutes about 40% of all mutant haplotype 4 alleles in the European population. The mutation is not present in normal alleles or in any mutant alleles of other haplotypes. The results provide conclusive evidence that there is linkage disequilibrium between mutation and haplotype in the PAH gene and that multiple mutations have occurred in the PAH gene of a prevalent haplotype among Caucasians.

Expression of a specific protein in spontaneously metastatic fibrosarcoma cell lines and its enhanced synthesis by growth on laminin or fibronectin

A panel of tumor cell lines and clones was generated by selecting for different metastatic capacity in 3AM fibrosarcoma cells. These cell lines were exposed to substrata of various purified extracellular matrix (ECM) proteins and labeled in culture with [35S]methionine. Following analysis by two-dimensional polyacrylamide gel electrophoresis the profiles of total cellular proteins produced by the cell lines displaying different phenotypes were examined. The presence of a specific protein, p54, was related to the cellular metastatic potential, and the synthesis of p54 was influenced by growth on extracellular matrix components. The amount of p54 was minimal and non-inducible in tumor cell lines exhibiting two different phenotypes: (1) experimentally metastatic (EM) and (2) transformed, non-tumorigenic (NTT) cell types. In contrast, all of the five different cell lines capable of both spontaneous and experimental metastasis (SEM), produced p54 either constitutively or through induction by growth on ECM protein substrata of either laminin of fibronectin, but not collagen type IV. These data suggest that the p54 protein may be a unique biochemical marker associated with spontaneous metastatic cell types.

Molecular genetics of PKU in eastern Europe: a nonsense mutation associated with haplotype 4 of the phenylalanine hydroxylase gene

Phenylketonuria (PKU) is a genetic disorder secondary to a deficiency of hepatic phenylalanine hydroxylase (PAH). Several mutations in the PAH gene have recently been reported, and linkage disequilibrium was observed between RFLP haplotypes and specific mutations. A new molecular lesion has been identified in exon 7 of the PAH gene in a Hungarian PKU patient by direct sequencing of PCR-amplified DNA. The C-to-T transition causes the substitution of Arg243 to a termination codon, and the mutant allele is associated with haplotype 4 of the PAH gene. The mutation is present in two of nine mutant haplotype 4 alleles among Eastern Europeans and is not present among Western Europeans and Asians. The rarity of this mutant allele and its restricted geographic distribution suggest that the mutational event occurred recently on a normal haplotype 4 background in Eastern Europe.

[Effect of the resin system on dentin bond strength]

The tensile bond strength for four commercial dentin bonding agents (Gluma Dentin Bond, Dentin Adhesive, Dentin Adhesit and Scotchbond) and two experimental dentin bonding agents, which contains different resin system respectively was tested. The range of bond strength to human dentin for the four commercial products is from 2.6 MPa to 6.2 MPa, the Gluma got the best value among them and for the two experimental dentin bonding agents the value is 16.6 MPa and 12.8 MPa. After thermal cycle (5 degrees C/55 degrees C, 30 sec 1000 periods) the bond strength for all materials fell down obviously, but experimental dentin bonding agent No. 2 kept its value in 9.3 MPa.

Measurement of thermal expansion coefficient of human teeth

The coefficient of thermal expansion of specimens from 60 freshly extracted human teeth were measured over the range 10-80 degrees C using a dilatometer. The coefficient increased rapidly above 50 degrees C, but there was no significant variation with tooth age between 10 and 70 years. The average values obtained were 16.96 (SD 3.83) x 10(-6)/degrees C for enamel, 10.59 (SD 2.38) x 10(-6)/degrees C for dentine, 11.90 (SD 4.42) x 10(-6)/degrees C for crowns and 9.44 (SD 0.61) x 10(-6)/degrees C for roots.

Role of endogenous cholecystokinin on vagally stimulated pancreatic secretion in dogs

Pancreatic exocrine secretion was evoked by electrical stimulation of the vagus nerves (EVS) in dogs to determine whether a gut hormone was responsible for the pancreatic stimulatory activity. In 39 dogs, pancreatic juice was continuously collected to measure volume, bicarbonate, and amylase output, while portal and femoral venous plasma concentrations of gastrin, cholecystokinin (CCK), vasoactive intestinal polypeptide (VIP), and pancreatic polypeptide (PP) were determined by radioimmunoassay. EVS produced a significant increase in the pancreatic secretion. Although concentrations of all four peptides significantly increased in plasma, only CCK at the concentration in venous circulation was bioactive in dispersed rat pancreatic acini preparations. This bioactivity of CCK was completely blocked by CR 1409, a CCK-receptor antagonist. The pancreatic secretion by EVS was reduced significantly by intravenous MK-329 (formerly L364,718) to as low as 22% of control values and was completely suppressed by intravenous atropine. The increment in plasma CCK by EVS was also significantly suppressed by atropine. The present study indicates that increased pancreatic secretion by EVS is in part mediated by endogenous CCK.

Molecular genetics of phenylketonuria in Orientals: linkage disequilibrium between a termination mutation and haplotype 4 of the phenylalanine hydroxylase gene

Phenylketonuria (PKU) is a common metabolic disorder among Chinese, with a prevalence of about 1 in 16,500 births. This frequency is very similar to that among Caucasians. Individual exons of the phenylalanine hydroxylase (PAH) gene with flanking introns were amplified by polymerase chain reaction and cloned into M13 for sequence analysis. An Arg111-to-Ter111 mutation has been identified in exon 3 of the PAH gene in a Chinese PKU patient. The mutation is in linkage disequilibrium with the mutant haplotype 4 alleles which are the most prevalent haplotype among the Orientals. The mutation accounts for about 10% of the Chinese PKU alleles and is absent from the Caucasians, demonstrating that independent mutational events have occurred in the PAH locus after racial divergence.

Polymorphic DNA haplotypes at the phenylalanine hydroxylase (PAH) locus in Asian families with phenylketonuria (PKU)

DNA polymorphisms at the phenylalanine hydroxylase (PAH) locus have proved highly effective in linkage diagnosis of phenylketonuria (PKU) in Caucasian families. More than 10 RFLP sites have been reported within the PAH structural locus in Caucasians. With information from affected and unaffected offspring in PKU families it is often possible to reconstruct complete RFLP haplotypes in parents and to use these haplotypes to follow the segregation of PKU within families and to determine the distribution of PKU chromosomes within populations. To establish the utility of these RFLPs in characterizing Asian families with PKU, we typed eight DNA sites in 21 Chinese families and 12 Japanese families with classical PKU. The eight RFLPs were chosen for their informativeness in Caucasians. From these families we reconstructed a total of 91 complete PAH haplotypes, 44 from non-PKU chromosomes and 47 from PKU-bearing chromosomes. Although all eight marker sites are polymorphic in both Chinese and Japanese, there is much less haplotypic variation in Asians than in Caucasians. In particular, one haplotype alone, haplotype 4, accounts for more than 77% of non-PKU chromosomes and for more than 80% of PKU-bearing chromosomes. Haplotype 4 is also relatively common in Caucasians. The next most common Asian haplotype is 10 times less frequent than haplotype 4. By contrast, in many Caucasian populations the sum of the frequencies of the five most common haplotypes is still less than 80%, and several of the most common haplotypes are equally frequent. Even though the extent of haplotypic variation in Asians is severely limited, the few haplotypes that are found often differ at a number of RFLP sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Neural control of distal tubular bicarbonate and fluid transport

Although previous studies have shown that inhibition of proximal tubular reabsorption of bicarbonate and fluid partially accounts for bicarbonaturia and diuresis observed in the denervated kidney, the role of the distal convoluted tubule in the neural regulation of electrolyte excretion has not been defined. This study was designed to examine the effects of denervation on bicarbonate and fluid reabsorption in the distal convoluted tubules by using in situ microperfusion methods. Early distal tubules were perfused with a solution containing 15 mM bicarbonate at a rate of 12 nl/min, and fluid samples were collected from the late distal tubule. Bicarbonate concentrations were measured as total CO2 by microcalorimetry. The rate of fluid absorption (Jv) was determined using [methoxy-3H]inulin as a volume marker. Before denervation, the rate of bicarbonate absorption (JHCO3-) was 24.7 +/- 2.6 peq.min-1.mm-1, and Jv was 1.80 +/- 0.14 nl.min-1.mm-1. After denervation, marked reductions in JHCO3- (51%) and Jv (60%) were observed. In contrast, sham denervation did not affect JHCO3- or Jv significantly. Our results indicate that the distal convoluted tubule can reabsorb bicarbonate and fluid under physiological conditions. We conclude that the transport processes in this segment of the nephron are regulated by renal nerve activity.

[Uterine spiral arteries of the human in gestosis, fetal growth retardation and postmaturity]

The uterine spiral arteries in humans were examined after a normal course of pregnancy and a pathological course with gestosis, fetal growth retardation and post-term birth. We found that the spiral arterioles in normal pregnancy underwent physiological changes, such as invasion of trophoblasts and decomposition of fibromuscular media and elastic tissue. Apart from the post-term birth, we detected in pathological pregnancies a narrowing of the vascular lumen by proliferation of the intima and often little or no physiological changes of the spiral arterioles in the myometrial segment. Compared to normal pregnancies, thrombogenic formation, swelling of the intima and infiltration of erythrocytes were more frequently observed in post-term births. The flow resistance of maternal blood is greater in cases of gestosis and fetal growth retardation than in normal pregnancies, since the uterine spiral arterioles exhibited a narrowing of the vascular lumen and little or no physiological changes of the vascular wall, and in post-term births also increased thrombogenic formation and swelling of the intima. The resulting decrease in uteroplacental blood flow could lead to a functional insufficiency of the placenta.

Whole-cell clamp study of Xenopus embryonic cholinergic neurons

Whole-cell clamped myoballs are placed into direct visible contact with the growth cones of isolated neurons in embryonic Xenopus culture to serve as probe of acetylcholine (AcCHo) release in order to determine whether these neurons are cholinergic or not. Using a G omega -seal, whole-cell recording method, the electrophysiological properties of these identified cholinergic neurons are studied. It is found that these embryonic neurons, like adult frog motor neurons, exhibit repetitive firings in a certain embryonic developing stage. A development of repetitive firings is observed simultaneously. Tracing the development of one neuron, we find that the development of repetitive firing is completed at the 48th h after fertilization. Tetrodotoxin (TTX) which blocks Na+ channels can abolish all firings; and tetraethyl ammonium chloride (TEA), the blocker of K+ channels, reverses this development, i.e. it makes the repetitive firings disappear again. These data show that the nature of the development of repetitive firings is the development of K+ channels.

Analysis of homomorphic processing for ultrasonic grain signal characterization

A model for the grain signal is presented, which includes the effect of frequency-dependent scattering and attenuation. This model predicts that the expected frequency increases with scattering and decreases with attenuation. Homomorphic processing was used for spectral smoothing, and the selection of parameters for optimal performance was examined. Experimental results are presented that show both the upward shift in the expected frequency with grain boundary scattering and the downward shift with attenuation. Furthermore, it is shown that the expected frequency shift can be correlated with the grain size of the material. It is important to point out that the quantitative relationship between the average grain size and the expected frequency shift (either upward or downward) is dependent on the type of material, the quality of grain boundaries, and the characteristics of the measuring instruments.

Human fetal endometrium--light and electron microscopic study

Human fetal endometrium was examined by light and electron microscopy. Our study shows the following new morphological aspects: (1) Glands are already present. (2) Endometrium undergoes a maturation process during gestation and at late gestational age resembles late proliferative endometrium. (3) The nuclear bodies are present in cell nuclei throughout gestation. (4) Nucleolar channel systems (NCS) sometimes appear at a late gestational age. (5) Cells with the same morphology as that of endocrine cells are found in the basal layers of endometrium at a late gestational age. The significance of these morphological aspects is discussed.