Glenohumeral stability from concavity-compression: A quantitative analysis

The purpose of this research was to determine the degree to which compression of the humeral head into the glenoid concavity stabilizes it against translating forces. Ten normal fresh-frozen cadaver glenohumeral joints in which the labrum was preserved were used. A compressive load of 50 N was applied to the humeral head in a direction perpendicular to the glenoid surface. Increasing tangential forces were then applied until the head dislocated over the glenoid lip. The tangential force at dislocation was examined for eight different directions, 45° apart around the glenoid. Concavity-compression stability was then examined for an increased compressive load of 100 N. Finally, the protocol with 50 and 100 N of compressive load was repeated after the glenoid labrum was excised. Concavity-compression of the humeral head into the glenoid is a most efficient stabilizing mechanism. With the labrum intact the humeral head resisted tangential forces of up to 60% of the compressive load. The degree of compression stabilization varied around the circumference of the glenoid with the greatest magnitude superiorly and inferiorly. This may be attributed to the greater glenoid depth in these directions. Resection of the glenoid labrum reduced the effectiveness of compression stabilization by approximately 20%. These results indicate that concavity-compression may be an important mechanism for providing stability in the mid-range of glenohumeral motion where the capsule and ligaments are lax. The effectiveness is enhanced by the presence of an intact glenoid labrum.

Convergent synthesis of higher-order oligosaccharides corresponding to the cell-wall polysaccharide of the beta-hemolytic Streptococci group A. A branched hexasaccharide hapten

A convergent synthesis of a hexasaccharide corresponding to the cell-wall polysaccharide of the beta-hemolytic Streptococci Group A is described. The strategy relies on the preparation of a key branched trisaccharide unit alpha-L-Rhap-(1----2)-[beta-D-GlcpNAc-(1----3)]-alpha-L-Rhap which functions both as a glycosyl acceptor and donor. The hexasaccharide is obtained after only three glycosylation reactions. This fully functionalized unit can serve, in turn, as a glycosyl acceptor or donor for the synthesis of higher-order structures. Deprotection gives a hexasaccharide for use as a hapten in immunochemical studies. The characterization of all compounds by high resolution 1H- and 13C-n.m.r. spectroscopy is also described.

The role of the rotator interval capsule in passive motion and stability of the shoulder

The purpose of this study was to characterize the role of the capsule in the interval between the supraspinatus and subscapularis tendons with respect to glenohumeral motion, translation, and stability. We used a six-degrees-of-freedom position-sensor and a six-degrees-of-freedom force and torque-transducer to determine the glenohumoral rotations and translations that resulted from applied loads in eight cadaver shoulders. The range of motion of each specimen was measured with the capsule in the rotator interval in a normal state, after the capsule had been sectioned, and after it had been imbricated. Operative alteration of this capsular interval was found to affect flexion, extension, external rotation, and adduction of the humerus with respect to the scapula. Modification of this portion of the capsule also affected obligate anterior translation of the humeral head on the glenoid during flexion. Limitation of motion and obligate translation were increased by operative imbrication and diminished by sectioning of the rotator interval capsule. Passive stability of the glenohumeral joint was evaluated with the use of anterior, posterior, and inferior stress tests. Instability and occasional frank dislocation of the glenohumeral joint occurred inferiorly and posteriorly after section of the rotator interval capsule. Imbrication of this part of the capsule increased the resistance to inferior and posterior translation.

Laxity of the normal glenohumeral joint: A quantitative in vivo assessment

It is critical that surgeons comprehend the normal laxity of the glenohumeral joint (1) to assist them in diagnosing conditions of clinical instability and (2) to help define a therapeutic end point for the management of shoulders with excessive stiffness. In clinical practice this joint laxity is judged by standard manual tests. We report a quantitative study of the clinical in vivo laxity of the normal shoulders of eight male volunteers. To our knowledge this is the first time that the laxity revealed on standard manual clinical tests has been quantified in vivo. The relative motions of the humerus and scapula were determined with an electromagnetic spatial tracker. This device was pinned percutaneously to the humerus and scapula of each of eight normal male volunteers of ages 25 to 45 years. An experienced shoulder surgeon carried out standard manual clinical tests of glenohumeral laxity while the resulting displacements of the humeral head relative to the glenoid were measured. Spatial tracker data indicated that for each of the different tests, the positions of the glenohumeral and scapulothoracic joints were reproducible for a given subject and among subjects. Substantial glenohumeral translations were measured during those manual laxity tests in which the joint was not at the limit of its range of motion: the drawer test, 7.8 ± 4.0 mm anterior and 7.9 ± 5.6 mm posterior; the sulcus test, 10.6 ± 3.8 mm inferior; and the push-pull test, 9.0 ± 6.3 mm posterior. A minimal translation of 0.3 ± 2.5 mm was measured during the fulcrum test in which the glenohumeral ligaments were under tension. The observed translations were reproducible in each subject's shoulder. On the other hand, there was marked variability among subjects. Even though manual laxity tests are a standard part of the clinical evaluation of the shoulder, our finding that normal glenohumeral joints show substantial translations indicates that translation on clinical manual laxity testing is not in and of itself a sufficient indication for surgical stabilization.

A system for describing positions of the humerus relative to the thorax and its use in the presentation of several functionally important arm positions

The function of the shoulder is to position the arm with respect to the thorax. Humerothoracic positions are commonly described in terms of the degrees of humeral elevation in the sagittal plane (flexion) and/or the degrees of elevation in the coronal plane (abduction). This article proposes a more general system for describing positions of the arm based on the plane of humeral elevation and the angle of elevation within this plane. This system is used to present the humerothoracic positions used by eight normal subjects to perform several activities of daily living as well as those achieved in a range-of-motion examination of the shoulder. Eating, hair combing, and maximal elevation were all performed in a plane approximately 60° anterior to the coronal plane. Between reaching the perineum and washing the contralateral axilla, the humerus functioned in a range of planes extending over 180°.

Evidence for coupling between membrane and cytoplasmic domains of the yeast plasma membrane H(+)-ATPase. An analysis of intragenic revertants of pma1-105

A genetic approach was used to identify interacting portions of the plasma membrane H(+)-ATPase from Saccharomyces cerevisiae. The cellular sensitivity of the pma1-105 strain (S368F) to low external pH and to NH4+ was used to select intragenic revertants of two classes: phenotypically wild-type full revertants and partial revertants that were low pH-resistant but retained resistance to hygromycin B. All 10 full revertants had S368 restored. Among five partial revertants mapping to the original site within the phosphorylation domain, S368L and S368V were each found twice. One revertant contained an E367V substitution adjacent to the original S368F alteration. Four of 13 independently isolated second-site revertants mapped to one site, V289F, in the proposed phosphatase domain. Mutations within the proposed phosphatase and phosphorylation domains resulted in enzymes with increased vanadate sensitivity relative to the vanadate-insensitive S368F enzyme. These results suggest that sites S368, E367, and V289 contribute to a vanadate (Pi) binding domain or are able to interact with such a site within the catalytic domain. The remaining nine partial second-site revertants mapped to six sites within the putative transmembrane regions. Mutations within the transmembrane region had less of an effect on vanadate sensitivity. Most revertant enzymes showed small but significant increases in the rate of ATP hydrolysis relative to the S368F enzyme. Several enzymes no longer displayed the acid-sensitive pH-dependence seen in the S368F enzyme. These data provide novel evidence for an interaction between putative transmembrane helices 1-3 and 7 and the ATP hydrolytic portion of the enzyme.

Hardiness and social support as predictors of psychological discomfort in mothers of children with autism

Mothers of 60 children with autism participated in this study to measure the effects of social support and hardiness on the women's responses to the stressful demands of raising a child with a disability. MANOVA analysis indicated a significant main effect for hardiness, Wilks' lambda = .859, approx. F(2, 55) = 4.494, p less than .02. There were no main effects for social support, or for the interaction of social support and hardiness. In regression analyses, the best combination of predictors of depressive symptoms were the Commitment dimension on the Hardiness Questionnaire and the total score on the Interpersonal Support Evaluation List social support inventory, mult. R = .783, p less than .001. The best predictor of somatic complaints was total Hardiness score, mult. R = .698, p less than .01. There was a significant correlation between hardiness and perceived social support, r(57) = -.67, p less than .001. Results are discussed in terms of the relationship between perceived social support and hardiness and the potential buffering effect of these dimensions.

Changes in cognitive and language functioning of preschool children with autism

Preschool children with autism and their normally developing peers were compared on the Stanford-Binet IV and Preschool Language Scale before and after 1 school year. Both measures showed that although the children with autism functioned at a lower level than their normally developing peers, the children with autism had narrowed this gap after treatment, making a nearly 19-point increase in IQ and an 8-point gain in language quotient. The IQ measure remained stable for the normally developing peers while their language showed a 7.73-point increase. The data support the notion that young children with autism can make very significant developmental gains.

Percutaneous transluminal coronary angioplasty utilizing prolonged balloon inflations: initial results and six-month follow-up

Coronary angioplasty (PTCA) using prolonged balloon inflation has obviated emergency coronary bypass surgery in some patients with acute occlusions at the time of PTCA. However, the use of prolonged balloon inflations has not been shown to improve long-term restenosis rates. As an alternative to the passive autoperfusion catheter, we evaluated a hemoperfusion system in which blood was obtained from the side arm of an arterial sheath and infused through the central lumen of standard balloon catheters via a modified Medrad IV pump during balloon inflation. PTCA was performed in 71 male patients (median age 57 yr). The median balloon inflation time was 4.8 minutes and the median rate of blood perfusion was 30 ml/min. PTCA was successful (lumen increase by 20 percentage points) in 83% of patients (59/71) with diameter stenosis decreasing from a median 82% to 30%. Emergency coronary bypass was required in four patients (5%). Angiographic data for six-month followup was available on 37 patients. The restenosis rate (loss of 50% of gain) was 46% (17/37). The conclusion is that prolonged balloon inflation angioplasty has a role in complicated PTCA but offers no advantage in improving long-term restenosis rates in elective PTCA.

Glycoprotein C of herpes simplex virus type 1 prevents complement-mediated cell lysis and virus neutralization

Glycoprotein gC1 of herpes simplex virus type 1 (HSV-1) binds complement component C3b. To determine if gC1 modifies the interaction of complement with virus-infected cells or cell-free virus, ns-1, a mutant HSV-1 strain that does not express gC1 at the cell surface and does not bind C3b, was compared with its parental strain, NS. Cells infected with the gC1 mutant were more susceptible to cytolysis mediated by antibody and complement or complement alone. The gC1 or gD1 genes were expressed in mammalian cells under the control of an inducible promoter. Cells induced to express gC1 resisted complement cytolysis, while cells expressing gD1 did not. gC1 modified cytolysis of virus-infected or -transfected cells by blocking alternative complement pathway activation. gC1 also modified complement-dependent virus neutralization, which was mediated by inhibiting the classical complement pathway. These results indicate a protective role for gC1 on the virion and at the cell surface.

Traumatic dislocation of the crystalline lens with delayed total retinal detachment

Traumatic dislocation of the crystalline lens usually presents as a visual disturbance that can often be corrected by nonsurgical means. However, this ocular condition is fraught with serious complications that can occur years later. The two most serious complications are glaucoma and retinal detachment. These complications can make treatment of patients with traumatic lens dislocation a dilemma for the optometrist and ophthalmologist alike.

Changes in language development among autistic and peer children in segregated and integrated preschool settings

Five young children with autism enrolled in a segregated class, five other children with autism in an integrated class, and four normally developing peer children in the integrated class were compared for developmental changes in language ability as measured by the Preschool Language Scale before and after training. The results, based on Mann-Whitney U tests, showed that (a) all of the children as a group made better than normative progress in rate of language development, (b) the scores of the autistic children were significantly lower than the peers before and after treatment, and (c) there were no significant differences in changes in language ability between the autistic children in the segregated and integrated classes.

Teaching youths with autism to offer assistance

Three adolescent boys with autism were taught to offer assistance to a person stating inability to complete a task. The study used a multiple baseline across the 3 youths and a multiple baseline across three tasks for each student. Both designs provided clear support for the ability of the youths to discriminate those settings in which offers of assistance were desired. All 3 participants showed relatively rapid acquisition of responding. Generalization was assessed to a new person in the training setting, to a familiar person in a new room at the center, to the mother in the youth's home, and to three novel tasks. Generalization to a new person in the familiar setting was most likely to occur, with very high levels of responding for all 3 youths. Generalization to the other conditions varied across youths, although all 3 boys showed some transfer of skills to all conditions.

Defective H(+)-ATPase of hygromycin B-resistant pma1 mutants fromSaccharomyces cerevisiae

Mutations in the plasma membrane H(+)-ATPase gene (PMA1) of Saccharomyces cerevisiae that confer growth resistance to hygromycin B have been shown recently to cause a marked depolarization of whole cell membrane potential (Perlin, D. S., Brown, C. L., and Haber, J. E. (1988) J. Biol. Chem. 263, 18118-18122). In this report, the biochemical and genetic properties of H+-ATPases from four prominent hygromycin B-resistant pma1 mutants, pma1-105, pma1-114, pma1-147, and pma1-155, are described. Single base pair changes were identified in pma1-105, pma1-114, and pma1-147 that resulted in amino acid substitutions of Ser-368----Phe, Gly-158----Asp, Pro-640----Leu, respectively. An A----G transition mutation at -39 in the 5'-untranslated region of the mRNA of pma1-155 was also found. This mutation creates an out-of-Frame upstream AUG initiation codon that apparently reduces normal translation of PMA1. DNA sequence analysis of PMA1 from strain Y55 identified 9 base pair substitutions that resulted in 6 amino acid changes in nonconserved regions when compared to the published sequence for strain S288C. Plasma membranes of three of the four pma1 mutants contained normal amounts of H(+)-ATPase; membranes from pma1-155 contained enzyme at 62% of the wild-type level. The kinetics of ATP hydrolysis were most strongly altered for enzymes from pma1-105 and pma1-147 which showed changes in both Km and Vmax. A striking pH dependence for these parameters was found for enzyme from pma1-105 which resulted in a precipitous decline in Km and Vmax below pH 6.5. ATP hydrolysis by enzymes from pma1-105 and pma1-147 was insensitive to inhibition by vanadate. These enzymes, in contrast to wild-type and vanadate-sensitive mutant enzymes, were poorly protected from trypsin-induced inactivation by MgATP and vanadate or Pi alone. These results are pertinent to the mechanism of vanadate-induced enzyme inhibition and suggest that Ser-368 and Pro-640 influence the affinity of the phosphate-binding site for Pi. All mutant enzymes catalyzed ATP-induced pH gradient formation following purification and reconstitution into liposomes. Finally, these results further demonstrate the usefulness of hygromycin B as a generalized screening tool for isolating diverse plasma membrane ATPase mutants.

Clinical experience with HIV-infected patients at the University of Oklahoma Health Sciences Center

Two hundred seventy-two patients infected with human immunodeficiency virus (HIV) have received care from the members of the adult infectious disease section at the University of Oklahoma Health Sciences Center. The majority of these patients met the diagnostic criteria for acquired immunodeficiency syndrome. This group of patients was characterized by relatively few parenteral drug abusers, a high incidence of disseminated histoplasmosis, and an unexpectedly low frequency of toxoplasmosis. The prevalence of risk behaviors and endemic disease may be responsible for these particular case distributions.

Plantar motoneuron columns in the rat

In the rat, the numbers and locations of motoneurons innervating the short plantar muscles of the hindlimb (supplied by the medial and lateral plantar nerves, as well as a branch of the sural nerve) were determined by using both horseradish peroxidase (HRP) and fluorochromes as retrograde labels. Topographical organization within the plantar motor nucleus was examined by exposing individually the cut ends (encapsulated in low melting-point paraffin) of medial plantar, lateral plantar, and sural nerves to HRP. In addition, double-labeling experiments were conducted in which the medial plantar nerve was labeled with one fluorochrome (either true blue or diamidino yellow) and the lateral plantar nerve with another. The plantar motor pool is located in the extreme dorsolateral portion of the ventral horn, usually concentrated in the fifth lumbar (L5) spinal segment. Labeled motoneurons extended caudally into the sixth lumbar (L6) segment and rostrally into portions of the fourth lumber (L4) segment. Motoneurons of the medial plantar, lateral plantar, and sural nerve have overlapping territories. Sural motoneurons (about 70 cells per side) are generally confined to L5, medial plantar motoneurons (about 180 cells per side) tend to be concentrated in caudal L5 and rostral L6, whereas the lateral plantar motoneurons (about 310 cells per side) extend throughout the entire length of the plantar motor pool. The distribution of motoneuronal cell size is unimodal (mean cross-sectional area = 610 +/- 150 microns2). Cell bodies of plantar motoneurons tend to have similar geometries in all three major planes of sectioning. In all, the combined plantar plus sural nerve population amounts to about 560 motoneurons on each side of the spinal cord. On the basis of these data, and those published by others, the innervation of the small muscles of the foot accounts for about 25% of the motor axons carried by the entire sciatic nerve.

Binding of complement component C3b to glycoprotein gC of herpes simplex virus type 1: mapping of gC-binding sites and demonstration of conserved C3b binding in low-passage clinical isolates

The sites on glycoprotein gC of herpes simplex virus type 1 (HSV-1) which bind complement component C3b were evaluated by using anti-gC monoclonal antibodies and mutants which have alterations at defined regions of the glycoprotein. Monoclonal antibodies were incubated with HSV-1-infected cells in a competitive assay to block C3b binding. Each of 12 different monoclonals, which recognize the four major antigenic sites of gC, completely inhibited C3b binding. With this approach, no one antigenic group on gC could be assigned as the C3b-binding region. Next, 21 gC mutants were evaluated for C3b binding, including 1 which failed to synthesize gC, 4 which synthesized truncated forms of the glycoprotein such that gC did not insert into the cell's membrane, and 16 which expressed gC on the cell's surface but which had mutations in various antigenic groups. Eleven strains did not bind C3b. This included the 1 strain which did not synthesize gC, the 4 strains which secreted gC without inserting the glycoprotein into the cell membrane, and 6 of 16 strains which expressed gC on the cell surface. In these six strains, the mutations were at three different antigenic sites. One hypothesis to explain these findings is that C3b binding is modified by changes in the conformation of gC which develop either after antibodies bind to gC or as a result of mutations in the gC gene. Attachment of C3b to gC was also evaluated in 31 low-passage clinical isolates of HSV-1. Binding was detected with each HSV-1 isolate, but not with nine HSV-2 isolates. Therefore, although mutants that lack C3b binding are readily selected in vitro, the C3b-binding function of gC is maintained in vivo. These results indicate that the sites on gC that bind C3b are different from those that bind monoclonal antibodies, that antibodies directed against all sites on gC block C3b binding, and that C3b binding is a conserved function of gC in vivo.

Parents and grandparents view the autistic child

Mothers, fathers, grandmothers, and grandfathers of 19 autistic children completed a questionnaire describing their view of the handicapped child, the impact of the child on the parent, and the relationship between the parents and grandparents. Paired t tests revealed that whenever there was a significant difference between the generations, grandparents took a more positive view. For example, maternal grandmothers had a more positive view of the child than did their daughters, and paternal grandmothers had a more positive view of their relationship with their son than did the son. Grandmothers demonstrated an empathic understanding of their daughter's experiences. There was a significant Pearson product-moment correlation between grandmothers and grandfathers in overall scores, their view of the child, and how they viewed their son's or daughter's experiences as the parent of a handicapped child. Maternal grandparents visited the family significantly more often than paternal grandparents. The study offers us a first empirical look at grandparents and their autistic grandchild.

Teaching of labels: an analysis of concrete and pictorial representations

The relationship between the use of concrete objects and pictorial representations of those objects when teaching noun labels to 3 autistic boys was analyzed. A multiple baseline design, counterbalanced for the type of stimulus presentation, was used to teach four sets of five objects and their pictorial representations to the youngsters. Although results indicated no consistent functional relationship between the two types of stimulus presentation, there were varying degrees of generalization between the two conditions. Findings suggest that there is a need to facilitate greater and more consistent generalization from pictures to the realities they represent.

Language environments of autistic and normal children matched for language age: a preliminary investigation

The language patterns of the mothers and fathers of four autistic boys were compared with those of the parents of four normal boys matched for language age with the autistic children. Language patterns were assessed during two 20-minute free-play sessions videotaped in the subjects' homes. The tapes were reliably coded using an 11-category coding system. Only one difference between the language patterns of the parents of the autistic and normal children emerged: The parents of the normal children engaged in a greater proportion of adult-directed language than did the parents of the autistic children. Comparison of the language patterns of mothers and fathers revealed similarities and differences. Both the frequency and percentage of occurrence scores for direct requests for language were significantly greater for mothers than for fathers. However, although the frequency of reinforcement for language did not differ across the sexes, fathers had a greater percentage occurrence score than mothers. There were no other significant differences between the mothers and the fathers.

The acquisition of language skills by autistic children: can parents do the job?

The mothers and fathers of 11 preschool autistic children were taught operant procedures used in teaching speech to nonverbal children. The children's speech skills were assessed twice before and once after their parents were trained. At posttreatment, the children showed significant gains in prespeech and speech skills as measured by a 21-step hierarchy of speech behaviors. Those children who had acquired at least verbal imitative skill after training made greater progress than those who had not. Although children maintained their gains in a 1-year follow-up assessment, there was no evidence of significant improvement beyond that achieved at the end of training. The importance of support for parents in continuing to do formal "teaching" after the training program ends was stressed.

The limits and motivating potential of sensory stimuli as reinforcers for autistic children

This study investigated the reinforcing properties, limits, and motivating potentials of sensory stimuli with autistic children. In the first phase of the study, four intellectually retarded autistic children were exposed to three different types of sensory stimulation (vibration, music, and strobe light) as well as edible and social reinforcers for ten-second intervals contingent upon six simple bar pressing responses. In the second phase, the same events were used as reinforcers for correct responses in learning object labels. The results indicated that: (a) sensory stimuli can be used effectively as reinforcers to maintain high, durable rates of responding in a simple pressing task; (b) ranked preferences for sensory stimuli revealed a unique configuration of responding for each child; and (c) sensory stimuli have motivating potentials comparable to those of the traditional food and social reinforcers even when training receptive language tasks.

Generalization from school to home with autistic children

This investigation assessed the generalization of verbal behavior from school to home with three autistic boys. The study attempted to expand upon previous research by Handleman (1979) by analyzing the effects of single versus multiple trainers on generalization. By the use of a multiple-baseline design counterbalanced for treatment condition, the three youngsters were taught responses to common questions in two school settings and were probed to determine transfer of learning to their homes. All three children demonstrated greater generalization when they received training at varied locations as opposed to instruction in a single setting. Results of the study suggest that manipulating the school environment to more closely simulate home conditions may facilitate transfer of treatment gains to the natural setting.

Suppression of self-stimulation: three alternative strategies

Four boys with autistic-like behavior were treated for self-stimulatory behavior with three different treatment procedures--time out, differential reinforcement of other behavior (DRO), and overcorrection. All four boys showed a rapid response to the overcorrection procedure. Three boys demonstrated some evidence of decrement in responding with time-out. During the DRO procedure, one showed a modest decrease, two showed no change, but one exhibited a consistent increase in responding under this condition. A multiple baseline applied to one of the subjects failed to reveal any generalization of suppression from one setting to another. A strong but not perfect relationship was found between a frequency and a duration measure of self-stimulation. There was some evidence of negative side effects for one boy during overcorrection and for another during time-out. None of these negative side effects was enduring. There was also some indirect evidence that overcorrection facilitated appropriate play.

Behavior modification in the home: siblings as behavior modifiers, parents as observers

It was hypothesized that siblings could function as effective behavior change agent for their behaviorally disturbed brother and sisters within the home environment. Further, it was predicted that parents could be trained to be reliable observers of their children's performance under these circumstances. The results of the study supported both predictions with siblings in two separate families demonstrating their ability to work with their brother or sister within the context of an ABAB reversal design. Parents were also shown to obtain consistently high reliability ratings when compared to outside observers. The judicious use of siblings as behavior modification aides is recommended as a treatment procedure.

Increasing isolate and social play in severely disturbed children: intervention and postintervention effectiveness

A group treatment procedure was instituted in Study 1 to increase the isolate and social play of 4 severely disturbed children. The results indicated that play behavior could be increased significantly by the use of food and social reinforcement and by the use of passive shaping, but that it quickly declined when the intervention was terminated. Social play, however, did remain above baseline levels during extinction. Study 2 replicated the results of Study 1 with a second group of older children, also severely disturbed. However, the procedure of fading adult intervention proved an effective method for increasing the resistance of social play to extinction relative to Study 1. A PROCEDURE OF CONtinuous and multiple-observer reliability assessment was employed for both studies, and the positive results and the methodological implications of the procedure are discussed.