Superior displacement of the hip in total joint replacement: Effects of prosthetic neck length,neck-stem angle,and anteversion angle on the moment-generating capacity of the muscles

The purpose of this study was to determine the effects of superior displacement of the hip center and changes in three prosthetic parameters (neck length, neck-stem angle, and anteversion angle) on the capacity of muscles to generate force and moment about the hip. A three-dimensional model that calculates the maximum isometric forces and moments generated by 25 muscles crossing the hip over a wide range of body positions was used to evaluate the effects of a 2 cm elevation of the hip center and changes in the prosthetic parameters. After superior displacement of the hip center, the neck length was increased from 0 to 3 cm, the neck-stem angle was varied between 110 and 150°, and the anteversion angle was varied between 0 and 40°. Our analysis showed that a 2 cm superior displacement of the hip center would decrease the moment-generating capacity of the four muscle groups studied (abductors, adductors, flexors, and extensors) if neck length were not increased to compensate for decreased muscle length. In the computer model of an adult man that we used, a 2 cm increase in neck length restored the moment-generating capacity of the muscles by increasing muscle length and force-generating capacity. However, a 3 cm increase in neck length increased passive muscle forces substantially, which potentially could limit joint motion. An increased neck-stem angle (i.e., a valgus neck) decreased the abduction moment arm but increased the moment-generating capacity of the other muscle groups. A change in the anteversion angle from 0 to 40° had a relatively small effect on the isometric moment-generating capacity of the muscles studied.     

Comparison of salivary calmodulin binding proteins in Sjögren''s syndrome and healthy individuals

Background: Reduction in salivary secretion is the hallmark of Sjögren's syndrome (SS). Calmodulin (CaM) and calmodulin binding proteins (CaMBPs) play a key role in the secretory process of saliva. Recent studies have suggested that SS‐B, an autoantibody associated with SS, is a CaMBP. This finding suggests that CaMBP may contribute to the loss of saliva in SS. To better understand the role(s) of these proteins in SS, the purpose of this study was to compare salivary CaMBPs in Sjögren's patients and controls. Methods: Saliva samples were collected from 20 patients and 20 age‐, race‐, and gender‐matched controls. CaM overlay was used to identify CaMBPs in saliva of patients and controls. Results: Higher number of salivary CaMBPs was observed among patients than controls. Conclusions: The increased number of salivary CaMBPs in SS may suggest a potential role for these proteins in the pathogenesis of the disease.     

Splenic abscess and peritonitis in a continuous ambulatory peritoneal dialysis (CAPD) patient

A 26-year-old female was on continuous ambulatory peritoneal dialysis (CAPD) because of diabetic end-stage renal failure. She developed an acute peritonitis that relapsed repeatedly despite appropriate antibiotic treatment. Investigations showed the presence of a splenic abscess, and splenectomy and peritoneal cannula removal were required. The patient died of myocardial infarction two weeks postoperatively. This is the first recorded case of peritonitis secondary to splenic abscess in a CAPD patient. Autopsy findings suggest that the abscess developed from infection of a splenic infarct.     

Correlation between the induction of an immediate early gene, zif/268, and long-term potentiation in the dentate gyrus.

Expression of the immediate early gene zif/268 (also termed NGFI-A, Krox 24, TIS8 and Egr-1) was investigated in awake rats following various long-term potentiation (LTP) induction protocols.zif/268 mRNA (Northern blots) and protein (immunohistochemistry) levels sharply increased following LTP, and followed a time course characteristic of other immediate early genes. When measured across 3 tetanization protocols known to produce differing degrees of LTP persistence,zif/268 induction was found to be more highly correlated with LTP duration than with the magnitude of initial LTP. These data support the hypothesis that the immediate early gene zif/268 plays a role as a third messenger in the cascade of cellular and nuclear events that govern the persistence of LTP.     

Decreased platelet vesicular monoamine transporter density in habitual smokers.

The brain vesicular monoamine transporter (VMAT2) is part of the re-uptake mechanism which regulates monoaminergic neurotransmission. We demonstrated previously a high degree of similarity between the pharmacodynamic characteristics of platelet and brain VMAT2. Nicotine induced increase of dopamine and serotonin neurotransmission in limbic structures may alter the expression of VMAT2 in brains of smokers. In this study we measured the VMAT2 pharmacodynamic characteristics using high-affinity [3H]dihydrotetrabenazine (TBZOH) binding to platelets of smokers (n=15) compared to sex and age matched healthy nonsmokers controls (n=14). A significant decrease (17%, P=0.02) in VMAT2 density (Bmax) was observed in platelets of smokers compared to nonsmokers. There was no significant difference in the affinity of [3H]TBZOH to its platelet binding site and the VMAT2 density did not correlate with the heaviness of smoking. The decreased density of the VMAT2 in the platelets of smokers may reflect nicotine induced desensitization of VMAT2, a phenomenon that may be relevant to the addictive properties of nicotine.     

WAIS-R verbal-performance IQ discrepancies in persons with lateralized lesions: utility of a seven subtest short form.

WAIS-R Verbal-Performance IQ difference scores for Ward's (1990) seven subtest short form and the complete WAIS-R were examined in patients with lateralized and diffuse lesions. For both versions, the expected Performance > Verbal pattern was observed in the right hemisphere lesion group, while no summary score differences were seen in the left hemisphere group. Verbal-Performance IQ discrepancies for the short form fell within +/- 5 points of the WAIS-R discrepancy scores in about 75%of the cases, regardless of lesion location. Statistically reliable IQ differences between the complete and abbreviated WAIS-R attained 66%, 91%, and 89% agreement for the left, right, and diffuse groups, respectively. The results support the clinical utility of the seven subtest short form.     

Optic nerve trauma with prolonged blindness followed by visual-evoked potential

An accidental deep intraorbital penetration of a radio antenna tip damaged the optic nerve and caused immediate amaurosis in a 19-year-old female with normal funduscopic, electroretinographic and computerized tomographic orbital findings. A small visual-evoked potential (VEP) recorded within 2 h of injury and in the following days revealed persistent electrical nerve conduction despite loss of vision and afferent pupillary reaction. The VEP constituted the only anticipating sign for the visual recovery which occurred after 3 days. Further increase of the VEP amplitudes preceded the visual improvement, resulting, finally, in 6/24 visual acuity with only lower nasal quadrant scotoma and slight optic disk pallor.     

Non-nociceptive capsaicin-sensitive nerve terminal stimulation allows for an original vasodilatory reflex in the human skin

A significant increase of cutaneous laser Doppler flowmetry was found before blood flow decreases with increasing pressure during a 5 mmHg min⁻¹ increase of pressure strain on the finger. Pre-treatment with a local anaesthetic or chronically applied capsaicin, resulted in the disappearance of the vasodilatory response. These results suggest an original vasodilatory axon reflex response to non-noxious pressure strain which is initiated by capsaicin-sensitive nerve terminals in the human skin.     

Follicular epithelial cell hypertrophy induced by chronic oral administration of 2,3,7,8-tetrachlorodibenzo-p-dioxin in female Harlan Sprague-Dawley rats

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) affects the thyroid morphologically and/or functionally in adult animals. Recently, the National Toxicology Program conducted a 2-year gavage study of TCDD in female Harlan Sprague-Dawley rats. The only treatment-related alterations found in thyroid follicles were decreased luminal size and increased height of the follicular epithelial cells, without prominent protrusion into the lumen. The present study elucidated the nature of these follicular lesions. Thyroid glands of 10 rats each from the control, high (100 ng/kg/day)-dose, and stop-study (100 ng/kg/day, 30 weeks; vehicle to study termination) groups in the 2-year study were evaluated microscopically. Twenty randomly selected follicles were measured morphometrically in each animal. TCDD treatment significantly decreased the mean ratio of luminal/epithelial areas and increased the mean sectional epithelial height of the high-dose group compared to controls. Thyroid sections were immunostained with antibody against minichromosome maintenance (MCM) proteins, a novel cell-cycle biomarker. The MCM labeling index of the high-dose group was significantly higher than that of the control; however, the TUNEL labeling index was also higher in the high-dose group than the control. All data from the stop group were comparable to those from controls. These results indicate that the follicular cell response was hypertrophic and reversible. This information should contribute to diagnosis of nonneoplastic thyroid follicular lesions in rats.     

Incidences of selected lesions in control female Harlan Sprague-Dawley rats from two-year studies performed by the National Toxicology Program

The NTP has a long history of using Fischer rats and has compiled a large database of incidences of lesions seen in control animals. Such a database is lacking for Harlan Sprague-Dawley (SD) rats. The intention of this paper is to report spontaneous lesions observed in female vehicle control Harlan SD rats, and to compare the incidence in 2 strains of rats (Fischer and Harlan SD) used in NTP studies. Female Harlan SD rats served as the test animals for a special series of 2-year studies. Male rats were not used in these studies. Complete histopathology was performed on all animals, and the pathology results underwent comprehensive NTP pathology peer review. The most commonly observed neoplasms in these female control Harlan SD rats were mammary gland fibroadenoma (71%), tumors of the pars distalis of the pituitary (41%) and thyroid gland C-cell tumors (30%). Female Fischer rats had incidences of 44% for mammary gland fibroadenomas, 34% for tumors of the pars distalis, and 16% for thyroid gland C-cell tumors. Fischer rats had a 15% incidence of clitoral gland tumors, while the Harlan SD rats had an incidence of < 1%. In contrast to Fischer F344 rats, the Harlan SD rats had a high incidence of squamous metaplasia of the uterus (44.2%). Squamous metaplasia is not a lesion commonly observed in NTP control Fischer rats. The Harlan SD rats had a very low incidence of mononuclear cell leukemia (0.5%), compared with an incidence of 24% in female Fischer rats.