Treatment of the abdominal aorta combined with a second surgical procedure

The synchronous performance of aortic graft with a second surgical procedure should be avoided because of the risk of subsequent graft infection. The Authors reported the experience of 21 patients who underwent synchronous aortic graft with second surgical procedure. No graft infection occurred and it is concluded that such combined operation may be safer to perform than staged surgery in elderly patients.     

Immunotherapy I: Cytokine gene transfer strategies

The cytokine approach to gene therapy of cancer stems from early studies of direct, repeated injection of recombinant cytokines at the tumor site, and extension of the bystander effect that enables a few cytokine gene transduced cells in a tumor to bring about its total destruction. This effect can be extended through the immune system, since cytokine-activated regression of a small mass of tumor cells can afford systemic protection. Transduced cells used as a vaccine provide a local concentration of both cytokine and tumor antigens. Cytokines sustain antigen uptake and presentation by increasing the immunogenic potential of the environment through the recruitment of antigen presenting cells and leukocytes, and activation of a cascade of events which amplify and tone up the efficacy of a vaccine. The promises and difficulties of this approach are discussed by considering what is still missing from experimental studies and what can best be done as soon as possible in animals and humans to reach compelling conclusions.     

Corrigendum

M. Maneo should read A. Maneo. The author's correct affiliationis III Clinica Ostetrico Ginecologica, Università diMilano, Milan, Italy.     

Total sleep deprivation combined with lithium and light therapy in the treatment of bipolar depression: replication of main effects and interaction

The clinical usefulness of total sleep deprivation (TSD) in the treatment of bipolar depression is hampered by a high-rate short-term relapse. Previous literature has suggested that both long-term lithium treatment and light therapy could successfully prevent relapse. We randomized 115 bipolar depressed inpatients to receive three cycles of TSD, alone or in combination with morning light exposure, given at an intensity of 150 or 2500 lux. Forty-nine patients were undergoing long-term treatment with lithium salts (at least 6 months), while 66 patients were taking no psychotropic medication. Mood was self-rated by the Visual Analogue Scale three times a day during treatment. The results showed that both light therapy and ongoing lithium treatment significantly enhanced the effects of TSD on the perceived mood, with no additional benefit when the two treatments were combined. Subjective sleepiness during TSD, as rated by the self-administered Stanford Sleepiness Scale, was significantly reduced by light exposure, and was correlated with the outcome. This study confirms the possibility of obtaining a sustained antidepressant response to TSD in bipolar patients.     

Sequential endo-laparoscopic treatment in patients with common bile calculi

BACKGROUND: Laparoscopic treatment of common bile duct (CBD) stones is gaining great acceptance worldwide, but actually it requires skills and technologies too expensive for a great part of general surgeons. So endoscopic removal of CBD stones before cholecystectomy is usually performed. Since 1991 in our department we started a policy of selective preoperative cholangiopancreatography (ERCP) in patients suspected for choledocholithiasis and waiting for laparoscopic cholecystectomy. METHODS: A retrospective study has been made on a population of 1100 patients who underwent elective laparoscopic cholecystectomy in the period between January 1991 and December 1997. They were 391 male and 719 female with a mean age of 52 years, 126 of whom (11.5%) were selected to have ERCP preoperatively because they had clinical, biochemical and ultrasound signs of the presence of common bile duct stones (CBDS). RESULTS: Successful cannulation of the CBD was achieved in 124 cases (98.4%), with failures due to ampullary diverticula. In 7 cases (5.5%) a precut was necessary to obtain cannulation. Sphincterotomy was performed in 113 patients (89.7%). In 93 patients (73.8%) stones were found (87 macrolithiasis and 6 microlithiasis); in 91 (97.8%) stones were removed in one (87) or two (4) endoscopic session. There were 2 major complications (one bleeding and one severe pancreatitis) due to ERCP or a sphincterotomy. Two patients developed symptoms from unsuspected common bile duct stones after LC and were removed endoscopically. No complications during LC were due to ERCP or ES. CONCLUSIONS: Selective preoperative ERCP is an effective way of clearing the CBD stones before laparoscopic cholecystectomy, with low rate of complications related to endoscopic and laparoscopic procedures, and short mean hospital stay (5.5 days), according to the concept of minimally invasive treatment.     

A model of electrical excitation of the mammalian auditory-nerve neuron

A model of the mammalian auditory-nerve neuron has been developed based on the classical work of Frankenhauser and Huxley [(1964) J. Physiol. 171, 302-315], modified by McNeal [(1976) IEEE Trans. Biomed. Eng. BME-23, 329-336], and Reilly et al. [(1985) IEEE Trans. Biomed. Eng. BME-32, 1001-1011], and fine tuned to represent physiological data obtained from single auditory-nerve fiber experiments in squirrel monkeys. The model is capable of reproducing neural action potential waveforms due to electrical stimulation, and can reliably predict action potential thresholds and strength-duration curves. This paper explains the derivation of the mathematical model and the effects of varying certain independent parameters including fiber diameter, length of the nodes of Ranvier, internodal length, and myelin thickness. The model parameters were selected according to the anatomical findings of Liberman and Oliver [(1984) J. Comp. Neurol. 223, 163-176], and Liberman (Pers. Commun.). The length of the unmyelinated termination of the auditory-nerve that survives after aminoglycoside damage to the inner ear has not been experimentally determined. Therefore, it was investigated as an independent variable in the model. An unmyelinated terminal length of 10.0 micron was found to most accurately describe the experimental neural strength-duration curves obtained from aminoglycoside-deafened squirrel monkeys. The parameter that had the next most significant effect on the model was fiber diameter which affects all conduction pathways, across the membrane and through the fiber. Finally the results of the model are compared with behavioral data obtained from patients and monkeys implanted with cochlear prostheses. In the companion paper [(1987) Hear. Res. 31, 267-286] predictions of the model are quantitatively compared with single-neuron data from squirrel monkeys.     

COVID-19 and Guillain-Barré syndrome: A single-center prospective case series with a 1-year follow-up

Single reports of Guillain-Barré syndrome (GBS) have been reported worldwide during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. While case reports are likely to be biased toward uncommon clinical presentations, systematic assessment of prospective series can highlight the true clinical features and spectrum. In this prospective, observational study, we included all consecutive patients who developed GBS. In patients with SARS-CoV-2 infection as antecedent, the time-gap between the infection and GBS onset had to be ≤30 days. The referral was a neurological University Research Hospital, in the Italian Region more severely involved by the pandemic, and hospitalizing both COVID+ and non-COVID neurological diseases. Clinical, laboratory, cerebrospinal fluid, and electromyographic features of GBS diagnosed between March 2020 and March 2021 were compared to a retrospective series of GBS diagnosed between February 2019 and February 2020 (control population). Nasopharyngeal swab was still positive at GBS onset in 50% of patients. Mild-to-moderate COVID-related pneumonia, as assessed by X-ray (6 patients) or X-ray plus computerized tomography (2 patients) co-occurred in 6 of 10 patients. GBS diagnosed during the pandemic period, including 10 COVID-GBS and 10 non–COVID-GBS, had higher disability on admission (P = .032) compared to the GBS diagnosed between February 2019 and 2020, possibly related to later hospital referral in the pandemic context. Compared to non–COVID-GBS (n = 10) prospectively diagnosed in the same period (March 2020–2021), post–COVID-GBS (n = 10) had a higher disability score on admission (P = .028), lower sum Medical Research Council score (P = .022) and lymphopenia (P = .025), while there were no differences in GBS subtype/variant, severity of peripheral involvement, prognosis and response to treatment. Cerebrospinal fluid search for SARS-CoV-2 RNA and antiganglioside antibodies were negative in all COVID+ patients. Temporal clustering of cases, coinciding with the waves of the pandemic, and concomitant reduction of the incidence of COVID-negative GBSs may indicate a role for SARS-CoV-2 infection in the development of GBS, although the association may simply be related to a bystander effect of systemic inflammation; lack of prevalence of specific GBS subtypes in post–COVID-GBS also support this view. GBS features and prognosis are not substantially different compared to non–COVID-GBS.     

Alteration of Elastin, Collagen and their Cross-links in Abdominal Aortic Aneurysms

OBJECTIVES: although the mechanism of arterial dilation and aneurysm development has not been clarified, the degradation of elastin and collagen plays undoubtedly a critical role. We evaluated the elastin and collagen content through the detection of their cross-links in aneurysmal and non-aneurysmal abdominal aortic walls. MATERIALS AND METHODS: in 26 human abdominal aortic aneurysm specimens obtained during surgery and in 24 autopsy control samples of non-aneurysmal abdominal aorta the tissue content of elastin and collagen cross-links were measured by HPLC. Collagen was also detected by evaluating two characteristic amino acids, 4-hydroxyproline (4-hypro) with a colorimetric method and 5-hydroxylysine (5-hylys) by gas chromatography. RESULTS: significantly fewer elastin cross-links were found in aneurysm samples compared to controls (desmosines and isodesmosines: 90% reduction; p<0.01). The opposite was true for pyridinoline collagen cross-links (350% increase) and deoxypyridinolines (100% increase, p=0.01). Tissue content of 5-hylys, 4-hypro and total amino acids were reduced significantly by 50% in aneurysmal samples. CONCLUSIONS: beside confirming decreased elastin content in aneurysmal walls, these results show a concurrent increase of collagen cross-links. Since total collagen markers were decreased (decreased 4-hypro and 5-hylys) it is reasonable to suggest that in aneurysmal aortic walls old collagen accumulates cross-links while new collagen biosynthesis is somehow defective.