Trunk Function and Ischial Pressure Offloading in Individuals with Spinal Cord Injury

Objective: To determine if there is a relationship between trunk function and offloading of the ischial tuberosities in individuals with Spinal Cord Injury (SCI).

Design: Prospective cross-sectional evaluation.

Setting: Sub-acute rehabilitation hospital.

Participants: Fifteen non-ambulatory participants with complete or incomplete traumatic and non-traumatic SCI, American Spinal Injury Association Impairment Scale (AIS), Classification A-D.

Outcome Measures: Isometric trunk strength using a hand held dynamometer, the ability to reach using the multidirectional reach test and offloading times of the ischial tuberosities using a customized pressure mat.

Results: Participants who were able to engage in the multidirectional reach test were defined as “Reachers”, whereas individuals who were unable to engage in the multidirectional reach test were defined as “Non-Reachers”. Trunk strength was significantly higher in Reachers compared with Non-Reachers (P < 0.05). Offloading times over the left and right ischial tuberosities were lower in Non-Reachers when compared with Reachers, however the results were statistically significant only for offloading over the right ischial tuberosity (P < 0.05). There was no correlation between trunk strength and pressure offloading times for both groups.

Conclusions: Regardless of an individual's ability to engage in a reaching task, participants with spinal cord injury spent more time offloading the left ischial tuberosity compared with the right ischial tuberosity. The study highlights the need to identify factors that may contribute to offloading behavior in individuals with spinal cord injury who lack sufficient trunk strength.     

Synthesis and Evaluation of Long-Acting D-Penicillamine Derivatives

This study extends the use of two lathyrogens, β-aminopropionitrile (BAPN) and D-penicillamine (DPA) from daily systemic or local-topical administration to long-time acting agents. This was achieved by converting the hydrophilic drugs into lipophilic derivatives. The synthesis of functional derivatives of DPA consisted in esterification with methyl-, hexyl-, or benzyl alcohols in the presence of thionylchloride. The esters formed were hydrochlorides, acidic and soluble in water. During neutralization in vitro or in vivo by tissue fluid, an oily substance is formed that elutes from a hydrogel polymer at a much slower rate than hydroplilic DPA itself. The degree of lipophilicity, measured as a partition coefficient between octanol/water, was highest for hexyl ester and lowest for methyl ester DPA. A single injection of either DPA hexyl ester HCl or 3-hexyl(amino) propionitrile into the full thickness skin incision wound in rats significantly lowered the breaking strength of the wound 12 days after injection, indicating the interference with collagen cross-linking. Both agents injected into the breast adenocarcinoma in Fisher rats significantly inhibited tumor growth without any signs of local or systemic toxicity. We conclude that these lipophilic lathyrogens with prolonged effectiveness are suitable in the treatment of pathologies, consisting of excessively cross-linked or deposited collagen (fibrotic adhesions, strictures, stenosis, and scar contractures) and in the treatment of single, solitary tumors, malignant and benign.     

Odontoblasts in odontogenic tumors

Odontoblasts are secretory cells displaying epithelial and mesenchymal features, which exist in a monolayer at the interface between the dentin and pulp of a tooth. During embryogenesis, these cells form a dentin shell and throughout life continue to produce dentin while, also acting as sensor cells helping to mediate tooth sensitivity. In this process, odontoblasts are forced to migrate inwards, resulting in an ongoing loss of pulp volume. Correspondingly, there is also a decrease in the surface area of the dentin which supports the odontoblast cell layer. As these events transpire, odontoblasts maintain a tightly controlled monolayer relationship to each other as well as to their dentin substrate. Stability is maintained laterally by epithelial attachment structures and transversely by complex cytoplasmic extensions into the supporting dentin. As a result, it is not possible for the layer to buckle to relieve the mechanical stresses, which develop during the inward migration. A theoretical consequence of this distinctive self-generated niche is the development of long term compressive stresses within the odontoblast population. We present a mechanobiology model, which causally relates the increase in cellular compressive stresses to contact inhibition of proliferation. We link this hypothesis to the observation that there are no reports of pulpal odontoblasts showing neoplasia or acquisition of changes suggestive of a pre-neoplastic phenotype.     

Moderate Sodium Restriction Enhances the Pressor Response to Hyperlipidemia in Obese, Hypertensive Patients

The effect of dietary sodium restriction on insulin, lipids, and blood pressure has been controversial. Evidence suggests that adverse short-term effects in response to very low-salt diets do not persist long-term with modest sodium restriction. In this study, the effects of modest dietary sodium restriction (60 and 120 mmol sodium) were measured for 3 weeks in 12 lean normotensives and 10 obese hypertensives. Blood pressure, plasma lipids, and the pressor response to an infusion of Intralipid and heparin were obtained. In contrast to previous reports concerning very low-salt diets, obese hypertensives did not manifest a pressor response or an adverse lipid effect with moderate salt restriction. Obese hypertensives were not more salt-sensitive than lean normotensives and did not manifest a different hemodynamic response to 4-hour infusion of Intralipid and heparin while on the 120-mmol/day salt diet. During the 60-mmol/day salt diet, however, plasma triglycerides increased more in obese than in lean volunteers during the Intralipid and heparin infusion (398±38 vs. 264±18 mg/dL; p<0.05), and there were greater increases in mean blood pressure (12±2 vs. 7±2 mm Hg; p<0.05) and systemic vascular resistance (111±38 vs. −25±44 dyne.sec cm—5) as well as a larger decrease in small artery compliance (−2.5±0.6 vs. −0.4±0.6 mL/mm Hg × 100; p<0.05). These data suggest that modest dietary sodium restriction in obese hypertensives does not adversely affect baseline blood pressure or lipids, but it does magnify their adverse lipid and hemodynamic response to fat loading.     

Pulse Wave Velocity for Assessment of Arterial Stiffness Among People With Spinal Cord Injury: A Pilot Study

Background/Objective: The most significant complication and leading cause of death for people with spinal cord injury (SCI) is coronary artery disease (CAD). It has been confirmed that aortic pulse wave velocity (PVW) is an emerging CAD predictor among able-bodied individuals. No prior study has described PWV values among people with SCI. The objective of this study was to compare aortic (the common carotid to femoral artery) PWV, arm (the brachial to radial artery) PVW, and leg (the femoral to posterior tibial artery) PVW in people with SCI (SCI group) to able-bodied controls (non-SCI group).

Methods: Participants included 12 men with SCI and 9 non-SCI controls matched for age, sex, height, and weight. Participants with a history of CAD or current metabolic syndrome were excluded. Aortic, arm, and leg PVW was measured using the echo Doppler method.

Results: Aortic PVW (mean ± SD) in the SCI group (1,274 ± 369 cm/s) was significantly higher (P < 0.05) than in the non-SCI group (948 ± 110 cm/s). There were no significant between-group differences in mean arm PVW (SCI: 1,152 ± 193 cm/s, non-SCI: 1,237 ± 193 cm/s) or mean leg PVW (SCI: 1,096 ± 1 73 cm/s, non-SCI: 994 ±178 cm/s) values.

Conclusions: Aortic PVW was higher among the SCI group compared with the non-SCI group. The higher mean aortic PVW values among the SCI group compared with the non-SCI group indicated a higher risk of CAD among people with SCI in the absence of metabolic syndrome.     

The Value of Predischarge ICD Tests in Patients with a Successful Peroperative Test

An internal cardioverter defibrillator (ICD) is normally extensively tested during implantation. The necessity of retesting prior to discharge of the patient is a matter of debate. In our material of 30 patients undergoing first-time implantation of a transvenous internal defibrillator system, we retrospectively compare the predischarge defibrillation test with the peroperative test. A successful peroperative defibrillation test with no failed shocks at 10 J below maximal energy level was followed by a successful predischarge test with the same safety margin in 18/19 patients, while one patient required a maximal energy ICD shock for conversion at the predischarge test. We conclude that the predischarge defibrillation test can be omitted if the peroperative test was successful, with no failed shocks at 10 J below maximal energy level and if the shock therapy is set to maximal energy level.