Steady state hormonal secretion in traumatic quadriplegia.

Physiologically complete cervical spinal cord transection results in motor and sensory quadriplegia and interruption of the sympathetic neural pathways; this condition leads to metabolic deficiencies suggestive of abnormal endocrine function. An investigation of the non-stimulated secretion of some of the hormones influencing metabolism was undertaken by evaluating thyroxine, iodothyronine binding index, testosterone, growth hormone, calcitonin, and parathyroid hormone in venous blood of fasting healthy subjects and quadriplegic patients. The effect of the duration of the paralysis was examined by repeating the evaluations at different periods after onset. The results show that 1) thyroxine was low for 2 months after onset in 21 patients and normal thereafter in 53 patients, 2) testosterone was low throughout the study in 62 patients; the decrease is greatest during the first 2 months, 3) growth hormone was often increased in 46 patients for 8 months after onset, and nearly normal afterward in 25 patients, 4) calcitonin was normal in 22 patients throughout the study, and 5) parathyroid hormone was normal in relation to normal serum calcium as early as 6 days after onset in 79 out of 83 patients. These data do not preclude a parathyroid hormone increase at onset or alterations in the patterns of circadian secretion and in the responses to specific stimulation for the hormones evaluated. Therefore, it may be concluded only that the steady state secretion of these hormones is not altered by traumatic quadriplegia per se, but is temporarily modified by the original insult to the nervous system, and by changes in life pattern and the heavy sedation that follows. The results suggest that the minor endocrin changes occurring in quadriplegic patients during the early period of paralysis will be rapidly overcome by rehabilitation to an active life pattern.

Fractionation of milk fat by short-path distillation.

Fractionation of milk fat by short-path distillation changes the chemical composition and physical properties of the resulting fractions. Increases in distillation temperature from 125 to 250 degrees C increased distillate yield from 0.3 to 42.7% (wt/wt). The distillate was enriched in short- and medium-chain fatty acids and low molecular weight acylglycerols, while the retentate was enriched in long-chain saturated and unsaturated fatty acids as well as high molecular weight acylglyerols. As distillation temperature increased, dropping points of the distillate increased. Relative to native milk fat, the solid fat content (SFC) vs. temperature melting profile of the distillate was depressed and that of the retentate was augmented, which correlated with the saturated long-chain fatty acid content in the fractions. Retentate crystallization parameters obtained by fitting the Avrami model to SFC-time data, did not change as a function of distillation temperature, but varied as a function of the degree of undercooling. Changes in microstructure observed by polarized light microscopy also appeared to be solely a function of the degree of undercooling, with no observable differences between retentates obtained at the different distillation temperatures. In addition, no changes in the retentate's free energy of nucleation (deltaGc) as a function of distillation temperature were found. The compressive storage modulus of the crystallized retentate increased as a function of increasing distillation temperature.

Characteristics of the tonic stretch reflex in spastic spinal cord and head-injured patients.

Spasticity is a known sequelae of spinal cord injury and head injury. We sought to examine whether there were any significant differences in the characteristics or underlying mechanisms of spasticity in these two groups in the chronic period which may be related to the level of injury of the neuraxis. The response to vibration applied to the muscle, or the tonic vibratory reflex, has been shown to be related to the degree of spasticity, and was therefore studied along with phasic reflexes and passive movements. These studies were carried out on cooperative, stabilized patients who were otherwise healthy, 5 with head injuries, and 5 with spinal cord injuries. The patients were examined in a supine position while surface EMG recordings were made of quadriceps and triceps surae muscles bilaterally. Tendon jerk responses, passive and volitional movements, and responses to a powerful vibratory stimulator were measured. In both head injury and spinal cord injury patient groups, a large EMG response was elicited by passive maneuvers, and tendon jerks were exaggerated. The tonic vibratory response, previously shown to be dependent upon brain influence, was present in both groups. These observations suggest that similar suprasegmental mechanisms may be responsible for hypertonia in both head-injured and spinal cord-injured patients.

Remarks on spinal cord stimulation and the placebo effect.

Spinal cord stimulation, which has been shown to be beneficial in multiple sclerosis as well as in sustained spinal cord injury, works through modification of specific motor mechanisms. This modification occurs through regional recruitment of spinal cord activity in posterior aspects of the spinal cord. Substantial involvement of the placebo effect can be ruled out by noting the persistence of beneficial effects observed in spinal cord injury patients and by the fact that the effects are related only to depolarization of posterior structures of the spinal cord, rather than to perception of a 'tingling' sensation caused by spinal cord stimulation. Such a sensation can also occur when electrodes are over anterior or lateral structures of the spinal cord, when the stimulation is not effective in alleviating motor symptoms.

Clinical evaluation of the effect of spinal cord stimulation on motor performance in patients with upper motor neuron lesions.

The effect of chronic electrical stimulation of the spinal cord was evaluated in a group of 24 patients with multiple sclerosis, spinal cord injury, and degenerative disorders of the central nervous system. The systems for stimulation had been implanted from 12 to 30 months prior to completion of evaluation. At the time of completion of evaluation, 23 of the 24 patients still had implanted systems, although 6 of them had not used spinal cord stimulation because of no noticeable effect. In 3 patients stimulation had been disconnected because of technical failure of the system. In 1 patient the system had been removed 8 weeks after implantation because of inflammation in the under-skin receiver pocket. The effects on motor performance of the remaining 14 patients who had continuously active systems were improved bladder control, diminished spasticity, improved movement coordination, and increased endurance.

Bone metabolism in quadriplegia: dissociation between calciuria and hydroxyprolinuria.

Relationships between duration of paralysis, recumbency, muscular activity, and urinary loss of calcium (Cau), phosphorus (Pu), and hydroxyproline (OHPu) were studied daily in 32 traumatic quadriplegic patients during comprehensive rehabilitation and randomly in those readmitted for treatment. Within days after onset, quadriplegic patients had increases in Pu, then OHPu, and finally, Cau. Patients actively engaged in rehabilitation exercises showed a steady fall in OHPu, whereas CAU remained high for up to 18 months. Patients paralyzed for over 18 months (late) had low Cau, Pu and OHPu; but if the patients were kept in bed, OHPu increased rapidly. Patients with early quadriplegia have an increased bone remodeling, suggesting that the excess OHPu and Cau are derived from resorbed bone. Patients with late quadriplegia have little bone remodeling, therefore the excess OHPu occurring during recumbency may be derived from the resorption of new collagen produced during the removal of weight bearing without further change in muscular activity. Resorbed new collagen is excreted in part as large, OHP-containing polypeptides; these were found in the urine of quadriplegic patients, and therefore were present in blood and may play a role in initiating ectopic bone and renal calculi. The presence of OHP in 11 bladder calculi from quadriplegic patients tends to support this hypothesis. These studies indicate that muscular activity and weight bearing influence the bone metabolism of quadriplegic patients and suggest that the presence in body fluids of increased catabolic products from bone may have a role in bone-related complications.