Spinal cord dysfunction in Paget's disease of bone. Has medical treatment a vascular basis?

The medical treatment of eight patients with paraparesis associated with Paget's disease of the vertebrae is described. Treatment, for 3 to 87 months, with calcitonin or with diphosphonates produced marked clinical improvement in seven of these patients. From this series and a review of 19 additional case reports it is concluded that favourable clinical response is seen in about 90 per cent of patients, and that this may occur very rapidly. Results are as good or better than those obtained by surgical decompression. It seems possible that paraparesis in some cases may be due to diversion of blood supply from the spinal cord to the highly vascular Pagetic bone giving rise to a vascular "steal" syndrome. It is suggested that medical treatment should be used more widely to avoid or delay the need for operation and reduce the risks of recurrence. These patients, however treated, require lifelong follow-up because relapses are common.     

Quinoxaline derivatives: structure-activity relationships and physiological implications of inhibition of N-methyl-D-aspartate and non-N-methyl-D-aspartate receptor-mediated currents and synaptic potentials.

The inhibitory potencies at excitatory amino acid (EAA) receptors of 11 quinoxaline derivatives were evaluated in two-electrode voltage-clamp recordings of Xenopus oocytes injected with rat cortex mRNA. Currents activated by kainate or (RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) in Xenopus oocytes were inhibited competitively by all the quinoxaline derivatives, with apparent Ki values ranging from 0.27 to 300 microM against kainate and from 0.25 to 137 microM against AMPA. An excellent correlation was observed between inhibitory potencies of the quinoxaline derivatives against kainate and AMPA currents, in support of the contention that in this preparation these two agonists act at a single site. All 11 quinoxaline derivatives also inhibited current activated by the combination of glycine and N-methyl-D-aspartate (NMDA), apparently acting at the glycine site, and did so over a narrower range of apparent Ki values (0.37-8.1 microM). The correlation between the quinoxalines' kainate/AMPA potencies and their glycine/NMDA potencies was relatively weak. Thus, the quinoxaline derivatives were all good antagonists of glycine/NMDA currents and displayed a greater range of potencies against kainate and AMPA. The inhibitory effects of the six quinoxaline derivatives most potent in the Xenopus oocyte experiments were also tested against the excitatory postsynaptic field potential (EPSFP) recorded in the pyramidal cell dendritic field of the CA1 region of hippocampal slices after stimulation of the Schaffer collateral-commissural pathways. In slices superfused with "normal" medium (containing 1 mM Mg2+), in which the EPSFP is mediated primarily by non-NMDA receptors, IC50 values correlated closely with the Ki values against kainate/AMPA obtained in oocyte experiments but were approximately 8-fold higher. Similarly, in slices superfused with nominally Mg(2+)-free medium, in which the EPSFP is amplified due to a relief of the Mg2+ block of NMDA receptors, IC50 values correlated closely with the Ki values against glycine/NMDA obtained in oocyte experiments but were 60-fold higher. This comparison of results from the two experimental systems lends further support to the argument that hippocampal synaptic transmission is mediated postsynaptically by kainate/AMPA-type and NMDA/glycine-type EAA receptors that are pharmacologically indistinguishable from those expressed in mRNA-injected Xenopus oocytes. Furthermore, it suggests that EAA receptors in situ may be nearly saturated by high local concentrations of the endogenous ligands, a condition that would contribute substantially to the apparent non-NMDA receptor selectivity of certain quinoxaline derivatives.     

The use of tapioca as coverage in viral titration]

Virus titration is an important step required on viral vaccines quality control. "Plaque assay", which employs several types of overlay media, is usually used on viral titrations. In this paper we describe the use of Tapioca as an overlay media. Firstly, the toxicity of Tapioca was tested on Vero cells inoculated or not with the Yellow Fever virus (YF) 17DD vaccine strain. Secondly, different batches of the 17DD virus using the Tapioca and Karaya gum as the overlay on Vero cells were tested when higher titres were obtained using Tapioca. Tapioca was also shown to be a suitable overlay to be used in thermostability and plaque reduction neutralization tests. Other systems could benefit from the use of Tapioca as an overlay, since it was possible to titer Measles virus in Vero cells. Tapioca is a cheap Brazilian product, is locally available, easy to use, and reliable. Its use is suggested.     

Chronic immobilization-induced stress increases plasma testosterone and delays testicular maturation in pubertal rats

We investigated whether chronic stress, applied from prepuberty to early puberty, interferes with the spermatogenic and androgenic testicular functions. Male pubertal rats (40 days old) were immobilized 6 h per day for 15 days. Plasma concentrations of corticosterone, prolactin and testosterone were significantly augmented following immobilization, whereas plasma luteinizing hormone decreased and follicle-stimulating hormone was not altered. Acute immobilization (5 min) increased prolactin and testosterone levels in control rats but caused a significantly higher increase in these hormones when superimposed on chronic stress. A lower extent of testicular maturation was observed in pubertal rats immobilized from prepuberty.     

Biomechanics and Classification of the Cartilaginous Structures to Project the Nasal Tip

The present paper is the long-term conclusion of our preliminary presentation at the 1992 ISAPS Congress (Guadalajara, Mexico). This is the result of 29 cadaver dissections of different ages and both sexes. We have observed that length, thickness, and resistance correlate with the possibility to project the nasal tip with the mere structure of the alar cartilage and its medial crurae. We also demonstrated the existence and antagonistic action of Pitanguy's ligament as well as the depressing ligament to project the nasal tip. In this study, besides focusing on classifying the medial crus according to its thickness, length, and resistance, which is already different from any previous classification, we also focused on its surgical utility, and its interaction with other anatomic elements, to achieve the desired projection. Clinically, we present a 12-year experience with 1653 cases operated under this premise.     

Cystic schwannomas of the jugular foramen: clinical and surgical remarks

OBJECTIVE: The goals of this report were to outline the clinical presentation, radiological characteristics, surgical techniques, postoperative morbidity, and long-term follow-up results for cystic jugular foramen (JF) schwannomas and to describe their differences, compared with solid schwannomas involving the JF. METHODS: A retrospective analysis of radiological studies and surgical records identified five primarily cystic tumors among 21 cases of JF schwannomas that had been surgically treated at our institution. RESULTS: Two types of cystic JF schwannomas were observed, i.e., Type 1 lesions, which are single large cysts with thin ring-like enhancement of the tumor wall, and Type 2 lesions, which are multiple cysts with very irregular, thick enhancement of the cyst wall. The most common symptoms were hearing loss, ataxia, and headaches. Total surgical removal could be performed in all cases. The immediate postoperative findings indicated hearing improvement in three cases. No deterioration of lower cranial nerve function was observed. All patients were independent in the immediate postoperative period and in the long-term follow-up period (Karnofsky Performance Scale score, 90). CONCLUSION: Surgical treatment of cystic JF schwannomas can be very demanding because of generally stronger adhesion of the tumor capsule to the surrounding structures, fragile tumor capsules, and difficulty in identification of the arachnoidal planes in some cases. Early identification of the arachnoidal planes without opening of the cyst and sharp dissection may be useful. Careful intradural opening of the JF should be performed to achieve total removal of the last tumor portion within the JF. A comparison of these lesions with solid schwannomas involving the JF indicated that cystic tumors affected a younger population, with less preoperative swallowing impairment (P < 0.05). The immediate postoperative course in both types of cystic JF schwannomas was usually better than for solid lesions, because of minor postoperative cranial nerve morbidity, especially involving lower cranial nerve function, in the latter cases. Long-term follow-up data failed to demonstrate any significant differences in final patient outcomes, however.     

Vascular endothelial growth factor accelerates renal recovery in experimental thrombotic microangiopathy

BACKGROUND: Renal microvascular injury characterizes thrombotic microangiopathy (TMA). The possibility that angiogenic growth factors may accelerate recovery in TMA has not been studied. METHODS: TMA was induced in rats by the selective right renal artery perfusion of antiglomerular endothelial cell IgG (30 mg/kg). Twenty-four hours later, rats received vascular endothelial growth factor (VEGF121, 100 microg/kg/day) or vehicle (control) daily until day 14. To evaluate renal function, the unperfused left kidney was removed at day 14, and rats were sacrificed at day 17. RESULTS: The induction of TMA was associated with loss of glomerular and peritubular capillary endothelial cells and decreased arteriolar density at day 1. Some spontaneous capillary recovery was present by day 17; however, repair was incomplete, and severe tubulointerstitial damage occurred. The lack of complete microvascular recovery was associated with reduced VEGF immunostaining in the outer medulla. VEGF-treated rats had more glomeruli with intact endothelium, less glomerular ischemia (collapsed glomeruli), and greater peritubular capillary density with less peritubular capillary loss. This was associated with less tubulointerstitial fibrosis, less cortical atrophy, and improved renal function. CONCLUSIONS: VEGF accelerates renal recovery in this experimental model of TMA. These studies suggest that angiogenic growth factors may provide a new therapeutic strategy for diseases associated with endothelial cell injury.     

Tc-99m MDP uptake in uterine leiomyoma

A 47-year-old woman with adenocarcinoma of the right breast had bone scintigraphy with Tc-99m MDP. Bone imaging did not show any metastases. However, a large area of increased tracer uptake was seen extending from the abdomen to the pelvis. Abdominal ultrasound revealed a large solid and heterogeneous mass, measuring 18 x 11 x 14.3 cm, that originated in an empty uterus. A biopsy of the surgical specimen showed a leiomyoma of the uterus.