Chemical dissection of stereovilli from fish inner ear reveals differences from intestinal microvilli

Summary A quick method was developed for isolating the stimulus-receiving apparatus (stereovilli=stereocilia) from the vestibular apparatus of fish (Scardinius erythrophthalmus andRutilus rutilus) in sufficient quantity and purity to study the solubilities and stabilities of their structural elements by electron microscopy. The stereovilli were adsorbed to a support and, after various treatments, negatively stained or metal shadowed after freeze drying. For comparison, and in order to ensure the validity of the method, some experiments were similarly performed on intestinal microvilli from chicken. Microvilli adsorbed to a support gave similar results as in suspension. Stereovilli and microvilli are similar in their architecture, except for the specialized base of stereovilli, and in the Mg²⁺- or Ca²⁺-induced splaying of the actin cores. Major differences occur in the solubilities of the linkers which connect the actin core and the membrane (a-m-linkers). In contrast to microvilli, these linkers are removed from the stereovilli core together with the membrane by Triton-X-100. The linkers together with some membrane components are preserved by glutaraldehyde fixation prior to detergent extraction. In stereovilli, the position of the linkers is recognizable in fixed material. In microvilli the membrane contains so much material, which becomes detergent insoluble after glutaraldehyde fixation, that the linkers become completely obscured.     

Depressive Symptoms Among Reservation-based Pregnant American Indian Adolescents

Objectives To examine rates and correlates of depressive symptoms among pregnant reservation-based American Indian (AI) adolescents from the Southwestern United States (N = 53). Methods Data were derived from a study evaluating a home-visiting program designed to promote positive parenting among young families. Participants included a volunteer, convenience sample of expectant mothers who completed behavioral and mental health self-report questionnaires. Depressive symptoms were assessed using the Center for Epidemiological Studies-Depression scale (CES-D). Three risk domains were analyzed in relation to depressive symptoms: sociodemographics, family relations, and psychosocial functioning. Results Forty-seven percent of expectant mothers scored at or above the widely accepted clinical cutoff score of 16 on the CES-D; 30% scored at or above 20, a score more likely to reflect elevated depressive symptoms among adolescents; and almost 20% scored at or above 28 (one standard deviation above the mean), a score suggestive of clinical depression. Higher levels of depressive symptoms were associated with less use of public assistance, external locus of control, less social support, and lower self-esteem. Conclusions Data suggest that a large proportion of pregnant AI adolescents reported elevated depressive symptoms, though rates are similar to non-pregnant AI adolescent samples.     

Severe osteomyelitis following immediate placement of a dental implant

Risk factors and complications in immediate implant placement are widely discussed. The present report describes a case of severe osteomyelitis as a serious complication after the immediate placement of a dental implant into an extraction socket of a 61-year-old woman. The course leads from initial treatment of recurrent perimandibular abscesses with surgical drainage and high-dose intravenous antibiotics to a refractory osteomyelitis. Hemimandibulectomy and partial mandibular reconstruction with a free fibular flap followed.     

Functional gliding spaces of the dorsal side of the human hand

The clinical and functional importance of gliding spaces of the hand (e.g., their role in the spread of infection or as a consideration in reconstructive surgery) has been repeatedly emphasized. However, only a few studies have provided details regarding the connective tissue spaces in the metacarpal region of the dorsal side of the human hand. The aim of the present study was to analyze the morphology and elucidate the anatomic relation of functional gliding spaces in the metacarpal region on the dorsal side of the human hand in order to provide a better understanding of function, and of clinical disorders and their treatment. To delineate these spaces we used a plastic (Acrifix 90) injection method. Twenty fixed and unfixed cadaver hands were subcutaneously injected with Acrifix 90 (a methacrylate) into the metacarpophalangeal transitional region and into the tendon sheaths of the extensor muscles. Different colors were used to distinguish one injected plastic solution from another. The spreading pattern of the injected medium was analyzed by careful dissection. To delineate the exact bordering structures and the topography of the injected spaces, two hands were plastinated using the E12/E6 technique (von Hagens et al., Anat Embryol 1987;175:411-421), and one hand was injected and embedded in Technovit 7100 for histological investigations. Injecting the plastic into the metacarpophalangeal transitional region of fingers II-IV in a disto-proximal direction, the solution spreads along the surface of the separate extensor tendons. It then coalesces 1-2 cm proximal to the injection points to form a continuous plastic plate, which protrudes between and on top of the previous injected tendon sheaths. In no case was a communication between the paratendinous tissue and the tendon sheaths observed. Laterally, the injected solution is delimited at the radial side of the extensor tendon of the second finger and at the ulnar side of the extensor tendon of the fourth finger. Using the described technique at the fifth finger yields a plastic plate that extends from the injection point to the tendon sheath. However, in two specimens a connection between the plastic injected into the tendon sheath of the fifth finger, and the distal injected solution was observed.     

Sexual potency of patients on chronic hemodialysis

A study was made of sexual function of 22 patients undergoing chronic hemodialysis. Approximately 46 per cent maintained some sexual function. Patients on home dialysis appear to perform better sexually. Patients on chronic hemodialysis may produce a model for the etiology and treatment of organic impotence, a problem which needs further study.     

Analysis ofLegionella pneumophila strains associated with nosocomial pneumonia in a neonatal intensive care unit

A premature child received continuous mechanical ventilation in a neonatal intensive care unit. On day 10 of his life he developed pneumonia due toLegionella pneumophila serogroup 1, monoclonal subtype Bellingham. The strain was cultured from a tracheal secretion taken on day 10 and detected by immunofluorescence using monoclonal antibodies on days 10, 12 and 17.Legionella pneumophila serogroups 1 and 6 (10²–4×10⁴ cfu/l) were cultured from both central and peripheral hot water systems. Monoclonal antibody testing, macrorestriction analysis of the genomic DNA using pulse-field electrophoresis, and electrophoretic alloenzyme typing showed the isolate from the child to be identical to the serogroup 1 strains from the hot water system. Four unrelatedLegionella strains of the same monoclonal subgroup Bellingham were studied for comparison. Legionellae were also isolated from two other incubators, but no clinical or microbiological indications of legionellosis were found in the neonates hospitalised there. Serogroup 1 strains isolated from the patient and from the hot water system and serogroup 6 isolates from the hot water supply were able to multiply in culturedAcanthamoeba castellanii cells and in guinea pigs. The serogroup 6 strain, although prevalent in the incubators, was not found in any of the clinical specimens by either culture or immunofluorescence.     

Changes in the condyle and disc in response to distraction osteogenesis of the minipig mandible.

PURPOSE: Distraction osteogenesis (DO) is a commonly used technique for mandibular lengthening, but changes in the temporomandibular joint have not been well documented. The purpose of this study was to evaluate the effect of DO, at varying rates, on the mandibular condyle and articular disc. MATERIALS AND METHODS: Semiburied distractors were placed via submandibular incisions in 15 minipigs. Two unoperated animals served as controls. The protocol consisted of 0 day latency and rates of 1, 2, or 4 mm/d for a 12-mm gap. After the animals were killed (0, 24, or 90 days), ipsilateral and contralateral condyles and discs were harvested and evaluated to determine changes in 1) condylar form and size, 2) condylar surface, and 3) the articular disc. RESULTS: Articular surfaces of the condyles in control animals were smooth, with no irregularities or erosions. In animals undergoing distraction, ipsilateral condyles showed increasing changes in morphology and AP dimension, and surface contour irregularities as the DO rate increased. These changes were present, but to a lesser degree, in the contralateral condyles. Articular discs of both ipsilateral and contralateral sides showed variable thinning at the medial aspect at end DO. After 90 days, changes in the condyles and discs were reduced by remodeling except in the 4 mm/d DO groups. CONCLUSIONS: Results of this preliminary study indicate that gross changes occur in condyles and discs after unilateral mandibular DO. These changes are more severe at faster distraction rates (4 mm/d) and tend to resolve during neutral fixation when a rate of 1 mm/d is used.     

Association of brain-derived neurotrophic factor (BDNF) haploinsufficiency with lower adaptive behaviour and reduced cognitive functioning in WAGR/11p13 deletion syndrome

In animal studies, brain-derived neurotrophic factor (BDNF) is an important regulator of central nervous system development and synaptic plasticity. WAGR (Wilms tumour, Aniridia, Genitourinary anomalies, and mental Retardation) syndrome is caused by 11p13 deletions of variable size near the BDNF locus and can serve as a model for studying human BDNF haploinsufficiency (+/−). We hypothesized that BDNF+/− would be associated with more severe cognitive impairment in subjects with WAGR syndrome. Twenty-eight subjects with WAGR syndrome (6–28 years), 12 subjects with isolated aniridia due to PAX6 mutations/microdeletions (7–54 years), and 20 healthy controls (4–32 years) received neurocognitive assessments. Deletion boundaries for the subjects in the WAGR group were determined by high-resolution oligonucleotide array comparative genomic hybridization. Within the WAGR group, BDNF+/− subjects (n = 15), compared with BDNF intact (+/+) subjects (n = 13), had lower adaptive behaviour (p = .02), reduced cognitive functioning (p = .04), higher levels of reported historical (p = .02) and current (p = .02) social impairment, and higher percentage meeting cut-off score for autism (p = .047) on Autism Diagnostic Interview-Revised. These differences remained nominally significant after adjusting for visual acuity. Using diagnostic measures and clinical judgement, 3 subjects (2 BDNF+/− and 1 BDNF+/+) in the WAGR group (10.7%) were classified with autism spectrum disorder. A comparison group of visually impaired subjects with isolated aniridia had cognitive functioning comparable to that of healthy controls. In summary, among subjects with WAGR syndrome, BDNF+/− subjects had a mean Vineland Adaptive Behaviour Compose score that was 14-points lower and a mean intelligence quotient (IQ) that was 20-points lower than BDNF+/+ subjects. Our findings support the hypothesis that BDNF plays an important role in human neurocognitive development.