Thoracoscopic Assisted Pneumonectomy

A lung carcinoma with tumor involving more than one lobe or in close proximity to the mainstem bronchus often requires pneumonectomy for surgical cure. Inflammation, bulky tumors, and dense adhesions limit the operative field of vision and may result in the abandonment of procedures with potential for complete extirpation. This case illustrates the utility of thoracoscopy in visualization of the hilum and other neurovascular structures in a patient with a proximal tumor and dense intrathoracic adhesions. Successful resection was made possible by use of combined open and thoracoscopic modalities.     

Sevelamer hydrochloride with or without alphacalcidol or higher dialysate calcium vs calcium carbonate in dialysis patients: an open-label, randomized study.

BACKGROUND: Sevelamer hydrochloride was recently proposed as a phosphate binder to prevent hypercalcaemia in place of calcium alkaline salts in dialysis patients. So far, it has been evaluated only in patients receiving calcitriol, without comparison with CaCO(3) alone, although the latter was found to be as effective as the combination of calcitriol and Al(OH)(3) in suppressing parathyroid hormone (PTH) without inducing hypercalcaemia and to have a better lowering effect on serum phosphate. Moreover, this bile salt binder may decrease serum 25-OH vitamin D. Therefore, we compared for 5 months two strategies for controlling moderate hyperparathyroidism: CaCO(3) alone vs sevelamer in conjunction with measures to increase calcium balance. METHODS: Forty-two patients were randomized: 21 continued their treatment with 4.8 g/day CaCO(3) and 21 were switched to sevelamer (initial dose: 2.4 g/day, increased to 4.4 g/day). Each month, when serum-corrected calcium decreased below 2.30 mmol/l, dialysate calcium was increased or alphacalcidol was given at each dialysis session, according to serum PO(4) levels. The following parameters were monitored: serum Ca, PO(4), bicarbonate and protein, weekly; and serum PTH, 25-OH vitamin D and total, LDL and HDL cholesterol monthly. RESULTS: Except for higher serum phosphate at month 1, lower serum bicarbonate at month 2 and lower LDL cholesterol at month 5 in the sevelamer group, no difference was found between the two groups. Compared with baseline levels, PTH increased and 25-OH vitamin D decreased significantly in both groups, these two parameters being inversely correlated. CONCLUSIONS: Given comparable control of plasma calcium, phosphate and 25-OH vitamin D, PTH control is comparable in both strategies. Sevelamer does not induce greater vitamin D depletion than CaCO(3). The transient decrease of serum bicarbonate after discontinuation of CaCO(3) in the sevelamer group suggests a less optimal prevention of acidosis. The sevelamer-induced decrease in LDL cholesterol gives this drug a potential advantage in cardiovascular prevention.     

Pheochromocytoma and paraganglioma: comparison of MR imaging with CT and I-131 MIBG scintigraphy

To ascertain the magnetic resonance (MR) imaging characteristics of pheochromocytomas and paragangliomas and to compare MR with computed tomography (CT) and iodine-131 metaiodobenzylguanidine (I-131 MIBG), 19 patients (18 with pheochromocytomas, one with a paraganglioma) were studied. The 18 patients with pheochromocytomas had had positive findings with I-131 MIBG scintigraphy. Abdominal pheochromocytomas were generally hypointense compared with normal liver on T1-weighted MR images and extremely hyperintense on T2-weighted MR images. MR imaging was preferable to CT in the evaluation of primary pheochromocytomas due to superior tissue characterization, particularly in the patient with hypertension and borderline catecholamine levels. For patients with recurrent or metastatic disease, the data suggest that I-131 MIBG scintigraphy is the examination of choice.     

A reassessment of the risk of multiple sclerosis developing in patients with optic neuritis after extended follow-up.

One hundred and one of 146 patients presenting with isolated idiopathic optic neuritis, previously reviewed in 1978, were reassessed clinically, and retyped for HLA antigens and Factor B alleles, after a mean follow-up of 11.6 years. Fifty eight patients (57%) had developed multiple sclerosis at the time of reassessment in the present study, of whom 51 (88%) had clinically definite disease. This compared with 40% of the original group, in 1978, of whom 62% then had clinically definite multiple sclerosis. When the life-table method of analysis was used, the probability of developing multiple sclerosis was 75%, 15 years after the initial episode of optic neuritis. The frequencies of HLA-DR2 and the recently defined D-region antigen, DQw1, were significantly increased in patients with isolated optic neuritis and those who subsequently developed multiple sclerosis compared with normal controls, but neither allele appears to influence progression from optic neuritis to multiple sclerosis. Patients with optic neuritis who were HLA-DR3 positive had an increased risk for the development of multiple sclerosis (RR = 2.8) and this risk was further enhanced when DR3 occurred in combination with DR2 (RR = 6.7). The overall increased risk of developing multiple sclerosis for patients with this combination was 26 times that for the normal population. When the patients' original tissue-typing was considered BT 101 no longer influenced conversion of optic neuritis to multiple sclerosis. This may partly be explained by improved methods of tissue-typing, since not all BT 101 patients were subsequently found to be positive for HLA-DR2 or HLA-DQw1 and vice versa and by extended follow-up as multiple sclerosis conversion in HLA-DR2 negative individuals increased with time. All 101 patients were typed for Factor B alleles. No significant differences in frequencies were found between individuals with isolated optic neuritis or those who progressed to multiple sclerosis compared with the control population. Recurrent episodes of optic neuritis were associated with an increased risk for the development of multiple sclerosis in this study.     

Multiple Implants for First Molar Prosthodontics

Problems that can occur when single implants are utilized to restore first molar teeth include the frequent loosening of screws, as well as screws and/or implant breakage. These may result from torquing and rotational movements of the prosthesis during masticatory and parafunctional mandibular movements. When sufficient bone and mesio-distal restorative space is present, the placement of two implants should be considered.     

Practical guidelines for action regarding application of CPR/DNR

Technological advances in the field of medicine have resulted in the prolongation of lives that under ordinary conditions would have terminated. Such advances, though calling attention to the wonders of modern technology, are not without significant complications. The injudicious application of extraordinary procedures for extending life highlights problems that affect medical, social, and psychological as well as moral and ethical realms. The complexity of the problems has long since perplexed health/human service practitioners charged with effecting and/or assisting in the implementation of the critical life-death decisions on which this paper focuses.

A systematic strategy is outlined to guide human service providers in making decisions regarding the application or withholding of life-sustaining procedures. Emphasis is placed upon the integrity of self-determination as it relates to competency. Procedures for the incompetent patient are recommended.     

New evidence for a gating action of norepinephrine in central neuronal circuits of mammalian brain

Many previous studies have examined the effects of norepinephrine (NE) on neuronal responsiveness to synaptic inputs and putative transmitter substances and have described differential depressant actions of NE on stimulus evoked versus spontaneous discharge such that the "signal to noise" ratio of threshold responses was increased. In the present studies, similar experimental strategies employing a combination of microiontophoresis, single unit recording and afferent pathway stimulation in intact anesthetized and brain tissue slice preparations have revealed noradrenergic "gating" actions whereby weak or subthreshold synaptic stimuli can evoke threshold neuronal responses in the presence of iontophoretically applied NE or following electrical stimulation of the locus coeruleus. Overall, these results suggest that potentially threshold excitatory and inhibitory synaptic inputs may normally arrive at central neurons but appear weak or absent except during behavioral conditions favoring the synaptic release of NE. As such, these findings provide evidence that signal to noise ratio may not be the only potential modulatory action expressed by NE in noradrenergic target circuits of the mammalian brain.     

Structure-activity relationships for epidermal ornithine decarboxylase induction and skin tumor promotion by anthrones

The present study was designed to compare the skin tumor promotingand epidermal ornithine decarboxylase (ODC) inducing activitiesof various structural analogs of anthralin (1, 8-dihydroxy-9-anthrone)and chrysarobin (1, 8-dihydroxy-3- methyl-9-anthrone). Groupsof 30 SENCAR mice each were initiated with 7, 12-dimethylbenz[a]anthraceneand 2 weeks later promoted with once- or twice-weekly applicationsof various doses of these anthrone derivatives. Carbon-10 (C₁₀)-acylderivatives of anthralin were active skin tumor promoters inthe range of 25–440 nmol per mouse. 10-Acetylanthralinwas significantly more active than 10-myristoyl-anthralin atlow doses (e.g. 25 and 50 nmol per mouse) and nearly as potentas the unsubstituted compound. Higher doses ( 100 nmol per mouse)of this derivative were toxic, hence, reducing the final papillomaresponse. On a relative activity scale where anthralin is 1.0,these derivatives had activities that were 0.7 and 0.2, respectively.10, 10-Dipropylanthralin was totally inactive at the doses tested.C⁶-Substituted derivatives of chrysarobin demonstrated diversetumor promoting activities when tested in the range of 25–440nmol per mouse. On a relative activity scale where chrysarobinis 1.0, 6-methoxychrysarobin (physcion anthrone) was 0.9, whereas6-hydroxychrysarobin (emodin anthrone) had no activity. Chrysophanicacid (1, 8-dihydroxy-3-methyl-9, 10-anthraquinone) was alsoinactive as a tumor promoter at the doses tested. In general,the tumor promoting activities of these anthrone derivativescorrelated very well with their ability to induce epidermalODC after a single topical application indicating an importantrole for this enzyme in skin tumor promotion by anthones. Theability of C₁₀-substituted derivatives of anthralin to undergobase catalyzed oxidation in vitro correlated with both ODC inducingand tumor promoting activities. In addition, copper(II) bis(diisopropylsalicylate)was found to inhibit both ODC induction and skin tumor promotionby chrysarobin. These latter data, when taken together, suggesta role for oxidation at C₁₀ in skin tumor promotion by anthronederivatives.