Do neuropeptides in the dorsal horn change if the dorsal root ganglion cell death that normally accompanies peripheral nerve transection is prevented?

Peripheral nerve section causes the death of dorsal root ganglion cells and changes in neuroactive peptides in the dorsal horn of the spinal cord. The relationship between these 2 events has not been previously studied, however. One approach would be to prevent sensory cell death and then determine changes in peptide immunoreactivity. To do this, transected rat sciatic nerve stumps were placed in an impermeable silicone tube for one month. The tube was then removed and after 30 additional days the cells were counted. The data indicate that no cell death occurred. We conclude that the sensory cells are first saved due to some factor present in the tube, and then after 30 days, the cells become independent of the tube and its contents. In these same animals, all of the peptides we examined were significantly changed. Four of the peptides, calcitonin gene-related peptide (CGRP), substance P (SP), cholecystokinin octapeptide (CCK) and galanin (GAL) were significantly depleted in the medial L4-L5 superficial dorsal horn, and vasoactive intestinal polypeptide (VIP) was significantly increased. We conclude that there are major changes in spinal peptide systems following peripheral nerve transection even if there is no accompanying death of sensory neurons. Thus we suggest that dramatic central changes in peptide immunoreactivity following peripheral nerve transection are independent of the sensory cell death that usually occurs in response to this injury.

An anatomical classification of maxillary ameloblastoma as an aid to surgical treatment.

Maxillary ameloblastoma is a different entity from its mandibular counterpart. It is reported to behave more aggressively and have a poorer prognosis. Eleven maxillary ameloblastomas (three recurrent) are reported with a follow-up ranging from 1 month to 12 years with no recurrences. It is proposed that radical treatment of these tumours, with good reconstruction, can give satisfactory function and survival. To that end, the tumours have been classified as to their position in the maxilla and surgical resection related to this.

A cadaver investigation of the blood supply of the galeal frontalis flap.

The vascular anatomy of the galeal frontalis flap was studied in 12 fresh cadavers by an intraarterial dye injection technique. Special attention was directed to the length limit of this flap. The general belief that the galeal frontalis flap has a robust vascularity by means of the supratrochlear and supraorbital arteries was not demonstrated in this study. In the medial half of the forehead, superficial branches of both arteries penetrated the frontalis muscle immediately above the supraorbital rim and ran superficially in the subcutaneous tissue. In the lateral half, some of the superficial branches of the supraorbital artery traveled with the frontalis muscle and anastomosed with the frontal branch of the superficial temporal artery. Deep branches of the supratrochlear and supraorbital arteries showed an axial distribution on the periosteum only for a short distance. One or two branches of the supraorbital artery were found to take a superficial course within the subgaleal layer, pierce the frontalis muscle, and anastomose with the superficial temporal artery. These findings suggest that the galeal frontalis flap should be elevated in the lateral forehead. The preservation of the periosteum with the flap is recommended in order to ensure the temporoparietal extension.

A comparison of upper arm and forearm tourniquet tolerance.

This study examined the use of upper arm and forearm tourniquets for hand surgery. 40 subjects (20 males, 20 females) were randomly assigned to one of four groups: left upper arm, left forearm, right upper arm and right forearm. Tourniquets were applied to these areas. Subjects were asked to rate their discomfort at 10-minute intervals and the total time of tourniquet tolerance was recorded. The results of a three-factor ANOVA revealed no statistically significant differences in either pain rating or tourniquet tolerance between any of the groups. In addition, forearm tourniquets were used in 18 clinical cases. None of the individuals with tourniquet times less than 30 minutes required any medication in order to tolerate this procedure. Of the 13 patients with tourniquet times greater than 30 minutes, ten required medication in order to tolerate the procedure. We conclude that patients tolerate upper arm and forearm tourniquets equally.

Diagnosis of subclinical varicocele in infertility.

The clinically obvious varicocele is perhaps the most common identifiable and correctable cause of male infertility. However, less is known about the subclinical (not palpable) varicocele and its relationship to infertility. We undertook this study to compare the ability of high-resolution sonography and radionuclide scrotal scanning to detect subclinical varicocele. Fifty patients who were referred to our department with a diagnosis of infertility, an abnormal semen analysis, and a normal physical examination of the scrotum underwent both sonography and nuclear scanning. The final study group included 20 men who agreed to surgical ligation of the spermatic vein(s) after a positive sonographic and/or radionuclide study. Sonography was considered positive for subclinical varicocele in 95% of patients, while nuclear scanning was considered positive in only 55%. Postoperatively, all patients showed improvement in their semen and 40% (eight patients) became fertile. Subclinical varicocele seems to be an important causal factor in infertility and, in our experience, high-resolution sonography is superior to radionuclide scanning in its diagnosis.

Absence of neurogenesis of adult rat dorsal root ganglion cells.

Recently, an age-related increase in the number of dorsal root ganglion (DRG) cells was reported in adult rats. This suggests neurogenesis of adult primary afferent neurons, which would be an extremely important phenomenon if it occurred. Other evidence is not compatible with this idea, however, so the issue is not settled. The primary point of contention concerns the counts of DRG cells in relation to age. In our opinion, these disagreements arise, at least in part, because different counting methods give different results for the same material. Thus, any method for determining DRG cell numbers should be calibrated. We previously calibrated some of the common methods used to count DRG cells and found that an empirical method gave accurate cell counts. In the present study, we have used this method and asked whether an age-related increase in the number of lumbar DRG cells can be demonstrated in adult rats. Our data indicate that DRG cell numbers remain essentially constant from 3 to 22 months of age. Most ancillary evidence is consistent with the hypothesis that mammalian DRG cell numbers do not change during adult life. Thus, we feel that the evidence does not support the hypothesis that there is neurogenesis of adult rat primary afferent neurons.

Midface advancement by gradual distraction.

Midface osteotomy was performed on 5 young adult sheep aged 10-12 months. In 4 animals midface advancement by gradual distraction was performed using an external device; one animal served as a control. The midface was advanced by 2 mm per day for 21 days. The amount of advancement was 36 mm in the nasofrontal area and 43 mm on the lateral aspect of the maxilla. After the period of active distraction the midface was maintained with external fixation for an additional 6 weeks to allow for ossification. Radiographs were obtained immediately postoperatively, after 21 days of distraction, and at the end of the 6 week fixation period. New bone formation in the distracted area was obvious radiographically, clinically and histologically. In conclusion, midface advancement by osteotomy and gradual distraction is possible in the sheep model and may offer controlled correction of deformity, obviating the need for the bone grafting.