“My crooked vision”: The well sib views ataxia-telangiectasia

The ataxia-telangiectasia gene (designated ATM) has been identified by positional cloning. Retrospective studies in cystic fibrosis (CF) have shown that the illness and death of a sib have far-reaching ramifications on the surviving sib's life. However, there have been no studies on sibs of children and adults with ataxia-telangiectasia (A-T). Thirty-five sibs from 24 families, including 26 adults and 9 adolescents, were drawn from the University of California, Los Angeles; the A-T Clinical Center at the Johns Hopkins University School of Medicine; and the A-T Children's Project Interviews indicated that, unlike CF, the visibility of A-T caused less resentment of time or attention given to the affected, less guilt, and less identification or idealization of the affected, but more embarrassment and shame. It may be said that, unlike CF, the dynamic is one of burden rather than trauma. The specific phenotypic expression of a genetic illness predisposes the way in which the well sib will encounter problems. In A-T affected families, one must help families locate caregiving resources so they will not burden their well children; sibs need help with managing feelings of embarrassment and shame. Geneticists must be alert to understanding characteristic differences of disorders they encounter in order to offer the most appropriate support to affected families. Am. J. Med. Genet. 87:420–425, 1999. © 1999 Wiley-Liss, Inc.     

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.     

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.     

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.     

The “long-thumb” brachydactyly syndrome

A unique variety of brachydactyly associated with skeletal and joint anomalies and possible cardiac conduction defects has been observed in three generations of one family in a pattern consistent with autosomal-dominant transmission. This combination of anomalies has not previously been seen together as a single syndrome. We report clinical and radiographic studies in three of the four affected family members.     

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.     

The “Ins” and “Outs” of the Depressive Disorders Section of DSM‐5

In this article, we review and evaluate changes in the depressive disorders section from DSM‐IV to DSM‐5. We describe characteristics of three new depressive disorders: disruptive mood dysregulation disorder, premenstrual dysphoric disorder, and persistent depressive disorder. We also discuss the controversial decision in DSM‐5 to remove the bereavement exclusion from the criteria for major depressive disorder. Next, we review the decision to replace the diagnosis of depressive disorder not otherwise specified with two new diagnoses: other specified depressive disorder and unspecified depressive disorder. Finally, we discuss the inclusion of two novel specifiers in the DSM‐5 depressive disorders section: “with anxious distress” and “with mixed features.” For each of these changes, we examine the relevant research and discuss implications of the changes for research and clinical practice.     

The Effects of “Immunosympathectomy” on Blood Pressure and Vascular “Reactivity” in Normal and Spontaneously Hypertensive Rats

Newborn litters of spontaneously hypertensive rats (SHR) and normotensive control rats (NCR) were identically treated with sympathetic nerve growth factor antiserum (Wellcome) which markedly interferes with adrenergic cardiovascular control (Zaimis 1967). Blood pressure, measured intermittently during 8 months, was in treated SHR (SHR_is) about 25 % higher than in NCR_is, their respective pressures being about 40 % and 25 % lower than those of sham-treated SHR and NCR.–The hindquarters of one SHR_is, or NCR_is, were then perfused at constant flow in parallel with those of ordinary NCR. Starting from maximal vasodilatation, resistance increases were induced by graded noradrenaline (NA) infusions, from “threshold” to maximal pressor responses. Compared to NCR_is, SHR_is showed an increased resistance at maximal dilatation, an increased slope of the NA dose-response curve and an increased maximal pressor response, while their NA “thresholds” did not differ significantly. Thus, the structurally determined hemodynamic differences between ordinary SHR and NCR (Folkow et al. 1970 b) characterize also SHR_is and NCR_is, though to a reduced extent. Even when comparing SHR_is with ordinary- NCR, which exhibited similar “resting” pressures, these differences partly remain, suggesting that the SHR resistance vessels might, for genetic reasons, be more prone to adapt structurally to pressure loads than those of NCR.     

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.     

Regulation of Respiration: “The Black Box”

A close relation between the state of wakefulness, the electroencephalogram, and the respiration has been demonstrated (Bülow 1963). In the present paper it was assumed that as opening and closing of the eyes influence the EEG and thus probably the state of wakefulness, the responsiveness of the respiratory center may likewise be influenced by the single act of closing the eyes. Seven subjects were studied in the steady state of rest breathing ambient air, 4–5 % CO₂ in air, or 11 % O₂ in nitrogen. In experimental periods of 4–5 minutes their pulmonary ventilation and alveolar Pco₂ were measured while they randomly were either reading a book, or were blindfolded. It was found that in all three conditions closing of the eyes resulted in a mean decrease of V_E of 8 to 14 % with a concomitant increase of PACO₂ of about 1 mmHg. It is tentatively suggested that other and stronger central or peripheral stimuli impinging on the reticular formation of the brain may explain the changed sensitivity of the respiratory center towards the chemical stimuli in conditions like exercise, chronic hypoxia etc.