Age-related decline in the osteogenic potential of human bone marrow cells cultured in three-dimensional collagen sponges

Studies with human and animal culture systems indicate that a sub-population of bone marrow stromal cells has the potential to differentiate into osteoblasts. There are conflicting reports on the effects of age on human marrow-derived osteogenic cells. In this study, we used a three dimensional (3D) culture system and quantitative RT-PCR methods to test the hypothesis that the osteogenic potential of human bone marrow stromal cells decreases with age. Marrow was obtained from 39 men aged 37 to 86 years, during the course of total hip arthroplasty. Low-density mononuclear cells were seeded onto 3D collagen sponges and cultured for 3 weeks. Histological sections of sponges were stained for alkaline phosphatase activity and were scored as positive or negative. In the group < or = 50 years, 7 of 11 samples (63%) were positive, whereas only 5 of 19 (26%) of the samples in the group > or = 60 years were positive (p = 0.0504). As revealed by RT-PCR, there was no expression of alkaline phosphatase or collagen type I mRNA before culture, however there were strong signals after 3 weeks, an indication of osteoblast differentiation in vitro. We performed a quantitative, competitive RT-PCR assay with 8 samples (age range 38-80) and showed that the group < or = 50 years had 3-fold more mRNA for alkaline phosphatase than the group > or = 60 years (p = 0.021). There was a significant decrease with age (r = - 0.78, p = 0.028). These molecular and histoenzymatic data indicate that the osteogenic potential of human bone marrow cells decreases with age.

Meniscus cells seeded in type I and type II collagen-GAG matrices in vitro

The objective of this study was to determine the proliferative and biosynthetic activity of calf meniscus cells seeded in type I and type II collagen-glycosaminoglycan (GAG) copolymers with the overall goal to develop a cell-seeded implant for future investigations to improve the regeneration of the knee meniscus. The cell-seeded matrices were digested in protease and analyzed for GAG by a modification of the dimethyl-methylene blue method and assayed for DNA content. Other specimens were evaluated histologically after 1, 7, 14 and 21 days. Contraction of the same types of matrices, seeded with adult canine meniscus cells, was measured at the same time points. After three weeks, cells were observed throughout the type II matrix, whereas the type I matrix was densely populated at the margins. The cell morphology and the cell density after three weeks in both matrices was consistent with the normal meniscus. DNA assay for the type I matrix showed a 40% decrease over the first week and a final amount of DNA that was not significantly different from the initial value, whereas the type II matrix doubled its DNA content over the same time period. The cells continued their biosynthesis of GAG and type I collagen. GAG content of the type II matrix increased by 50% more than the type I matrix after three weeks. Over the same time period, the type I matrix displayed a significant shrinkage to approximately 50% of its initial value whereas in contrast, the type II matrix and the unseeded controls showed no significant shrinkage. The number of cells and the higher GAG synthesis in the type II matrix, and its resistance to cell-mediated contracture, commend it for future investigation of the regeneration of meniscus in vivo.

Medium perfusion enhances osteogenesis by murine osteosarcoma cells in three-dimensional collagen sponges

In this study, we examined in vitro histogenesis by murine K8 osteosarcoma cells maintained in three-dimensional (3D) collagen sponges. We tested the hypothesis that perfusion of medium enhances cell viability and their biosynthetic activity as assessed by expression of the osteoblastic phenotype and mineral deposition. At intervals, samples were harvested and analyzed histologically, biochemically, and by Northern hybridization for type I collagen, osteopontin (OPN), osteocalcin (OC), and core binding factor alpha 1 (Cbfa1). Histologic evaluation showed greater viability, more alkaline phosphatase (ALP)-positive cells, and more mineralized tissue in the perfused sponges after 21 days. Immunohistological assessment of proliferating cell nuclear antigen revealed 5-fold more proliferating cells in the perfused sponges compared with the controls (p = 0.0201). There was 3-fold more ALP activity in the perfused sponges than the controls at 6 days and 14 days (p = 0.0053). The perfused sponges contained twice the DNA and eight times more calcium than the nonperfused controls after 21 days (p < 0.0001 for both). Northern hybridization analysis revealed more mRNA for collagen type I (2-fold) and 50% more for OC at 14 days and 21 days, whereas OPN and Cbfa1 mRNA expression remained unaffected by the medium perfusion. These results show that medium perfusion had beneficial effects on the proliferation and biosynthetic activity of this osteosarcoma cell line. This system mimics the 3D geometry of bone tissue and has the potential for revealing mechanisms of regulation of osteogenesis.

Effect of chronic hypertension on the blood-brain barrier

Disruption of the blood-brain barrier (BBB) during acute hypertension may contribute to hypertensive encephalopathy. In this study we tested the hypothesis that, in chronic hypertension, vascular changes might influence the susceptibility of the BBB to disruption. Spontaneously hypertensive rats (SHR) and normotensive rats (WKY), 3-4 months of age, were anesthetized and acute hypertension was produced by infusing phenylephrine intravenously (i.v.). Permeability of the BBB was studied with radioactive iodine serum albumin (RISA) injected i.v. The ratio of brain-to-blood RISA was used as an index of permeability of the BBB expressed as protein transfer. In both SHR and WKY at resting arterial pressure, the protein transfer was less than 0.10%. In WKY exposed to acute hypertension (mean arterial pressure increased by 87 +/- 7 mm Hg), the protein transfer was 2.77 +/- 0.60%. In SHR with acute hypertension superimposed on chronic hypertension (arterial pressure increased by 80 +/- 7 mm Hg), the protein transfer was 1.16 +/- 0.45% (p less than 0.05, SHR vs WKY). These data suggest that cerebral vessels are less susceptible to disruption of the BBB by acute hypertension in SHR than in WKY. We speculate that the finding of reduced susceptibility to BBB disruption in chronic hypertension may explain, in part, the apparent susceptibility of previously normotensive patients to acute hypertensive encephalopathy.

Regulation of bile acid synthesis in man. Presence of a diurnal rhythm

Regulation of bile acid synthesis in man is incompletely understood, in part because of difficulty in making measurements over short time periods when the enterohepatic circulation is intact. We investigated the possibility of a diurnal rhythm of bile acid synthesis in three human subjects given [26-14C]cholesterol. When this isotope of cholesterol, which is randomly labeled in the 26 and 27 positions, is converted to bile acid, the 14C is released as propionic acid randomly labeled in the 1 and 3 positions. The labeled propionic acid is then oxidized to 14CO2, output of which is a function of bile acid synthesis. However, delays in transit of the 14C through propionic acid and CO2-HCO-3 pools would shift the phase and dampen the amplitude of 14CO2 output relative to an existing diurnal rhythm of bile acid synthesis. Therefore, using constant infusion methods, we determined the turnover constants for conversion to 14CO2 of [1-14C]propionic acid and [3-14C]propionic acid to be 0.36-0.59 h-1 and 0.14-0.16 h-1, respectively. Using these constants and modeling the diurnal rhythm as a cosine function, we determined that amplitude of 14CO2 output from [26-14C]cholesterol was reduced 35% and acrophase was delayed 2.4-3.0 h relative to the diurnal rhythm of bile acid synthesis. None of the diurnal rhythm in 14CO2 output from [26-14C]cholesterol resulted from diurnal variation in propionic acid or CO2-HCO-3 metabolism since constant infusion of [1-14C]propionic acid and [3-14C]propionic acid for 30 h revealed no diurnal variation in output of 14CO2. These studies demonstrate for the first time that humans with an intact enterohepatic circulation have a diurnal rhythm of bile acid synthesis with an amplitude of +/- 35-55% around mean synthesis, and an acrophase at about 9 a.m.

Age-related decline in osteoprotegerin expression by human bone marrow cells cultured in three-dimensional collagen sponges

With advancing age, an increase in bone resorption relative to bone formation results in bone loss. Bone marrow stromal cells and their products support osteoclastogenesis from hematopoietic progenitors. Another of their products, osteoprotegerin (OPG), blocks the osteoclast-stimulatory effects of OPG ligand. We tested the hypothesis that with advancing age there is a decrease in OPG expression by human bone marrow cells. Bone marrow cells were obtained from 18 subjects (age range 38-84 years). Expression of mRNA transcripts of OPG was assessed by quantitative competitive RT-PCR. Median number of OPG transcripts in the younger group was 0. 3 zetptomoles (range 0.01 to 1.30) and was higher than in the older group's median of 0.06 (range 0 to 0.5; p < 0.05). The decline in the expression of OPG with age may increase the capacity of stromal/osteoblast cells to support osteoclastogenesis.

alpha-smooth muscle actin and contractile behavior of bovine meniscus cells seeded in type I and type II collagen-GAG matrices

Many types of injuries to the meniscus of the knee joint result in defects that do not heal, leading to pain and dysfunction. Several ongoing investigations are developing porous absorbable matrices to be used alone or seeded with cultured cells to facilitate regeneration of this tissue. The objective of this study was to evaluate in vitro the contractile behavior of meniscal cells seeded in type I and type II collagen matrices. In many connective tissues, fibroblasts that have assumed a contractile phenotype (myofibroblasts) have been found to play an important role in healing and in pathological conditions. This phenotype, if expressed by meniscal cells, could affect their behavior in cell-seeded matrices developed for tissue engineering. In this study, the presence of a contractile actin isoform, alpha-smooth muscle (alpha-SM) actin, was assessed by immunohistochemistry in normal calf meniscal tissue and in meniscal cells in 2- and 3-dimensional culture. Calf meniscus cells were seeded in type I and type II collagen-glycosaminoglycan (GAG) matrices. The diameter of the matrices was measured every 2-3 days. Immunohistochemical staining of the 2-dimensional cultures for alpha-SM actin was performed after 1, 3, and 7 days and the staining of the seeded matrices was at 1, 7, 14, and 21 days. Transmission electron microscopy (TEM) was performed on selected samples. After 3 weeks the seeded type I matrices displayed a significant shrinkage of almost 50% whereas the type II matrix and both types of unseeded controls showed almost no contraction over the same time period. Positive staining for the alpha-SM actin phenotype was seen in 10% of the cells of the normal tissue but was present in all cells seeded in monolayer and in both types of matrices. TEM of representative cell-seeded matrices showed microfilaments approximately 7 nm thick, consistent with the myofibroblast phenotype. This is the first report of alpha-SM actin containing cells in the knee meniscus. The finding that, under certain conditions, meniscal cells can express the myofibroblast phenotype warrants study of their role in meniscal healing and the tissue response to implants to facilitate tissue regeneration.

Neurologic complications of phenylpropanolamine use

Eleven patients had neurologic symptoms after taking "look-alike" pills thought to contain amphetamines but actually containing phenylpropanolamine. Phenylpropanolamine, a nonregulated drug, is structurally and functionally similar to amphetamines. Acute onset of headache, psychiatric symptoms, or seizures in young patients may be due to phenylpropanolamine use.

Expression of alpha-smooth muscle actin in canine intervertebral disc cells in situ and in collagen-glycosaminoglycan matrices in vitro

The objective of this study was to investigate the presence of a contractile actin isoform, alpha-smooth muscle actin, in annulus fibrosus cells in situ and in two and three-dimensional cultures. Annulus fibrosus cells were isolated from healthy adult dogs, serial passaged, and then injected into porous collagen-glycosaminoglycan copolymers consisting of either type-I or type-II collagen. Alpha-smooth muscle actin was detected in the cells in tissue samples and in culture by immunohistochemistry. The number of cells and glycosaminoglycan content of the matrices were determined after 1, 7, and 14 days, and the diameters of the specimens were measured every 2 days. Although few annulus fibrosus cells in vivo displayed the presence of the alpha-smooth muscle actin isoform, most cells in two-dimensional culture demonstrated this phenotype. The contractile behavior of these cells was shown by the cell-mediated contraction of type-I collagen-glycosaminoglycan scaffolds after 8 days in culture. Glycosaminoglycan production was not significantly different in the seeded type-I matrices than in the unseeded matrices, whereas the seeded type-II matrices had a significant increase in glycosaminoglycan production between days 1 and 14 compared with the unseeded controls. This is the first report of both the expression of the contractile alpha-smooth muscle actin isoform in intervertebral disc cells and the ability of the cells to contract a collagen matrix. This finding could aid in better understanding the nature of cells in the annulus.

Cerebral hemorrhage associated with phenylpropanolamine in combination with caffeine

Phenylpropanolamine (PPA) is a drug that has been associated with serious side effects including stroke. It is often combined with caffeine in diet preparations and "look-alike" pills. In order to determine if PPA/caffeine can lead to stroke in normotensive and/or hypertensive rats, we administered the combination in six times the allowed human dose calculated on a per weight basis for the rats two times per day for five days. Subarachnoid and cerebral hemorrhage was noted in 18% of the hypertensive rats. A single PPA/caffeine administration (same dose) lead to acute hypertension in both the normotensive and hypertensive animals. These results suggest that PPA/caffeine can lead to cerebral hemorrhage in previously hypertensive animals when administered in greater than the allowed dosage. An acute elevation in blood pressure may be a contributing factor.

Achondroplasia and hydrocephalus. A computerized tomographic, roentgenographic, and psychometric study

Nine achondroplastic dwafts were studied with computerized tomography, skull and cervical spine films, and psychometric testing. All had large ventricles that ranged from the top limits of normal to severe hydrocephalus. Three had enlarged cortical sulci. Skull and cervical spine films were typical for achondroplasia, but in addition significant asymmetry of the petrous ridge was noted. Psychometric testing disclosed generally average intelligence quotients which fell below the expected performance level in each case. These findings may be explained on the basis of the abnormal endochondral bone formation found in achondroplasia.

Longitudinal study of the hindquarter vasculature during development in spontaneously hypertensive and Dahl salt-sensitive rats

The purpose of this study was to examine vascular structural alterations longitudinally in spontaneous and Dahl genetic hypertension. Hypertensive and control animals were studied at 5,9-11, and 17-19 weeks of age to permit analysis of prehypertensive, early and established hypertensive stages. Minimal and maximal resistance of the hindquarter vasculature was used as a functional assessment of structural alterations. At 5 weeks of age, the minimal vascular resistance of the spontaneously hypertensive rats (SHR) was elevated over Wistar-Kyoto (WKY) (p less than 0.02) but there was no difference between Dahl salt-sensitive (S) and resistant (R) rats. In both sets of animals, the minimal vascular resistance of the hypertensive group was significantly elevated over controls with age: p less than 0.001 in SHR; p less than 0.001 in Dahl S. The maximal vasoconstrictor response was significantly greater with age in SHR than in WKY, (p less than 0.001), but was not different in Dahl S compared to R. Thus, structural alterations, determined by assessing minimal vascular resistance, are present in both spontaneous and Dahl salt-sensitive hypertension, but the origin of the two differ. An increase in smooth muscle mass, assessed by maximal constriction, contributes importantly to the structural alterations in spontaneous hypertension; in Dahl S, other factors appear to contribute to structural alterations. Further, structural alterations precede frank hypertension in SHR but not in Dahl S hypertension.

Stop touching your face! A systematic review of triggers, characteristics, regulatory functions and neuro-physiology of facial self touch

Spontaneous face touching (sFST) is an ubiquitous behavior that occurs in people of all ages and all sexes, up to 800 times a day. Despite their high frequency, they have rarely been considered as an independent phenomenon. Recently, sFST have sparked scientific interest since they contribute to self-infection with pathogens. This raises questions about trigger mechanisms and functions of sFST and whether they can be prevented. This systematic comprehensive review compiles relevant evidence on these issues. Facial self-touches seem to increase in frequency and duration in socially, emotionally as well as cognitively challenging situations. They have been associated with attention focus, working memory processes and emotion regulating functions as well as the development and maintenance of a sense of self and body. The dominance of face touch over other body parts is discussed in light of the proximity of hand-face cortical representations and the peculiarities of facial innervations. The results show that underlying psychological and neuro-physiological mechanisms of sFST are still poorly understood and that various basic questions remain unanswered.

Global publication productivity in dermatology: a bibliometric description of the past and estimation of the future

BACKGROUND

In the past two centuries, generations of dermatologists around the world have created an enormous number of publications. To our knowledge, no bibliometric analysis of these publications has been performed so far, nor have registered trials been analysed to anticipate future publication trends.

OBJECTIVES

To determine the global distribution of national publication productivity, most published topics, institutions and funding sources contributing most to publications and to anticipate future trends based on registered clinical trials.

METHODS

Following pre-assessment on PubMed, Embase, Web of Science and Scopus, the number of publications for 'dermatology' was determined for each of 195 countries, normalized per 1 Mio inhabitants and bibliometrically analysed. Dermatology-related trials registered at clinicaltrials.gov were specified by the top-10 diagnoses for the top-10 countries.

RESULTS

The search yielded 1 071 518 publications between 1832 and 2019 with the top-5 diagnoses being melanoma, basal cell carcinoma, psoriasis, pruritus/itch and atopic dermatitis. The top-3 countries with highest absolute numbers of publications were the USA (30.6%), Germany (8.1%) and the UK (8.1%), whereas Switzerland, Denmark and Sweden had the highest publication rates when normalized by inhabitants. The most productive affiliation was the Harvard Medical School, the leading funding source the National Institutes of Health. Currently, maximum number of trials are registered in the USA (8111), France (1543) and Canada (1368). The highest percentage of all dermatology-related trials in a specific country were as follows: Melanoma in the Netherlands (24.8%), psoriasis in Germany (21.7%) and atopic dermatitis in Japan (15.9%).

CONCLUSION

The top-10 countries including the USA, Canada, a few European and Asian countries contributed more than 3/4 of all publications. The USA hold the dominant leader position both in past publication productivity and currently registered trials. While most Western countries continue to focus their research on the top-10 topics, China and India appear to prioritize their scope towards other topics.

Quantitative importance of the 25-hydroxylation pathway for bile acid biosynthesis in the rat

During biosynthesis of bile acid, carbons 25-26-27 are removed from the cholesterol side chain. Side-chain oxidation begins either with hydroxylation at the 26-position, in which case the three-carbon fragment is released as propionic acid, or with hydroxylation at the 25-position, in which case the three-carbon fragment is released as acetone. In the present study, we have quantitated the relative importance of these two pathways in vivo by measuring production of [14C] acetone from [14C]-26-cholesterol. Four days after intraperitoneal injection of 20 to 40 muCi [14C]-26-cholesterol and 1 day after beginning a constant intravenous infusion of unlabeled acetone at 25 mumoles per kg per min, 6 male and 2 female Sprague-Dawley rats underwent breath collections. Expired acetone was trapped and purified as the 2,4-dinitrophenylhydrazine derivative. 14CO2 was trapped quantitatively using phenethylamine. Specific activity of breath acetone was multiplied times the acetone infusion rate to calculate production of [14C]acetone. [14C] Acetone production averaged 1.7% of total release of 14C from [14C]-26-cholesterol, estimated by 14CO2 output. The method was validated by showing that [14C] acetone production from [14C]isopropanol averaged 111% of the [14C]isopropanol infusion rate. We conclude that, in the normal rat, the 25-hydroxylation pathway accounts for less than 2% of bile acid synthesis.

Sympathetic nerves exert a chronic influence on the intact vasculature that is age related

The hypothesis of this study is that the chronic presence of intact sympathetic innervation influences the structure, and thereby function, of the rabbit ear vascular bed, and that this influence may be age related. Therefore we examined the effect of chronic sympathetic denervation on vascular resistance of the rabbit ear nine to ten weeks after unilateral superior cervical ganglionectomy. Two age groups were studied: growing juvenile rabbits denervated at 4 weeks of age and adult rabbits denervated at 16 weeks. We assessed the flow-pressure (resistance) curves of the chronically denervated and contralateral innervated isolated rabbit ears during maximum dilation. The flow-pressure curve was significantly shifted downward in the denervated compared to the contralateral innervated ears of juvenile rabbits operated on at 4 weeks (p less than 0.001) but was not different in adult rabbits operated on at 16 weeks. These results support the concept that the sympathetic nerves chronically influence blood vessel properties in growing animals, apart from their acute effect on vasomotor tone.

Reversal of emissary vein blood flow in achondroplastic dwarfs

We used a noninvasive technique--the directional Doppler examination--to determine the direction of flow in an emissary vein of achondroplastic dwarfs. Normally, the direction of flow in this emissary vein is into the orbit. The direction of flow in all 10 achondroplastic dwarfs whom we studied was away from the orbit. This indicates that ophthalmic vein blood flow is reversed in achondroplastic dwarfs, perhaps because there is a pressure gradient between the intracranial and extracranial venous systems.

Enlarged cerebral ventricular system in infant achondroplastic dwarf

The cause of the enlarged head found in achondroplastic dwarfs has been disputed. We studied an infant achondroplastic dwarf who had an enlarged (90%) head at age 2 months without enlarged cerebral ventricles. At age 10 months, her head size further enlarged (95%) and the cerebral ventricles were dilated. Megalencephaly may be the major factor contributing to the enlarged head in newborn achondroplastic dwarfs. Later, enlarged cerebral ventricles also contribute.

Association between sympathetic nerve activity and cerebrovascular protection in young spontaneously hypertensive rats

The purpose of this study was to determine resting and maximal superior cervical sympathetic nerve activity in spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) at five and ten weeks of age as hypertension was developing. Basal cervical sympathetic nerve activity (SNA) of five week SHR was 58 +/- 3 muv* which was significantly elevated over age-matched WKY (SNA = 30 +/- 4 muv, *p less than 0.001) and ten week SHR (SNA = 30 +/- 4 muv, *p less than 0.001) as well as ten week WKY (SNA = 24 +/- 4 muv, *p less than 0.001). Thus, during basal conditions five week SHR nerve traffic was approximately two times that found in age-matched WKY as well as in ten week SHR and WKY. The peak sympathetic nerve activity in response to rapid hemorrhage in five week SHR (215 +/- 16 muv*) was significantly elevated over the maximal response of WKY (140 +/- 23 muv) (*p less than 0.02). Ten week SHR also reached a maximal sympathetic nerve activity (187 +/- 28 muv*) that was significantly elevated over WKY (100 +/- 15 muv) (*p less than 0.02). Thus, both five and ten week SHR had a greater capacity for elevated nerve activity following rapid hemorrhage than age-matched WKY. The elevation in resting cervical sympathetic activity in five week SHR, and the elevated capacity for sympathetic neural response in both five as well as ten week SHR, are consistent with a central nervous system abnormality in SHR that could relate to the previously described protective influence of sympathetic nerves on SHR cerebral blood vessels as hypertension is developing.

Effects, Side Effects and Contraindications of Relaxation Massage during Pregnancy: A Systematic Review of Randomized Controlled Trials

Healthcare professionals and expecting mothers frequently voice concerns that massages during pregnancy might cause complications or premature labor. This PRISMA review outlines current results on effects, side effects and contraindications of relaxation massage during pregnancy. Inclusion criteria: all randomized controlled trials (RCT) comparing relaxation massage during pregnancy with standard care or standard care plus another intervention (i.e., progressive muscle relaxation). Restrictions were full text availability and English language. Results: 12 RCT were included. Trials had good methodological quality but unknown risk of bias. All women were at least 12 weeks gestation at the start of the study. The main benefits of massage during pregnancy were: reduced stress, back and leg pain, depression and anxiety; increased immune response; increased serotonin and dopamine levels; higher fetal birth weight and reduced risk of preterm delivery. Only 2 RCT reported potential side effects of massage, which were minor and transient. Seven RCT excluded women with difficult pregnancies or preexisting complications, five studies did not report preexisting conditions. Those obstetric or postnatal complications that occurred were most likely unrelated to massage treatments. In healthy pregnant women without complications, relaxation massage has positive effects throughout pregnancy. Precautions for massage during pregnancy (i.e., to prevent pulmonary embolism) are discussed.