Influence of the optical axis-to-target view angle on endoscopic task performance

BACKGROUND: The location of the optical port and the choice of endoscope determine the angle subtended between the optical axis of the endoscope and the plane of the operation target: the optical axis-to-target view (OATV) angle. The aim of the study was to investigate the influence OATV angle on endoscopic task performance. METHODS: The Dundee Endoscopic Psychomotor Tester was used for objective assessment of endoscopic task performance. Ten surgeons carried out a standard task with the optical axis of the endoscope subtending 90 degrees, 75 degrees, 60 degrees and 45 degrees to the target surface. Each subject underwent three test sessions. Each session consisted of one run with each of the OATV angles in a random order. The outcome measures were the errors rate, the execution time, and the force applied on the target. RESULTS: The 90 degrees OATV angle had the best accuracy, the shortest execution time, and the lowest force applied on the back plate. The errors rate increased from 17% with the 90 degrees OATV angle to 79% with the 45 degrees angle. There was a significant increase in execution time and force with the decrease in the OATV angle (p < 0.0001). CONCLUSIONS: The best task performance is obtained when the optical axis of the endoscope is perpendicular to the target plane.     

Intracranial extension of inverted papilloma: An unusual and potentially fatal complication

BACKGROUND: The purpose of this article is to define the outcome of intracranial extension of inverted papilloma and outline a rationale for management of this rare clinical presentation. METHODS: A review of patients with intracranial extension of inverted papilloma reported in the literature (18 patients), or treated in our institution (3 patients ) was performed. The data of these 21 patients were consolidated with regard to clinical presentation, treatment, and outcome. Nine patients, including 1 of our cases, had coexisting squamous cell carcinoma and therefore were excluded from the analysis. Twelve patients with "pure" inverted papilloma formed the basis of this study. RESULTS: The majority of patients (83%) with intracranial inverted papilloma had recurrent disease. Patients with extradural disease had a survival rate of 86% with an average follow-up of 4.4 years. Eighty-six percent of these survivors were treated with craniofacial resection. In contrast, 75% of patients with intradural inverted papilloma were dead of disease with an average follow-up of 9.3 months regardless of the treatment modality. CONCLUSIONS: Intracranial extension of inverted papilloma is mostly associated with recurrent disease. Intracranial extradural inverted papilloma can be effectively controlled with craniofacial resection. Intracranial intradural involvement of inverted papilloma has a poor prognosis regardless of treatment. Aggressive treatment of intranasal inverted papilloma may be the most important factor in preventing intracranial presentation.     

Opposite links of positive and negative symptomatology with memory errors in schizophrenia

We wished to confirm and extend a previous correlational study of our group, suggesting that positive symptoms in schizophrenia were linked to an increase in certain types of memory errors, and negative symptoms to a decrease in other types of errors. A post-hoc analysis was conducted in 33 schizophrenic patients and 40 normal control subjects on memory errors collected in a free recall task and two types of recognition tasks. The memory errors were intrusions and list errors in free recall, and decision bias towards false alarms in recognition, all assumed to reflect a source-monitoring failure. In a first analysis, the patient sample was split along the median for positive symptoms as rated by the Scale for the Assessment of Positive Symptoms (SAPS). In a second analysis, it was split along the median for negative symptoms as rated by the Scale for the Assessment of Negative Symptoms (SANS). Patients with high ratings of positive symptoms made more memory errors (intrusions, list errors, false alarms) than those with low ratings, supporting the hypothesis of a link between positive symptomatology and source-monitoring failure. On the other hand, patients with high ratings of negative symptoms made fewer of these errors than the other patients. Fewer errors were specifically associated with more affective flattening, alogia and anhedonia, whereas avolition was entirely unrelated to them.     

Propionibacterium as a cause of postneurosurgical infection in patients with dural allografts: report of three cases

OBJECTIVE AND IMPORTANCE: Although Propionibacterium acnes is a common inhabitant of human skin, it is an uncommon pathogen in postoperative infections. We report three cases of postoperative wound infection/osteomyelitis caused by P. acnes. CLINICAL PRESENTATION: Three patients underwent craniotomy for a supratentorial meningioma and had a dural allograft at the time of closure. The patients presented several weeks after surgery with clinical evidence of a wound infection. INTERVENTION: All patients were diagnosed with P. acnes infection and treated for this pathogen with appropriate antibiotics. The bone flap was removed in two patients. After antibiotic therapy, all patients demonstrated no further evidence of infection. CONCLUSION: To our knowledge, this is the first published report of P. acnes infection in patients with a dural substitute. The source of infection cannot be confidently ascertained; however, two patients had strains of P. acnes from one brand of graft, which were indistinguishable by pulsed field gel electrophoresis typing.     

A current appreciation of sites for pharmacological intervention in allergic conjunctivitis: effects of new topical ocular drugs.

Two important realizations about pathophysiological mechanisms involved in allergic conjunctivitis have led to novel drug discovery efforts and new topical ocular medications for prevention and treatment of this prevent allergic disease. The first of these, interspecies and intraspecies mast cell heterogeneity, was established in the mid-1980's by investigators working in the field of asthma. It is now appreciated that secretory responses as well as effects of pharmacological agents differ depending upon the mast cell population studied. Two types of human mast cells, the tryptase containing (T) and the tryptase/chymase containing (TC) mast cells, have been characterized in a variety of tissues. Significantly, Irani et al. (1) demonstrated by immunohistochemical staining that the mast cells present in conjunctival tissues from patients with allergic conjunctivitis were 100% TC. Functional responses of human conjunctival mast cells to a variety of secretagogues (2) were consistent with their classification as TC or connective tissue type mast cells. Importantly, the studies by Miller et al. mentioned above allowed the harvesting and preparation of human conjunctival mast cells for use in drug screening studies. Utilization of these cells has led to the identification of Patanol, the most effective human conjunctival mast cell stabilizer available for topical use in allergic conjunctivitis (3). These same studies demonstrated the lack of mast cell stabilizing activity for cromolyn and nedocromil in these connective tissue type, TC containing, human conjunctival mast cells. Similar lack of effect was noted with these drugs on human skin mast cell degranulation (4). The second important discovery in the area of allergic conjunctivitis has been the demonstration that conjunctival epithelial cells may contribute to the perpetuation of the allergic response. A report from Gamache et al. (5) identified cytokines produced by human conjunctival epithelial cells following treatment with a number of stimuli. Significantly, Sharif et al. (6) subsequently identified functional histamine H1 receptors on these same cell types. Recently, Weimer et al. (7) have shown that exposure of human conjunctival epithelial cells to histamine leads to the production of pro-inflammatory cytokines IL-6 and IL-8. Importantly, treatment of the epithelial cells with drugs that possess histamine H1 antagonist properties prevents cytokine production. It is noteworthy that first generation anti-histamines antazoline and pheniramine are not potent inhibitors of histamine-stimulated cytokine synthesis in intact epithelial cells, while newer anti-histamines Emadine and levocabastine are more potent. Surprisingly, Patanol was more potent as an inhibitor of histamine-stimulated cytokine production by the epithelial cells than would be predicted from its histamine H1 antagonist affinity. These inhibitory effects on conjunctival epithelial cell production of pro-inflammatory cytokines may contribute to enhanced clinical activity noted with these recently approved drugs.     

Chemotherapy,early surgical reassessment,and hyperfractionated abdominal radiotherapy in stage III ovarian cancer: results of a gynecologic oncology group study

PURPOSE: To determine outcomes and treatment toxicities in patients with optimal (< or = 1 cm residual) Stage III ovarian carcinoma treated with three courses of cisplatin-cyclophosphamide, surgical reassessment (SRA), and hyperfractionated whole abdominal irradiation (WAI). METHODS AND MATERIALS: Forty-two eligible patients entered this prospective Phase II study conducted by the Gynecologic Oncology Group (GOG). Disease characteristics were as follows: age range, 32-76 years (median 58); Stage IIIA (n = 1, 2%), IIIB (n = 2, 5%), IIIC (n = 39, 93%); histology-serous papillary (n = 21, 50%); other (n = 21, 50%); Grade 1 (n = 1, 2%); 2 (n = 14, 33%); 3 (n = 27, 54%); residual disease after initial surgery (present: n = 23, 55%; absent: n = 19, 45%). Five patients progressed while on chemotherapy, could not be effectively cytoreduced, and were not eligible for WAI. Of the remaining 37 patients, 35 received WAI. Surgical reassessment was not performed in five patients. RESULTS: Of 37 patients with known SRA status after chemotherapy, 21 (57%) were grossly positive, 4 (11%) were microscopically positive, and 12 (32%) were negative. Based on measurements recorded following initial laparotomy and surgical reassessment, progression during chemotherapy was noted in 40%, stage disease in 37%, and objective response in 23%. Toxicity during hyperfractionated WAI was limited and reversible. No patient beginning WAI failed to complete or required a significant treatment break. Following WAI, six patients underwent laparotomies for abdominal symptoms; five had recurrent disease. Five additional patients were managed conservatively for small bowel obstruction (SBO) or malabsorption, of whom three subsequently developed recurrence. Twenty-two patients having pelvic boosts were significantly more likely to require management for gastrointestinal morbidity (p = 0.0021). Considering all eligible patients, median disease-free and overall survivals were 18.5 and 39 months, respectively. Considering patients completing chemotherapy and WAI, median disease-free and overall survivals were 24 and 46 months, respectively. CONCLUSIONS: (a) Disease progression occurred within three cycles of cisplatin and cyclophosphamide chemotherapy in 40% of patients with optimal (< or = 1 cm residual) Stage III ovarian carcinoma. (b) Following limited chemotherapy, hyper-fractionated WAI was acutely well tolerated. (c) Late radiation-related toxicity was observed in only three patients (8.6%) in the absence of recurrent disease. Late gastrointestinal morbidity was significantly associated with the administration of a pelvic radiotherapy (RT) boost. (d) Short duration chemotherapy followed by SRA and hyperfractionated WAI without a pelvic boost is a promising management option for patients with optimal Stage III ovarian cancer. A Phase III trial will be necessary to determine how this treatment strategy compares with chemotherapy or RT alone in this patient population.     

Modification of naloxone-precipitated withdrawal symptoms in mice by drugs acting on alpha(2)-adrenoceptors

Modification of naloxone-precipitated withdrawal symptoms by drugs acting on alpha-adrenoceptors was investigated in morphine-dependent mice. Clonidine (0.05-1mg/kg) attenuated most withdrawal symptoms, but potentiated withdrawal hypothermia. Jumping was attenuated by doses of clonidine up to 0.3mg/kg, but markedly potentiated by 1mg/kg. Prazosin (0.05mg/kg) neither had effects of its own, nor influenced those of clonidine. Both yohimbine (0.05-5mg/kg) and idazoxan (1-10mg/kg) potentiated naloxone-precipitated withdrawal symptoms. When tested against a low dose of clonidine (0.2mg/kg), idazoxan dose-dependently reduced the suppressive effects of clonidine on jumping, "wet dog" shakes, burrowing and body-weight loss but potentiated the hypothermic response of clonidine. Yohimbine similarly reduced the suppressive effect of clonidine on body-weight loss and potentiated its hypothermic response, but unlike idazoxan, it did not influence the inhibition by clonidine of "wet dog" shakes, and markedly reversed the suppression of jumping and burrowing into potentiation. Yohimbine and idazoxan also differed with respect to their antagonistic profile against a high dose of clonidine (1mg/kg). Yohimbine further aggravated the potentiation of jumping by clonidine, reduced the effect on body-weight loss and reversed the suppression of burrowing by clonidine. On the other hand, idazoxan markedly reduced the potentiation of jumping by clonidine, and reversed its effect on "wet dog" shakes and burrowing. These findings indicate that clonidine has a biphasic effect on jumping, and disclose differences in the antagonistic profiles between yohimbine and idazoxan. The results suggest that in addition to alpha(2)-adrenoceptors, non-adrenergic imidazoline receptors sensitive to clonidine and idazoxan but not to yohimbine may modulate the expression of morphine withdrawal symptoms.     

Effect of dietary butylated hydroxyanisole on the mouse hepatic monooxygenase system of nuclear and microsomal fractions

The effect of butylated hydroxyanisole (BHA) administrationon the hepatic monooxygenase system of nuclear and microsomalfraction was investigated in male mice. Addition of BHA to thediet significantly lowered the content of cytochrome P-450 inliver nuclei and increased the specific activity of NADPH-cytochromec reductase and the content of cytochrome b₅ in liver microsomes.Incubation of benzo[a]pyrene (BP) with liver nuclei from BHA-fedmice resulted in inhibition of binding of BP metabolites tonuclear macromolecules by 50% compared with control. However,there was no effect of BHA on the binding of BP metabolitesto macromolecules when BP was incubated with added DNA and livermicrosomes from BHA-fed mice. It has been postulated that modificationof nuclear monooxygenases by BHA may play a role in the inhibitoryeffect of BHA on BP carcinogenesis.     

The effect of growth hormone on the growth failure of chronic renal failure

To investigate the effects of growth hormone (GH) on the reversal of growth failure in uremia, recombinant human GH (rhGH) was administered to rats with chronic renal failure (CRF). The dosage of rhGH was 3 IU/day (i.p.) for 13 days after the induction of CRF by 5/6 nephrectomy. Animals were classified into four groups: untreated nephrectomized rats (NX,n=40), GH-treated nephrectomized rats (NX+GH,n=18), sham-operated rats fed ad libitum (SHAMAL,n=27), and sham-operated rats pair-fed with 10 NX rats (SHAMPF,n=10). NX and NX+GH rats developed a similar and moderate degree of CRF, serum urea nitrogen being (mean±SEM) 49±3 and 54±4 mg/dl, respectively, compared with 16±4 and 19±0 mg/dl in SHAMAL and SHAMPF groups. Weight (56.0±3.3 g) and length (3.5±0.1 cm) gains of NX rats were lower than those of SHAMAL rats (94.2±4.0 g,P<-0.0001 and 4.1±0.2 cm,P<-0.01). Growth of the SHAMPF group and the matched NX rats was not significantly different. Weight (56.2±5.0 g) and length (3.4±0.2 cm) gains of NX+GH and NX rats were similar, the beneficial effect of GH therapy on growth being observed in only those animals with more severe degrees of uremia. This growth-promoting action resulted from greater food efficiency and not from stimulated food intake. The hypercholesterolemia seen in NX rats, 81±2 mg/dl versus 55±3 mg/dl in SHAMAL (P0.0001), was not increased in the NX+GH group, 87±3 mg/dl. There was a positive and significant correlation between serum cholesterol and serum urea nitrogen values in NX and NX+GH animals. This study suggests that growth impairment of mild CRF is mainly due to malnutrition and is refractory to GH administration. GH therapy improves the growth rate of animals with advanced CRF without aggravating their lipid abnormalities.