An American Board of Orthodontics case report

A case report of a Class II, Division 2 malocclusion with a deep anterior overbite, mandibular first premolars lingual to the maxillary first premolars in centric occlusion, and a functional shift on closure, accompanied by moderate facial convexity with a deficient mandible anteriorly and vertically, treated to the standards of the American Board of Orthodontics, is presented.     

Depression of afferent-induced primary afferent depolarization at the lumbar spinal cord following concussive head injury

Afferent-induced primary afferent depolarization (PAD) was depressed for 2-5 min following concussive head injury in the cat, as assessed by dorsal root potentials and augmentation of antidromic dorsal root potentials, both evoked by stimulation of adjacent dorsal roots. These changes in PAD were abolished by spinal cord transection but not affected by midpontine transection. Spontaneous dorsal root potentials, resting amplitudes of antidromic dorsal root potentials and reductions of antidromic dorsal root potentials following tetanic root stimulation were not substantially altered by injury. These findings suggest that concussive head injury depresses spinal interneuronal transmission by neurally mediated processes involving the bulbar brainstem.     

Local demineralization as a model for bone strength reductions in lytic transcortical metastatic lesions.

The structural consequences of bone density changes associated with lytic metastatic lesions were investigated using an experimental model of regular, lytic metastatic lesions in bone. Circular holes were drilled in the mid-diaphyseal cortex of paired adult canine femora. The region around the defect was demineralized in one bone of each pair with 0.8 N HCl. Specimens were tested to failure in four-point bending. Defect size was determined from conventional planar radiographs as the maximum apparent defect diameter divided by the periosteal diameter. Demineralization resulted in irregular defect geometries, which increased the maximum defect dimension 33% to 57% with respect to the original drill hole diameter. Demineralization resulted in additional strength reductions beyond those expected from the original drill hole alone. Despite the irregular demineralization patterns observed, strength reductions were in close agreement with those predicted from data for regular, nondemineralized holes (r2 = 0.93). The results demonstrate that irregular diaphyseal defect borders may not require more complex fracture risk predictors than can be determined from analytic and experimental studies of regular defect geometries. Our results also demonstrate that errors of over 100% can occur when measuring diaphyseal defect size from radiographs that are not optimally aligned with respect to the defect.     

Experimental studies to determine the susceptibility to infection with St. Louis encephalitis virus of five species of Panamanian mosquitoes.

The susceptibility to infection with a Panamanian isolate of St. Louis encephalitis (SLE) virus was evaluated in Culex quinquefasciatus, Haemagogus equinus, Mansonia dyari, Sabethes cyaneus and Deinocerites pseudes. When fed on blood-virus suspensions using the hanging drop or pledget technique, the median infective dose (ID50) of SLE virus for colonized strains of Cx. quinquefasciatus and Hg. equinus was 10(2.8) plaque forming units (PFU)/2 microliters and 10(3.5) PFU/2 microliters, respectively. The susceptibility of F1 and F2 Cx. quinquefasciatus females was similar to the colonized strain by the same technique. When fed on viremic chicks, the ID50 for both Cx. quinquefasciatus and Hg. equinus was 10(0.5) PFU/2 microliters. These results and successful transmission trials indicate that both of these species have the potential to serve as vectors of SLE virus in Panama. Because of their poor feeding response, complete susceptibility profiles were not obtained for the other 3 species tested. They appear to be less susceptible than Cx. quinquefasciatus and Hg. equinus, although Ma. dyari was readily infected after engorging on a blood-virus suspension with a titer of 10(3.0) PFU/2 microliters.     

Treatment of trilateral retinoblastoma with vincristine and cyclophosphamide

Current therapy for patients with trilateral retinoblastoma, consisting primarily of surgical intervention and radiotherapy, has resulted in no long-term survivors. The use of adjuvant chemotherapy has not improved this outcome. After observing a tumor response to cyclophosphamide in a patient with suprasellar retinoblastoma, we treated a subsequent patient with trilateral retinoblastoma with both vincristine and cyclophosphamide. Objective tumor regression resulted. Although the tumor ultimately progressed in both patients, these findings suggest that vincristine and cyclophosphamide are active in patients with intracranial (trilateral) retinoblastoma.     

Rubratoxin B mycotoxicosis in the Syrian hamster: ultrastructural alterations

Rubratoxin B was given to Syrian hamsters as a single intraperitoneal dose of 0.4 mg/kg. Hamsters were killed at 1, 2, 4, and 6 hr after dosing, and the kidneys and liver were fixed by intravascular perfusion. Renal ultrastructural alterations were evident at 1 hr after treatment and were limited to the straight portion of the proximal tubule. The most prominent alterations were brush border disruption, dilation of smooth endoplasmic reticulum, mitochondrial swelling, cytoplasmic rarefaction, myelin figure formation, and swelling of basal interdigitating processes. Renal alterations were suggestive of damage to membrane structure and/or transport functions and interference with cellular bioenergetics. Hepatic alterations were not seen in the rubratoxin B-treated hamsters of this study.     

Peripheral hormone levels in controls and patients with prostatic cancer or benign prostatic hyperplasia: results from the Dutch-Japanese case-control study.

The possible relationship between changes in peripheral hormone levels and the occurrence of prostatic pathology was studied in a case-control study, involving estimation of various plasma hormones in 368 Dutch and 258 Japanese men, who were grouped as controls and patients with benign prostatic hyperplasia, focal prostatic carcinoma, or clinically evident prostatic carcinoma. Results of a number of previous, smaller studies concerning interrelationships between hormone levels in elderly men were confirmed within the Dutch and Japanese groups. Plasma levels of testosterone and estradiol were significantly lower in the Japanese men, when compared with those in Dutch men. Probably as a result of this difference in testosterone levels, the ratio between serum levels of testosterone and sex hormone-binding globulin (SHBG) was decreased in the Japanese men, while the ratio between the concentrations of dihydrotestosterone and testosterone was increased. These differences were also found when results from Japanese subgroups (controls and patients with prostate pathology) were compared with those from the Dutch subgroups. There were no significant differences in plasma androgen levels between Japanese or Dutch prostate cancer cases and their respective control subgroups. These findings do not support a correlation between the lower plasma testosterone levels and a lower incidence of prostate cancer in the Japanese men. Furthermore, no significant differences were found between salivary levels of testosterone or the ratio between testosterone and SHBG in the various Dutch subgroups. In Japanese benign prostatic hyperplasia patients, the testosterone to SHBG ratio was significantly increased. In conclusion, the results of this retrospective, cross-sectional study do not indicate that hormonal levels play a primary role in the origin or promotion of prostatic abnormalities. The finding of a lower plasma testosterone in the Japanese men, however, remains suggestive, warranting a more extensive prospective study.