Bone “mass” and the “mechanostat”: A proposal

The observed fit of bone mass to a healthy animal's typical mechanical usage indicates some mechanism or mechanisms monitor that usage and control the three longitudinal growth, bone modeling, and BMU-based remodeling activities that directly determine bone mass. That mechanism could be named a mechanostat. Accumulated evidence suggests it includes the bone itself, plus mechanisms that transform its mechanical usage into appropriate signals, plus other mechanisms that detect those signals and then direct the above three biologic activities. In vivo studies have shown that bone strains in or above the 1500–3000 microstrain range cause bone modelling to increase cortical bone mass, while strains below the 100–300 microstrain range release BMU-based remodeling which then removes existing cortical-endosteal and trabecular bone. That arrangement provides a dual system in which bone modeling would adapt bone mass to gross overloading, while BMU-based remodeling would adapt bone mass to gross underloading, and the above strain ranges would be the approximate “setpoints” of those responses. The anatomical distribution of those mechanical usage effects are well known. If circulating agents or disease changed the effective setpoints of those responses their bone mass effects should copy the anatomical distribution of the mechanical usage effects. That seems to be the case for many agents and diseases, and several examples are discussed, including postmenopausal osteoporosis, fluoride effects, bone loss in orbit, and osteogenesis imperfecta. The mechanostat proposal is a seminal idea which fits diverse evidence but it requires critique and experimental study.     

The facts about “encounter groups: First facts”

The book, Encounter groups: First facts, by Lieberman, Yalom and Miles (1973), probably the most extensive research done on groups, concluded, among other things, that encounter groups are hazardous and ineffective. A reanalysis of the data found that these groups were unrepresentative of encouinter groups because over one-third of the leaders had little or no previous experience in leading encounter groups, and only one-fifth of the leaders were high in emotional stimulation, the major characteristic of encounter group leaders. Also, both “caring” and “emotional stimulation,” or “group intensity,” which is an encounter group characteristic, are beneficial elements in psychotherapy and encounter groups. This reanalysis supported either no difference between encounter and therapy groups, or a slightly greater effectiveness of encounter group methods.     

“Political co‐authorships” in medical science journals

The issue of co‐author relationships on medical sciences journal publications has become more pronounced as advances in technology have enabled collaboration across countries and institutions to occur much more efficiently. These relationships often have underlying political motivations and outcomes, including career advancement, attempting to increase prestige of a project, and maintaining research grants. Some authors may be listed as senior or honorary authors despite offering little or no contribution to the original research project. This may be done in an effort to enhance the gravitas of a research project, and attain publication in a highly regarded medical journal. The current review covers the topic of political co‐authorship and germane literature and lists strategies to combat this phenomenon. Such co‐authorship practices corrupt the integrity of the research process as they attempt to bypass the safeguard that medical journals and institutions have put in place to prevent fraud and falsification. A number of strategies have been proposed to combat the practice of co‐authorship, but it may ultimately be an unavoidable feature of contemporary medical research publishing that is difficult to police. Clin. Anat. 30:831–834, 2017. © 2017Wiley Periodicals, Inc.     

Psychiatric “Co-occurrence”? I'll Stick with “Comorbidlty”

Lilienfeld et al's critique of the use of the term comorbid in psychopathological research is critically examined. They are incorrect in asserting that the original use of the term in medical epidemiology was intended to restrict it to disease entities. Furthermore, the ways in which medical comorbidity can be understood apply equally well to understanding the comorbidity of psychiatric or psychological disorders. Just as it has been useful to use the general term psychiatric disorders to include symptom patterns and syndromes and few If any true diseases, so to it is useful to apply the generic term of comorbidity to the joint occurrence of psychiatric disorders. Because methodological factors can sometimes contribute to artifactual comorbidity which is uninformative about the disorders being studied is no reason to abandon the term comorbidity in psycho-pathological research.     

Social integration and social support: Moving “social support” beyond the individual level

Despite the extra-individual nature of social relationships, social support and social networks have been treated by and large as individual-level concepts. This article describes some of the forms that an individualistic bias takes in our current approaches to conceptualization and measurement of social support and social networks and suggests three steps towards an extra-individual treatment of these concepts: (1) expand notions of social support to encompass social integration; (2) examine the role of groups and settings as social network “members”; and (3) explore functional and structural characteristics of social networks as independent and dependent measures.     

Smith-Lemli-Opitz syndrome: Thirty-year follow-up of “S” of “RSH” syndrome

We have reassessed patient “S,” one of the first 3 individuals recognized to have Smith-Lemli-Opitz (or RSH) syndrome, at age 34 years, and we describe his physical, developmental, and behavioral manifestations. This reassessment provides formal evidence that this individual has the cholesterol biosynthetic defect which is thought to be the cause of Smith-Lemli-Opitz syndrome. Dietary manipulation appears to have had a beneficial effect on the patient's behavior and suggests that even in adults with this condition, dietary cholesterol supplementation may be indicated. Am. J. Med. Genet. 68:260–262, 1997. © 1997 Wiley-Liss, Inc.     

Exploring “personal” and “shared” sense of community identity in Durham City,England

“Personal” and “shared” aspects of sense of community identity are explored in a an established community in Durham City, England. Durham City has a history of over 1,000 years of continuous settlement, and is generally viewed as a stable and relatively harmonious setting. In the study 102 residents responded to a Community Response Questionnaire based on Puddifoot's taxonomy of elements of sense of community. The findings suggest the existence of three underlying “personal” dimensions of Sense of Community Identity (SOCI), namely, “Sense of Personal Support,” “Sense of Personal Contentedness,” and “Personal Involvement,” and three “shared” dimensions of SOCI, namely, “Perceived Community Engagement,” “Perceived Neighborliness,” and “Perceived Settledness.” This article discusses these findings and the prospect of creating a measure for comparative analysis around these dimensions. © 2003 Wiley Periodicals, Inc.     

“WE'VE GOT A GUN?”: comparing reports of adolescents and their parents about household firearms

Firearms are a leading cause of mortality among adolescents, and the guns that adolescents use to harm themselves or others often come from their own homes. In this statewide, multilanguage, community‐based survey of 5,704 coresiding pairs of adolescents and their parents, we asked about guns in the home and compared their responses. The proportions of parents and adolescents responding affirmatively were similar: 25.7% and 26.8%, respectively, for any guns; 15.0% and 13.2%, respectively, for handguns. A paired analysis documented substantial agreement for whether there was any gun in the home and less agreement about whether there was a handgun in the home. The amount of agreement and disagreement was related to household composition and gender of the respondents. The disagreement was substantial for some groups (e.g., when boys residing in households containing a single mother and no other adults reported that there was a gun in the home, 64.8% of their mothers said that there was not a gun in the home). Implications for research and intervention are discussed. © 2007 Wiley Periodicals, Inc.     

“Hypotyrosinemia” in Phenylketonuria

It has been postulated that the significant incidence of learning disabilities in well-treated patients with phenylketonuria (PKU) may be due, in part, to reduced production of neurotransmitters as a result of deficient tyrosine transport across the neuronal cell membrane. Hypotyrosinemia has been reported in treated and untreated PKU but virtually no data are available. We decided to examine this in our patient population and to compare it with the published norms, patient data from our hospital clinical biochemical laboratory database, and a group of normal children and adolescents in a private pediatric practice. We found that the mean nonfasting plasma tyrosine in 99 classical PKU patients was 41.1 μmol/L, in 26 mild (atypical) PKU patients 53.3 μmol/L, and in 35 non-PKU mild hyperphenylalaninemia patients 66.6 μmol/L. This compared to nonfasting plasma tyrosine levels in 102 non-PKU subjects of 64.0 μmol/L in our hospital biochemistry database, 69.1 μmol/L in 58 volunteers in the private office practice, and 64–78.8 μmol/L in infants, children, and adolescents in the literature review. Our data support the previously undocumented statements in the literature that plasma tyrosine levels are low in PKU.     

Endocardial cushion defect: Further studies of “isolated” versus “syndromic” occurrence

The isolated occurrence of endocardial cushion defect (ECD) has been suggested to differ from its occurrence within the context of a syndrome, with regard to the nature (complete or partial) of the defect and the associated cardiovascular malformations. Analysis of data derived from the Baltimore-Washington Infant Study of congenital cardiovascular malformations supports the observation that “syndromic” ECD tends to be of the complete atrioventricular canal type and is less frequently associated with left cardiac anomalies than the isolated form. However, each syndrome has a unique impact on the overall cardiovascular “phenotype,” including the ECD. This is especially true for Down and Ivemark syndromes, which are most frequently associated with ECD, but also for other syndromes as well. It is also suggested that isolated ECD is specifically associated with gastrointestinal and urinary tract anomalies. However, in Down syndrome ECD appears to be a specific cardiovascular expression of the trisomic state that is unrelated to other noncardiac malformations. Additional information on the association of ECD with other less common genetic syndromes is needed in order to further investigate the possible genetic basis of this cardiac defect. © 1992 Wiley-Liss, Inc.     

Mechanical and thermal behaviour of networks with “flexible” and “rigid” chains

“Rigid-rod” telechelics were synthesized via repetitive Diels-Alder reaction of biscyclohexadienes and bis(1,2,4-triazoline-3,5-diones). The bistriazolinediones were used in slight excess. The rigidity of the building blocks and the molecular weight were varied. Various amounts of these reactive telechelics are used to crosslink cis-1,4-polybutadiene. The mechanical and the thermal properties of these two-component networks were investigated by stress-strain, differential scanning calorimetry and dynamic-mechanical measurements. The occurrence of microphase separation between the “rigid” and the “flexible” components is discussed to explain the properties of these materials.