The effect of morphine administration on GluN3B NMDA receptor subunit mRNA expression in rat brain

Opioid addiction is critically dependent on the activation of N‑methyl‑D‑aspartate (NMDA) receptors, which are widely found in the mesocorticolimbic system. Meanwhile, opioid addiction may affect the expression level of NMDA receptor subunits. The existence of GluN3 subunits in the NMDA receptor's tetramer structure reduces the excitatory current of the receptor channel. We evaluated the changes in the mRNA expression pattern of the GluN3B subunit of the NMDA receptor in rat brains following acute and chronic exposure to morphine. Chronic, escalating intraperitoneal doses of morphine or saline were administered twice daily to male Wistar rats for six days. Two other groups were injected with a single acute dose of morphine or saline. The mRNA level of the GluN3B subunit of the NMDA receptor in the striatum, hippocampus, and nucleus accumbens (NAc) was measured by real‑time PCR. mRNA expression of the GluN3B subunit was considerably augmented (3.15 fold) in the NAc of animals chronically treated with morphine compared to the control group. The difference between rats that were chronically administered morphine and control rats was not statistically significant for other evaluated brain areas. In rats acutely treated with morphine, no significant differences were found for GluN3B subunit expression in the examined brain regions compared to the control group. It was concluded that chronic exposure to morphine notably increased the GluN3B subunit of the NMDA receptor in NAc. The extent of the impact of this finding on opioid addiction and its features requires further evaluation in future studies.

Evaluation of the efficacy of N-acetylcysteine and bromhexine compared with standard care in preventing hospitalization of outpatients with COVID-19: a double blind randomized clinical trial

INTRODUCTION AND AIM

Since its emergence in December 2019, the coronavirus disease caused by the severe acute respiratory syndrome coronavirus 2 has become a global emergency, spreading rapidly worldwide. In response to the early referral of these patients to outpatient health centers, we decided to seek more effective treatments in the early stages of their referral. This study aims to prevent both the progression and deterioration of the physical conditions of COVID-19 patients, reduce the rate of referrals, and mitigate the risks of hospitalization and death.

MATERIAL AND METHODS

Conducted at Dibaj Therapeutic Center, Hamadan City, Iran, a double-blind randomized controlled trial encompassed 225 COVID-19 patients from April to September 2022. Ethical approval was obtained from Hamadan University of Medical Sciences (Approval No.: IR.UMSHA.REC.1400.957), with the protocol registered in the Iranian Registry of Clinical Trials (Registration No. : IRCT20220302054167N1). In this study, we included patients who tested positive for COVID-19- PCR and were symptomatic, excluding those who were pregnant or had received a COVID-19 vaccine. Patients with oxygen saturation above 92% were allocated to three groups: Group A received N-acetylcysteine, Group B received Bromhexine, and Group C received standard care. Follow-ups on oxygen levels, symptoms, and hospitalization needs were conducted on days 7 and 14, with hospitalized patients monitored for one month post-hospitalization.

RESULTS

The study found that both N-acetylcysteine and Bromhexine can effectively reduce hospitalization rates and mortality and shorten the duration of hospitalization. The third visit of patients who received N-acetylcysteine showed an increase of 1.33% in oxygen saturation compared to their first visit, and in patients who received Bromhexine, this increase was 1.19%. The mortality rate was 9.33% in the control group and zero in both groups of patients who received medication.

CONCLUSION

In conclusion, the results of this study indicate that NAC and bromhexine may be effective in the treatment of patients with positive COVID-19, with a lower hospitalization rate, shorter hospitalization, faster recovery time, and reduced mortality compared to the control group.

Relationship between Lifestyle and Frailty among Iranian Community-Dwelling Older Adults: Pilot Study

Background

Aging affects physical, mental, and social functions, which can lead to an increase in frailty. Old adults with frailty syndrome are prone to disabilities and hospitalization. Lifestyle is a context-based factor that has the potential to prevent frailty.

Objectives

This study aimed to assess the relationship between lifestyle and frailty among Iranian community-dwelling older adults.

Design Setting

This is a descriptive-analytical cross-sectional study. The participants were 513 older adults over 60 years by the convenience sampling method from the retirement center.

Measurements

Data were collected using Tilberg's frailty index, the Iranian elderly lifestyle questionnaire, and the Mini-Cog test. Data were analyzed with SPSS v.26 software by chi-square and logistic regression tests.

Results

The age of the participants was 66.43 ± 4.69 years. The male-to-female sex ratio was 1.5 (39.2% women). The lifestyle of 96 (19.3%) old adults was unfavorable. 18.7 percent of older adults had Frailty syndrome. The logistic regression test showed that moderate and favorable lifestyle (OR= 0.06; 95% CI: 0.02-0.16), age over 75 years (OR= 5.25; 95% CI: 2.35-11.69), retired employment status (OR= 0.13; 95% CI: 0.29-0.05) are factors that have a significant relationship with frailty (P< 0.05).

Conclusion

The findings showed that lifestyle can predict frailty. Therefore, it seems that an optimal lifestyle can prevent the frailty of older adults.

Mesenchymal stem cells (MSCs) and MSC-derived exosomes in animal models of central nervous system diseases: Targeting the NLRP3 inflammasome

The NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3) inflammasome is a multimeric protein complex that is engaged in the innate immune system and plays a vital role in inflammatory reactions. Activation of the NLRP3 inflammasome and subsequent release of proinflammatory cytokines can be triggered by microbial infection or cellular injury. The NLRP3 inflammasome has been implicated in the pathogenesis of many disorders affecting the central nervous system (CNS), ranging from stroke, traumatic brain injury, and spinal cord injury to Alzheimer's disease, Parkinson's disease, epilepsy, multiple sclerosis, and depression. Furthermore, emerging evidence has suggested that mesenchymal stem cells (MSCs) and their exosomes may modulate NLRP3 inflammasome activation in a way that might be promising for the therapeutic management of CNS diseases. In the present review, particular focus is placed on highlighting and discussing recent scientific evidence regarding the regulatory effects of MSC-based therapies on the NLRP3 inflammasome activation and their potential to counteract proinflammatory responses and pyroptotic cell death in the CNS, thereby achieving neuroprotective impacts and improvement in behavioral impairments.

The effect of induced hypertension in aneurysmal subarachnoid hemorrhage: A narrative review

Aneurysmal subarachnoid hemorrhage ‎(aSAH) ‎accounts for 2-5% of all strokes, and 10%-15% of ‎aSAH patients will not survive until hospital admission. Induced hypertension (IH) is an emerging therapeutic option being used for the treatment of vasospasm in ‎aSAH. For patients with cerebral vasospasm (CVS) consequent to SAH, IH is implemented to increase systolic blood pressure (SBP) in order to optimize cerebral blood flow (CBF) and prevent delayed cerebral ischemia (DCI). Prophylactic use of IH has been associated with the development of vasospasm and cerebral ischemia in SAH patients. Various trials have defined several different parameters to help clinicians decide when to initiate IH in a SAH patient. However, there is insufficient evidence to recommend therapeutic IH in aSAH due to the possible serious complications like myocardial ischemia, development of posterior reversible encephalopathy syndrome (PRES), pulmonary edema, and even rupture of another unsecured aneurysm. This narrative review showed the favorable impact of IH therapy on aSAH patients; however, it is crucial to conduct further clinical and molecular experiments to shed more light on the effects of IH in aSAH.

Potential biomarkers of addiction identified by real-time PCR in human peripheral blood lymphocytes: a narrative review

Addiction-related neurobiological factors could be considered as potential biomarkers. The concentration of peripheral biomarkers in tissues like blood lymphocytes may mirror their brain levels. This review is focused on the mRNA expression of potential addiction biomarkers in human peripheral blood lymphocytes (PBLs). PubMed, EMBASE, Web of Science, Scopus and Google Scholar were searched using the keywords 'addiction', 'biomarker', 'peripheral blood lymphocyte', 'gene expression' and 'real-time PCR'. The results showed the alterations in the regulation of genes such as dopamine receptors, opioid receptors, NMDA receptors, cannabinoid receptors, α-synuclein, DYN, MAO-A, FosB and orexin-A as PBLs biomarkers in addiction stages. Such variations could also be found during abstinence and relapse. PBLs biomarkers may help in drug development and have clinical implications.

Paroxysmal sympathetic hyperactivity during traumatic brain injury

Traumatic brain injury (TBI) is one of the leading causes of disability, morbidity, and mortality worldwide. Some of the more common etiologies of TBI include closed head injury, penetrating head injury, or an explosive blast head injury. Neuronal damage in TBI is related to both primary injury (caused by mechanical forces), and secondary injury (caused by the subsequent tissue and cellular damages). Recently, it has been well established that Paroxysmal Sympathetic Hyperactivity (PSH), also known as "Sympathetic Storm", is one of the main causes of secondary neuronal injury in TBI patients. The clinical manifestations of PSH include recurrent episodes of sympathetic hyperactivity characterized by tachycardia, systolic hypertension, hyperthermia, tachypnea with hyperpnea, and frank diaphoresis. Given the diverse manifestations of PSH and its notable impact on the outcome of TBI patients, we have comprehensively reviewed the current evidence and discussed the pathophysiology, clinical manifestations, time of onset and duration of PSH during TBI. This article reviews the different types of head injuries that most commonly lead to PSH, possible approaches to manage and minimize PSH complications in TBI and the current prognosis and outcomes of PSH in TBI patients.

Central nervous system manifestations in COVID-19 patients: A systematic review and meta-analysis

BACKGROUND

At the end of December 2019, a novel respiratory infection, initially reported in China, known as COVID-19 initially reported in China, and later known as COVID-19, led to a global pandemic. Despite many studies reporting respiratory infections as the primary manifestations of this illness, an increasing number of investigations have focused on the central nervous system (CNS) manifestations in COVID-19. In this study, we aimed to evaluate the CNS presentations in COVID-19 patients in an attempt to identify the common CNS features and provide a better overview to tackle this new pandemic.

METHODS

In this systematic review and meta-analysis, we searched PubMed, Web of Science, Ovid, EMBASE, Scopus, and Google Scholar. Included studies were publications that reported the CNS features between 1 January 2020 and 20 April 2020. The data of selected studies were screened and extracted independently by four reviewers. Extracted data analyzed by using STATA statistical software. The study protocol registered with PROSPERO (CRD42020184456).

RESULTS

Of 2,353 retrieved studies, we selected 64 studies with 11,687 patients after screening. Most of the studies were conducted in China (58 studies). The most common CNS symptom of COVID-19 was headache (8.69%, 95%CI: 6.76%-10.82%), dizziness (5.94%, 95%CI: 3.66%-8.22%), and impaired consciousness (1.90%, 95%CI: 1.0%-2.79%).

CONCLUSIONS

The growing number of studies has reported COVID-19, CNS presentations as remarkable manifestations that happen. Hence, understanding the CNS characteristics of COVID-19 can help us for better diagnosis and ultimately prevention of worse outcomes.

Prediction of Hospitalization Length. Quantile Regression Predicts Hospitalization Length and its Related Factors better than Available Methods

BACKGROUND

Length of hospitalization is one of the most important indices in evaluating the efficiency and effectiveness of hospitals and the optimal use of resources. Identifying these indices' associated factors could be useful. This study aimed to investigate effective factors of the length of hospitalization in Zanjan teaching hospitals in 2018 using the Quantile regression model.

METHODS

This cross-sectional study was conducted on 1,031 patients. The study population consisted of patients in orthopaedic, pediatric, internal, surgical and intensive care units. The samples were selected by multistage random sampling. The information was collected by a pre-designed checklist. The Quantile regression model and ordinary regression model were performed on the data.

RESULTS

Of the 1,031 patients admitted to different units, 624 (60.52%) were male. Mean and standard deviation of length of hospitalization for men, women and all patients were 7.25±5.48, 8.09±6.35 and 7.58±5.83 respectively. For 90 percent of patients the length of hospitalization was less than 14 days. Twenty-five percent of patients in pediatric and orthopedic units and ten percent of patients in internal and surgery units were hospitalized less than three days. In all quantiles, patients' length of hospitalization in surgery and orthopedic units, compared to the intensive care unit, and patients hospitalized for injuries and poisonings compared to other causes, had a statistically significant difference. (p<0.05).

CONCLUSION

Due to the heterogeneity (skewness) of the length of hospital stay in different units of the hospital, the quantile regression model predicts the length of hospital stay more precisely than the ordinary regression models.

Expression of NMDA receptor subunits in human blood lymphocytes: A peripheral biomarker in online computer game addiction

Background and aims Repeated performance of some behaviors such as playing computer games could result in addiction. The NMDA receptor is critically involved in the development of behavioral and drug addictions. It has been claimed that the expression level of neurotransmitter receptors in the brain may be reflected in peripheral blood lymphocytes (PBLs). Methods Here, using a real-time PCR method, we have investigated the mRNA expression of GluN2A, GluN2D, GluN3A, and GluN3B subunits of the NMDA receptor in PBLs of male online computer game addicts (n = 25) in comparison with normal subjects (n = 26). Results Expression levels of GluN2A, GluN2D, and GluN3B subunits were not statistically different between game addicts and the control group. However, the mRNA expression of the GluN3A subunit was downregulated in PBLs of game addicts. Discussion and conclusions Transcriptional levels of GluN2A and GluN2D subunits in online computer game addicts are similar to our previously reported data of opioid addiction and are not different from the control group. However, unlike our earlier finding of drug addiction, the mRNA expression levels of GluN3A and GluN3B subunits in PBLs of game addicts are reduced and unchanged, respectively, compared with control subjects. It seems that the downregulated state of the GluN3A subunit of NMDA receptor in online computer game addicts is a finding that deserves more studies in the future to see whether it can serve as a peripheral biomarker in addiction studies, where the researcher wants to rule out the confusing effects of abused drugs.

The additive effect of excimer laser on non-cultured melanocyte-keratinocyte transplantation for the treatment of vitiligo: a clinical trial in an Iranian population

BACKGROUND

Non-cultured cellular grafting is specified for stable vitiligo treatment as a novel surgical technique, however, the additive effect of excimer laser on melanocytes-keratinocytes transplantation (MKT) have not experienced yet.

OBJECTIVE

To assay the additive effect of excimer laser on MKT for the treatment of vitiligo in an Iranian population.

METHODS AND MATERIALS

In this non-randomized clinical trial, 39 patches were evaluated. Nine patches treated by MKT alone, 10 patches treated by MKT and excimer laser, 10 patches treated with excimer alone and 10 patches left without any treatments as control patches.

RESULTS

In the patches treated with excimer, the percentage reduction of depigmented area from baseline varied, ranging from 0 to 43.9%. In the nine patches treated with non-cultured MKT, the median percentage reduction of depigmented area from baseline was 15.9%. The median percentage reduction of depigmented area in excimer + MKT was 41.9% .In the untreated patches, the median percentage reduction of depigmented area was 0.1%. After controlling for the effect of 'depigmented area at baseline', significant reductions were observed in depigmented area of the patches treated with combination therapy of excimer and non-cultured MKT in comparison with the other therapies and untreated patches.

CONCLUSION

Although pigmentation in our patients was lower than previous reports from Iran and other countries, however, we signified adding excimer to MKT increased the pigmentation rate in treated patches. Further investigations are recommended with longer follow-up and larger series to validate the findings reported here.

Chaperone potential of Pulicaria undulata extract in preventing aggregation of stressed proteins

This study examined the effect of an aqueous extract of Pulicaria undulata on the 1,4-dithiothreitol (DTT)-induced aggregation of proteins. The effects of the chaperone properties of P. undulata extract on protein aggregation were determined by measuring light scattering absorption, fluorescence, and circular dichroism (CD) spectroscopy. The aqueous extract of P. undulata possesses good chaperone properties but the protection effect was varied in different protein. The extract showed a higher level of protection in high molecular weight proteins than in those of low molecular weight. Using a fluorescence study, the present study provides information on the hydrophobic area of proteins interacting with the P. undulata extract. In fact, by increasing the concentration of the P. undulata extract, the hydrophic area of the protein decreased. CD spectroscopy also revealed that DTT caused changes in both the tertiary and the secondary structure of the proteins, while in the presence of P. undulata extract, there was little change. Our finding suggests the possibility of using P. undulata extract for the inhibition of aggregation and the deposition of protein in disease.

Repair of iatrogenic large colon perforation using laparoscopic methods. Case report and review of the literature

Iatrogenic perforation of the colon during elective colonoscopy is a serious complication. Surgical treatment remains the standard of care. We report a patient with a large colonic perforation that occurred during a screening colonoscopy, successfully repaired with laparoscopic methods. Although the safety and efficacy of this approach is not entirely established, laparoscopy can be used to treat iatrogenic colonic perforation when the defect is readily recognized, easily accessible for closure and the bowel preparation is excellent. A laparoscopic approach to treat iatrogenic colon perforation results in decreased morbidity and hospital stay, in addition to a shorter incision length compared to an open method. In those cases where it is feasible and the surgical skill exists, a laparoscopic attempt at colon repair should probably be the initial clinical approach..

In vitro detection of simulated apical root perforation with two electronic apex locators

INTRODUCTION

The aim of this study was to evaluate the accuracy of two electronic apex locators (Smarpex and NovApex) in detecting apical perforation.

MATERIALS AND METHODS

After access cavity preparations, the working length was determined by the first examiner before and after perforation with a stereomicroscope by introducing a K-file size 10 into the canal and size 25 K-file up to the perforation site, respectively. The specimens were embedded in a 17-well plastic box containing alginate. The root canals were irrigated with chlorhexidine 0.2% (CHX) through a 27-gauge needle. Two examiners measured the root canal length twice and the mean value was calculated. The data were analyzed using Kolmogorov-Smirnov and ANOVA tests.

RESULTS

The results obtained with each Electronic Apex Locator were compared with the corresponding control length. The statistical analysis showed reliable accuracies in detecting the perforation site for the two experimental electronic apex locators (60% and 80% for NovApex and Smarpex, respectively).

CONCLUSION

Although no significant difference was shown between Smarpex and NovApex, these results suggest that electronic apex locators can effectively and reproducibly detect root canal perforations.

Serum Interleukin-6 as a Serologic Marker of Chronic Periapical Lesions: A Case-control Study

Background and aims

Chronic periapical disease with pulpal origin is an inflammatory condition caused by bacterial infection. Chronic infection could affect general health by increasing the production of cytokines such as interleukin-6 (IL-6) that probably play a role in pathogenesis of pulpal and periapical diseases. The aim of the present study was a comparative evaluation of the level of serum IL 6 in patients with periapical lesions and healthy controls.

Materials and methods

This analytical case-control study included 40 patients with chronic peri-apical lesions and 40 individuals without any oral diseases. All of the participants were in good general health. After obtaining an informed consent, clinical and radiographic examinations were carried out and blood samples were collected. Serum IL-6 was measured using ELISA. Data were analyzed using t-test by SPSS 14.0 computer software.

Results

Serum IL-6 concentration was significantly higher in test group compared to the controls (P < 0.05).

Conclusion

The results of the present study indicate that IL-6 produced in periapical lesions may serve as a marker of pathologic inflammatory activities in chronic periapical lesions.

Root Canal Configuration of One-rooted Mandibular Canine in an Iranian Population: An In Vitro Study

Background and aims

A perfect endodontic treatment necessitates proper understanding of the morphology of canal and pulpal variations. This in vitro study was conducted to demonstrate the in-ternal anatomy of mandibular canine teeth in an Iranian population.

Materials and methods

The samples consisted of 100 extracted mandibular permanent canines. The roots of the teeth were molded in acrylic boxes. The crowns of the teeth were cut and 2 mm cross sections were made from CEJ to the apex. Sections were examined using stereomicroscope to reveal the number and location of root canals.

Results

From 100 evaluated teeth, 12 (12%) had 2 canals from which 5 had type II canal configu-ration and 7 (7%) had type III. 88% of the specimens had one canal and none were seen to be of type IV.

Conclusion

The findings of this study emphasize the importance of dentist’s knowledge of varia-tions in root canal morphology, since leaving a canal untreated is one of the main reasons of endodontic failures. When treating mandibular canines, the existence of a second canal should be taken into consideration.

A simple and practical method in treatment of ingrown nails: splinting by flexible tube

BACKGROUND

The ingrown nail (or onychocryptosis) is a common problem that occurs mostly in the big toe and causes high amounts of morbidity in affected patients. Many therapeutic methods have been described, most of them leading to severe damage to the nail or to frequent relapses. The nail splinting technique is a successful, simple and non-invasive therapeutic method for treating ingrown nails.

OBJECTIVE

To determine efficacy of the plastic tube insertion technique in patients with ingrown toenail and its use as a standard treatment.

MATERIALS AND METHODS

We encountered 32 cases (age range 9-67 years) of ingrown toenails in this clinical trial. All of the patients were treated using the plastic nail tube insertion technique for 7 to 15 days. Patients were examined daily for the first 3 days of treatment and were evaluated 3 and 6 months after treatment. All patients were followed up by a single observer.

RESULTS

Recurrence was seen in only two patients after 6 months of treatment (6.25%).

CONCLUSION

The low recurrence rate using the nail splinting technique in the treatment of ingrown toenail, as well as its simple application, shows that this treatment constitutes an effective, non-invasive method. It appears that this technique can substitute other more invasive surgical methods, particularly in the early stages of this disease.

Comparison of cytotoxicity of three dentin bonding systems with two thicknesses of dentin barrier on l929 cell line

INTRODUCTION

Along with introduction of dentin bonding agents (DBA), their clinical use as lining materials is increasing rapidly. Since remaining dentinal thickness (RDT) has always been a concern for cytopathic effect of restorative materials, its effect on reduction of cytotoxicity of these materials especially DBAs is critical. The purpose of this study was to evaluate and compare the cytotoxicity of three dentin bonding systems, belonged to the 4(th), 5(th) and 6(th) generation of DBAs on L929 cell line.

MATERIALS AND METHODS

Thirty human premolar teeth were included. Class I cavity preparations were prepared on occlusal surfaces. After crown separation, a flat dentinal surface was provided and RDT (remaining dentinal thickness) was adjusted at 0.5 and 1.5 mm. Then, cavities were treated in three groups with experimental DBAs: Group 1: Scotchbond multipurpose, Group 2: Excite, Group 3: AdheSE. Blue inlay wax sealed the cavities. Crowns were immersed in culture medium for 24 hours and the cytotoxicity of the resultant toxic medium was measured quantitatively with MTT assay in 4 serial dilutions. Data were analyzed with ANOVA and Tukey's test at 95% significance level.

RESULTS

MTT assay determined that only in neat dilution of 0.5 mm RDT, cell changes were significantly different from control. Besides, no significant differences were found between the three experimental DBAs regarding cytotoxic effect on L929 cell line.

CONCLUSION

Considering the limitations of an in vitro study, if the RDT is less than 0.5 mm in vivo, regardless of the type of DBA, destructive cellular changes in pulp tissue can be expected.

Endodontic treatment of a taurodontism tooth: report of a case

Taurodontism is a rare dental anomaly in which the involved tooth has an enlarged and elongated body and pulp chamber with apical displacement of the pulpal floor. Endodontic treatment of these teeth is challenging, because it is hard to identify the number of root canals. In this article a case of bilateral involvement of maxillary first molars is presented. Endodontic treatment of right maxillary first molar with taurodontism was indicated due to irreversible pulpitis. This article describes the procedures of root canal therapy.

A Comparative Study on the Amount of Extruded Material from the Apical Foramen with NiTi Rotary and Stainless Steel Hand Instruments

INTRODUCTION

The purpose of the present study was to quantify and compare the amount of extruded debris from apical foramen after instrumentation of the root canal system with hand and rotary instruments.

MATERIALS AND METHODS

Root canals of forty five fresh extracted single rooted human teeth with mature apexes and less than 15 degree of root curvature were instrumented in group A with stainless steel K-Type files, in group B with rotary NiTi Flex Master files, and in group C with rotary NiTi ProTaper files and followed weighting the extruded debris by a digital scale to within 0.0001 gram accuracy.

RESULTS

In all groups, the mean weight of extruded debris was not more than 5 mg (P=0.0l) and was ranked as: Group A>Group B>Group C. There were statistically significant differences among three groups (p=0.0l). The mean value of extruded debris in the ProTaper and Flex Master groups were 0.652 and 0.788 mg, respectively.

CONCLUSION

The study revealed that the amount of extruded debris from the apical foramen was minimal when ProTaper files were used.

Bilateral open treatment of spontaneous pneumothorax: a new access

A new technique for bilateral apical bullectomy and pleurectomy via axillary minithoracotomy and transmediastinal access to the contralateral side, was used in 13 patients with bilateral apical blebs and/or pneumothorax. The contralateral space is reached at the posterior superior mediastinum, passing between the first thoracic vertebral bodies (T1-T4) and the oesophagus. The contralateral lung apex is then pulled into the thoracotomy side and apical bullectomy carried out by linear stapler. The obvious advantages of avoiding a second thoracotomy while providing complete solution to the clinical problem are particularly important in young patients with spontaneous pneumothorax caused by bilateral apical blebs.

Patterns of systolic stress distribution on mitral valve anterior leaflet chordal apparatus. A structural mechanical theoretical analysis

Increasing diffusion and complexity of mitral valve repair procedures may prompt an interest in the evaluation of the patterns of stress distribution on the chords, which are, from the structural mechanical point of view, the weakest element of valve apparatus. This theoretical analysis concentrates in particular on the mitral valve anterior leaflet. As is known, the vast majority of the chordae are attached to the anterior leaflet within the coaptation area; during systole they are then necessarily parallel, aligned along the same plane as that of the leaflets' coaptation surface, to which they are attached; moreover the thickness of the chordae increases significantly from the marginal chordae to the more central ones. In normal conditions during systole the progressively wider coaptation surface causes the increasing stress to be supported by an increasing number of progressively thicker chords, which are substantially parallel and aligned on the coaptation surface plane in such a way that they can share the stress between them, according to their thickness; in other words chords form a multifilament functional unit which enrolls elements of increasing thickness in response to the mounting stress. The geometrical modifications of the valve apparatus architecture (annulus dilatation, leaflet retraction, chordal elongation or retraction) often associated with valve insufficiency due to chordal rupture, have the common result of causing, during systole, a radial disarrangement of the direction of most of the secondary chordae which are no longer parallel, aligned on the coaptation surface plane. Due to the negligible elastic module of the valve leaflet, in this new arrangement the various chordae cannot share the stress between themselves as they do in a normal physiological situation; on the contrary the thinner chordae nearer to the free margin are also loaded with the peak systolic stress, thus generating conditions favoring their rupture. It can, therefore, be hypothesized that the anatomopathological picture of valve insufficiency due to chordal rupture may be the final event of a series of geometrical modifications of valve apparatus architecture, the common consequence of which is to load thinner marginal chords with peak systolic stress from which they are normally spared, thus favoring their rupture.

[Partial resection of the tracheal wall and introverting tracheoplasty]

A tracheal tumor involving roughly the half circumference of the tracheal wall and 3.5 cm length, was resected preserving the part of the tracheal cylinder not invaded by the tumor; reconstruction was carried out by an introverting tracheoplasty. This reconstruction technique, already successfully carried out in main bronchus resections, allowed iuxtapositioning of the tracheal rims very firmly without tension, the maneuvers for laryngeal or carenal release being not necessary.

Descending aorta substitution with expandable ends prosthesis. Case report

A case of esophageal cancer infiltrating the left bronchus pars membranacea and the aneurysmal aortic wall was resected en bloc with the bronchial and aortic wall. Descending aorta was substituted by means of a Dacron prosthesis fitted with expandable devices at both ends, allowing a very significant reduction of the clamping time and simplification of this part of the procedure.

[Longitudinal bronchotomy on the pars membranacea for endoscopic foreign body extraction]

Purpose of this paper is to report a case of foreign body obstructing the middle lobe bronchial origin, surgically removed through a longitudinal bronchotomy on the pars membranacea, reached by passing posteriorly to the lung. Anatomical considerations suggest that longitudinal bronchotomy on the pars membranacea of the main bronchial axis (stem bronchi, intermedius br (right), and lower lobar bronchus) gives direct visualization from inside also of foreign bodies sited into the lobar bronchi (sup, middle and lingula), allowing an easy bronchotomy repair, without lumen distortion or stenosis. Since the pulmonary artery is not in contact with this pars membranacea, broncho-arterial fistula in case of suture line dehiscence is quite improbable.

[The surgical physiopathology of essential pulmonary emphysema and volume-reduction intervention]

The breaking of the interalveolar septa represents, in the pathogenetic mechanism of emphysema, a final event, common to the different etiologic agents. This elementary injury causes a series of consequences, essentially of mechanic-structural type (intrapulmonary aerial spaces-confining parenchyma collapse, bronchial obstruction, dead space augmentation) on the thin and articulate bronchoalveolar architecture, whose final rearrangement determines, at least in part, the clinical picture. In short, the break of alveolar septa involves the formation of intraparenchymal aerial spaces with collapse of the confining lung; the compensatory mechanism to this situation, involves the hyperexpansion of the thoracic cage and flattening of the diaphragm, with the aim of allowing ventilation of the healthy residual parenchyma. Because of the finite capability of expansion of the thoracic cage and of the diaphragm in respect to the theoretical capability of the lung of large intraparenchymal aerial spaces formation, it is easy to imagine that emphysema can cause a serious functional respiratory deficit even before a significant quantity of pulmonary parenchyma is destroyed by the pathogenic process. It may then be hypothesized that a simple reduction of the volume of the lung, even sacrificing a part of "working" parenchyma, might allow the residual lung to come back to a normal ventilation, wholly ameliorating the respiratory exchanges. The clinically more remarkable consequence of lung volume reduction is the amelioration of ventilation mechanics with a decreased respiratory work due to the shift of the tidal volume toward values less proximal to the maximal expandability of the thoracic wall and of the diaphragm. On the other end, it is possible to anticipate an equally significant effect on bronchial obstruction, due to the more favorable matching of the compliance of the thoracic wall and that of the lung. LVRS has significant effect on the TV sharing ratio between emphysematous spaces and residual healthy parenchyma; the hyperexpansion of the residual lung in fact causes the distension of the emphysematous spaces, continuing in the natural compensatory mechanism of the emphysema. The decreased ventilation and thus re-breathing of the residual emphysematous spaces, together with the improved ventilation may ameliorate hypercapnia. Obviously no direct effects can be expected from LVRS on the conditions of the alveolar membrane and thus on gas diffusion capacity through it. The time duration of the amelioration achieved with the lung volume reduction is still to be demonstrated.

[Physiopathology of pulmonary emphysema. Analysis of structural changes in the pulmonary architecture and therapeutic implications]

In the pulmonary emphysema a serious respiratory inadequacy can result from the impossibility of the thoracic cage and of the diaphragm to expand beyond a maximum limit, before that a significnat part of pulmonary parenchyma has been destroyed by the pathogenic process. The resection of part of the lung, selectively in the areas where the emphysematous injuries are more pronounced, brings again the ventilation of the residual pulmonary parenchyma toward more physiological expansion values of the thoracic cage and diaphragm, thus decreasing the respiratory work, improving the ventilation mechanics and the bronchial obstruction. The time duration of the improvement achieved with the lung volume reduction is still to be demonstrated. A clinical and therapeutic analysis of this pathology is carried out.

Prosthesis for aortic arch substitution

BACKGROUND

The risk of neurologic complications in aortic arch prosthetic substitution is directly related to the duration of the circulatory arrest. The purpose of this article is to report the experiments on animals of a device for simplifying and quickening the vascular anastomosis in aortic arch substitution.

METHODS

The device consists of expandable loops of stainless steel wire, sewn to the proximal end of a Dacron prosthesis. An actuating removable guide allows the stainless steel wire loops to be expanded and tightened, in such a way that the prosthesis diameter is varied, while maintaining a regular cylindric shape. The prosthesis end is then transformed into a rigid cylindrical ring, approximately half the maximal diameter in length, with a variable and controllable diameter. A composite graft was prepared, fitted with the expandable device at the distal end of the main prosthesis as well as at each end of the branches for the supraaortic trunks. Cardiopulmonary bypass was established by cannulation of the right atrium and left iliac artery. The prosthesis was positioned very easily and quickly during a brief hypothermic circulatory arrest; ascending aorta anastomosis was carried out by the standard technique after central nervous system reperfusion was resumed. Acute experiments were carried out in 5 swine.

RESULTS

Four of 5 animals survived the procedure without detectable neurologic sequelae. At sacrifice the prosthesis was found to be properly sited without lumen distortion or thrombosis.

CONCLUSIONS

The main advantages of this device and modality of arch substitution in a clinical setting would include drastic reduction of the circulatory arrest time, easy and reliable hemostasis of the anastomosis line, and accurate and firm approximation of the dissection layers in case of dissecting aneurysms.

[A device for synthesis of the costal plane after posterolateral thoracotomy using transosseous incisions to prevent compression of intercostal nerves]

The purpose of this paper is to illustrate the use of a device to quickly perform little holes in the costal lateral arch for synthesis of the standard posterolateral thoracotomy. The working principle of the instrument is similar to that of a hollow punch device. Preliminary laboratory experience allowed to identify the best diameter of the costal holes (2 mm), without fracture. Absorbable suture were passed through the holes and tied to approximate the facing ribs. The modality of costal plane synthesis, very easy and quick with this device, makes possible to prevent intercostal nerve compression and accidental intercostal vessel lacerations. The so frequent, severe and often long lasting painful sequelae of thoracotomy, on the other hand so rare in other surgical wound (i.e. laparotomy, sternotomy, etc.) justify in our opinion the routine use of this costal plane synthesis technique.

[Invaginated bronchoplasty: wedge resection and sleeve reconstruction]

The purpose of this report is to illustrate a bronchoplastic technique in upper right lobectomy which is equivalent to sleeve resection but allows to preserve the unaffected portion of the bronchial wall. The technique consists in the resection of the infiltrated bronchial wall, sparing the unaffected part The distal bronchial stump is then invaginated into the stem bronchus in such a way that the anastomosis line is located at the highest possible level, ideally where it would be carried out if standard sleeve resection would be performed. The anastomosis is accomplished by U-Shaped, 3-0 vicryl sutures. The major advantage of this procedure is probably due to the preservation of the systemic artery bronchial supply to the distal stump passing through the unaffected bronchial wall; the resulting more vital distal stump may reduce incidence of suture line healing problems.

Potentials of liposomes in diagnosis and treatment of pulmonary metastases: an experimental study in the rat

OBJECTIVE

The ultimate goal of the therapy of lung metastases is to destroy all malignant cells while sparing normal ones. Liposomes represent a novel approach for the selective transport of tracers and therapeutic agents to cancer cells because of their flexibility, low toxicity, wide range of possible variants, simplicity to make, and because agents can be entrapped in them in their native states in large amounts. We have studied the biodistribution of "Stealth" liposomes in the experimental model of lung metastases in the rat.

METHODS

The secondaries were induced by i.v. injection 20. 10(6) cancer cells (DHD/K12/TRb line) in BD-IX rats. The study of the liposome biodistribution in the rat was carried out by the use of unilamellar liposomes with homogeneous size distribution (0.1 microns), the liposomes were labeled with Cholesteryl-Bodipy. The rats were sacrificed at scheduled times after the injection; blood, urine, metastatic and healthy lung, colon, liver and spleen were analysed by a microcytofluorimetric examination.

RESULTS

Liposomes prolonged the circulation time of Cholesteryl-Bodipy. Only spleen and lung metastases exhibited an accretion of fluorescent liposomes.

CONCLUSIONS

The biodistribution of such formulation of liposomes in rats with lung metastases, may be of considerable importance in diagnosis and therapy of the secondaries, for increasing the concentration of tracers and therapeutic agents in tumor tissue while minimizing the likelihood of aspecific distribution and toxicity to non target tissue.