Odontogenic tumours in a Chilean population: a retrospective study of 544 cases based on 2022 WHO classification

BACKGROUND

Odontogenic tumours are infrequent lesions. Studies on the frequency of odontogenic tumours from Latin America are scarce. This work aimed to determine the relative frequency of odontogenic tumours in a Chilean population using the 2022 World Health Organization classification.

MATERIAL AND METHODS

This is a case series retrospective study. We reviewed 35,530 samples from 1975 to 2022 from the Oral Pathology Referral Institute and the Pathological Anatomy Service, Faculty of Dentistry, University of Chile. We utilized the 2022 World Health Organization classification for histological typification.

RESULTS

According to 2022 World Health Organization classification, 544 odontogenic tumours were confirmed. The most frequent odontogenic tumours were: odontoma (n=241; 44.3%), ameloblastoma (n=109; 20.0%) and cemento-ossifying fibroma (n=71; 13.1%). Benign odontogenic tumours corresponded to 538 cases (98.9%) and malignant tumours were only six cases (1.1%).

CONCLUSIONS

In our population, odontoma was the most frequent odontogenic tumour followed by ameloblastoma and cemento-ossifying fibroma. Malignant odontogenic tumours were very rare. The results of this study are similar to reports from America, but there are some differences concerning the data from Africa and Asia.

Supplementary Table 1D from Allelic Transcripts Dosage Effect in Morphologically Normal Ovarian Cells from Heterozygous Carriers of a <i>BRCA1</i>/<i>2</i> French Canadian Founder Mutation.. [DOI: 10.1158/1940-6207.22523569.v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

<p>PDF file - 177K, Molecular signature associated to the tumor transformation from NOSEs to TOVs in BRCA1-mutated samples</p>

Supplementary Table 1C from Allelic Transcripts Dosage Effect in Morphologically Normal Ovarian Cells from Heterozygous Carriers of a <i>BRCA1</i>/<i>2</i> French Canadian Founder Mutation.. [DOI: 10.1158/1940-6207.22523572.v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

<p>PDF file - 95K, Molecular profile differentiating BRCA1- from BRCA2-mutated NOSEs</p>

Supplementary Table 1A-B from Allelic Transcripts Dosage Effect in Morphologically Normal Ovarian Cells from Heterozygous Carriers of a <i>BRCA1</i>/<i>2</i> French Canadian Founder Mutation.. [DOI: 10.1158/1940-6207.22523575.v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

<p>PDF file - 92K, Supplementary Table 1a. Molecular profile associated to a BRCA1 mutation in NOSEs Supplementary Table 1b. Molecular profile associated to a BRCA2 mutation in NOSEs</p>

Supplementary Table 3 from Allelic Transcripts Dosage Effect in Morphologically Normal Ovarian Cells from Heterozygous Carriers of a <i>BRCA1</i>/<i>2</i> French Canadian Founder Mutation.. [DOI: 10.1158/1940-6207.22523563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

<p>PDF file - 99K, Common genes between our results and published inherited ovarian literature</p>

Supplementary Table 1A-B from Allelic Transcripts Dosage Effect in Morphologically Normal Ovarian Cells from Heterozygous Carriers of a <i>BRCA1</i>/<i>2</i> French Canadian Founder Mutation.. [DOI: 10.1158/1940-6207.22523575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

<p>PDF file - 92K, Supplementary Table 1a. Molecular profile associated to a BRCA1 mutation in NOSEs Supplementary Table 1b. Molecular profile associated to a BRCA2 mutation in NOSEs</p>

Cambridge hybrid closed-loop algorithm in children and adolescents with type 1 diabetes: a multicentre 6-month randomised controlled trial

BACKGROUND

Closed-loop insulin delivery systems have the potential to address suboptimal glucose control in children and adolescents with type 1 diabetes. We compared safety and efficacy of the Cambridge hybrid closed-loop algorithm with usual care over 6 months in this population.

METHODS

In a multicentre, multinational, parallel randomised controlled trial, participants aged 6-18 years using insulin pump therapy were recruited at seven UK and five US paediatric diabetes centres. Key inclusion criteria were diagnosis of type 1 diabetes for at least 12 months, insulin pump therapy for at least 3 months, and screening HbA1c levels between 53 and 86 mmol/mol (7·0-10·0%). Using block randomisation and central randomisation software, we randomly assigned participants to either closed-loop insulin delivery (closed-loop group) or to usual care with insulin pump therapy (control group) for 6 months. Randomisation was stratified at each centre by local baseline HbA1c. The Cambridge closed-loop algorithm running on a smartphone was used with either (1) a modified Medtronic 640G pump, Medtronic Guardian 3 sensor, and Medtronic prototype phone enclosure (FlorenceM configuration), or (2) a Sooil Dana RS pump and Dexcom G6 sensor (CamAPS FX configuration). The primary endpoint was change in HbA1c at 6 months combining data from both configurations. The primary analysis was done in all randomised patients (intention to treat). Trial registration ClinicalTrials.gov, NCT02925299.

FINDINGS

Of 147 people initially screened, 133 participants (mean age 13·0 years [SD 2·8]; 57% female, 43% male) were randomly assigned to either the closed-loop group (n=65) or the control group (n=68). Mean baseline HbA1c was 8·2% (SD 0·7) in the closed-loop group and 8·3% (0·7) in the control group. At 6 months, HbA1c was lower in the closed-loop group than in the control group (between-group difference -3·5 mmol/mol (95% CI -6·5 to -0·5 [-0·32 percentage points, -0·59 to -0·04]; p=0·023). Closed-loop usage was low with FlorenceM due to failing phone enclosures (median 40% [IQR 26-53]), but consistently high with CamAPS FX (93% [88-96]), impacting efficacy. A total of 155 adverse events occurred after randomisation (67 in the closed-loop group, 88 in the control group), including seven severe hypoglycaemia events (four in the closed-loop group, three in the control group), two diabetic ketoacidosis events (both in the closed-loop group), and two non-treatment-related serious adverse events. There were 23 reportable hyperglycaemia events (11 in the closed-loop group, 12 in the control group), which did not meet criteria for diabetic ketoacidosis.

INTERPRETATION

The Cambridge hybrid closed-loop algorithm had an acceptable safety profile, and improved glycaemic control in children and adolescents with type 1 diabetes. To ensure optimal efficacy of the closed-loop system, usage needs to be consistently high, as demonstrated with CamAPS FX.

FUNDING

National Institute of Diabetes and Digestive and Kidney Diseases.

Associated factors of patients with spinal stenosis who undergo reoperation after a posterior lumbar spinal fusion in a Hispanic-American population

PURPOSE

The aim of this study was to evaluate the associated factors of patients with LSS who undergo reoperation after a PLSF in a Hispanic-American population.

METHODS

A retrospective single-center review was performed from all non-age-related Hispanic-Americans with LSS who underwent one or two-level PLSF from 2008 to 2018. Baseline characteristics were analyzed between the reoperation and no-reoperation group using a bivariate and multivariate analyses.

RESULTS

Out of 425 patients who underwent PLSF, 38 patients underwent reoperation. At a two-year follow-up, the reoperation rate was 6.1% (26/425), mostly due to pseudoarthrosis (39.5%), recurrent stenosis (26.3%), new condition (15.8%), infection (10.5%), hematoma (5.3%), and dural tear (2.6%). Patients who underwent reoperation were more likely to have a preoperative history of epidural steroid injection (ESI) (OR 5.18, P = 0.009), four or more comorbidities (OR 2.69, P = 0.028), and operated only with a posterolateral fusion without intervertebral fusion (OR 2.15, P = 0.032). Finally, the multivariable analysis showed that ESI was the only independent associated factor in patients who underwent reoperation after a PLSF in our group.

CONCLUSION

Among this population who underwent surgery, a reoperation rate at two years of follow-up was less than ten percent. Our study did not find any associated factor inherent to Hispanic-Americans, as ethnic group, who were reoperated after LSS.

Maximum artificial intelligence and complete reconstruct of population-based AMI care

Background

After creating a behemoth hub and spoke AMI network that encompasses more than 100 million patients in 5 countries, we have begun to incorporate Artificial Intelligence (AI) algorithms into our telemedicine strategy with the goal of creating comprehensive, very early AMI diagnosis and physician-free triage. In doing so, we have replaced door-to-balloon times (d2b) with symptom-to-balloon times (s2b) as an immutable objective.

Purpose

To incorporate AI attributes for very early AMI detection, triage, and management.

Methods

We expanded our effective telemedicine strategy (100 million population; 877,178 telemedicine encounters; 55% overall mortality reduction; $291 million cost savings) with a logistic reset to impact s2b. To do this, we incorporated our Single Lead 1.0 (lead I) and Single Lead 2.0 (lead V2) technology for self-administered AMI detection with our physician-free STEMI diagnosis and triage AI algorithms. Single Lead algorithms and physician-free protocols were generated by utilizing Machine Learning from our mammoth annotated EKG repository.

Results

In addition to three logistic markers of efficiency Time-to-Telemedicine Diagnosis (TTD), Door-In-Door-Out (DIDO) and Transfer Times (TT); we are monitoring s2b. A gradual release of the algorithms and single lead is occurring at the telemedicine spokes. Detailed results will be available at the time of presentation.

Conclusions

Impacting s2b, the Achilles Heel of Primary PCI, may be achieved with the use of patient-administered AMI detection tools. Incorporation of these technologies into AI algorithms will add to telemedicine efficiencies for population-based AMI care.

Funding Acknowledgement

Type of funding source: None

AI and telemedicine: total remote guidance of AMI management

Background

For a decade, Latin American Telemedicine Infarct Network (LATIN) Telemedicine has transformed AMI management in Brazil, Colombia, Mexico, Chile, and Argentina. With a hub and spoke strategy, AMI coverage was expanded to 100 million population and 877,177 telemedicine encounters were performed. Cost savings from avoiding unnecessary transfer of patients was $291 million. We are now rapidly escalating on a path to making the telemedicine process “physician-free” by utilizing Artificial Intelligence (AI) protocols.

Purpose

To demonstrate that AI can replace a cardiologist for remote AMI telemedicine guidance.

Methods

The process of total AI guidance focused on both aspects of our telemedicine strategy – accurate AMI diagnosis and tele-guidance of the entire STEMI process. We developed our innovative approach by initially creating AI algorithms for computer-aided diagnosis. Next, we incorporated logistic variables (duration of chest pain, transfer times to LATIN hub, etc) to the algorithm for physician-free triage into thrombolysis, primary PCI and pharmaco-invasive management. The intent of creating AI algorithms was early STEMI detection and triage. After the patient was efficiently transferred to the hub, a final treatment decision was made by the hub cardiologists.

Results

Three crucial areas of telemedicine efficiency are being monitored – Time-to-Telemedicine Diagnosis (TTD), Door-In-Door-Out (DIDO) and Transfer Times (TT). All are showing improvements. Detailed results will be available at the time of presentation.

Conclusions

We are encouraged with the possibility of making the entire telemedicine guidance of AMI management “physician-free”. Next-Gen improvements are being contemplated by including a Single Lead EKG for AMI detection that will impact symptom-to-balloon times.

Funding Acknowledgement

Type of funding source: None

Moving in sync – concordance betweena artificial intelligence and cardiologist on detecting normal electrocardiograms

Background

Merging modern technologies with classic diagnostic tests often results in a sense of insecurity within the medical community, particularly so with potentially life-saving studies such as the electrocardiogram (EKG). In order to provide a greater sense of trust between Artificial Intelligence (AI) and cardiologists, we provide an AI-driven algorithm capable of accurately and reliably characterize an EKG as normal within a highly complex, cardiologist-reviewed EKG database and report the degree of concordance between this machine vs physician scenario.

Purpose

To provide a dependable and accurate AI algorithm that conducts EKG interpretation in a cardiologist-tier manner.

Methods

The International Telemedical System (ITMS) developed and tested an EKG assessing AI algorithm and incorporated it into the workflow of their Telemedicine Integrated Platform, a digital EKG reading program where cardiologists continuously report their findings remotely in real-time. During the month of April 2,019; 35 ITMS cardiologists reported a grand total of 61,441 EKG records, later submitting them to the AI algorithm implemented through the “One Click Report” process. Through this simple 2-step approach, the algorithm provides a suggestion of “Normal” or “Abnormal” to the cardiologist based on the patterns of the fiducial points included in said EKG reports. Confirmation of these suggestions by the cardiologists ensued.

Results

Overall, cardiologists confirmed 23,213 out of 25,013 AI outputs for “Normal” EKGs, demonstrating a concordance of 92.8% for Normal diagnosis.

Conclusion

Through this methodology, we provide an AI technology that can be reliably applied and trusted in EKG digital platforms to identify and suitably label a normal EKG. Further testing will accrue into a multi label algorithm compatible with abnormal cardiovascular entities, potentially precluding the role of the cardiologist for triaging, particularly in the prehospital setting. We anticipate that this approach will become a promising methodology in modern cardiology practice.

Funding Acknowledgement

Type of funding source: None

Enriching artificial intelligence ST-elevation myocardial infarction (STEMI) detection algorithms with differential diagnoses

Background

STEMI outcomes, although improved with systems of care, are hamstrung by delayed presentation and prevaricates of a 12-lead ECG. We report an artificial intelligence (AI) guided, single lead EKG algorithm for a self-administered tool to reliably detect STEMI and trigger ambulance dispatch.

Purpose

To provide a reliable and improved AI-guided Single Lead EKG methodology.

Methods

From our cardiologist-annotated repository, we assigned a dataset of 11,118 classified ECG. Ontology organized 5 groups apportioned for an interclass balance among commoner STEMI differential diagnoses. This anonymous, pre-classified data included 5,549 STEMI, 1,391 normal, 1,393 Bundle Branch Block, 1,393 non-specific ST-T changes and 1,392 miscellaneous. Each ECG was fragmented into individual 1-lead strips. Algorithm: 1-D Convolutional Neural Networks. Gender and age were included before the last dense layer. Training and Testing: Preset 90% dataset (10,008 ECG) train, 10% test (1,110 ECG). Statistical Analysis and ROC curves: Digitized dataset, 500 samples/second, 10s duration, total 5,000 samples per lead. Statistical mean for each lead was calculated and subtracted from the original lead. Statistical values and ROC curves were assessed.

Results

Most Accurate: Lead V2 – 91%; Most Sensitive: Lead I – 92% Most Specific: Lead III – 96%. Best AUC: Lead V2 – 91%.

Conclusions

Incorporating subtypes of STEMI differential diagnosis enriches the single lead AI algorithm. Validating the derived algorithm with our entire database of 18 million ECG will further strengthen the results.

Funding Acknowledgement

Type of funding source: None

Effect of sphingosine-1-phosphate on cryopreserved sheep testicular explants cultured in vitro

Complete spermatogenesis has been achieved in vitro in mouse testicular explants with resulting sperm used to produce pups after Intra Cytoplasm Sperm Injection and Embryo Transfer. In the present study, we evaluated the influence of sphingosine-1-phosphate (S1P) on spermatogenesis of frozen-thawed lamb testis explants in vitro. Thawed testicular pieces were cultured for 12 d on agarose blocks in serum-free growth medium containing 0, 2, 5 or 10 μM S1P. At the end of D6 and D12, some pieces were fixed and processed for histology. Other pieces were processed for RNA isolation and quantitation of proliferation (PCNA, Ki67) and differentiation (PLZF) markers and genes involved in S1P signaling (S1PR1, SGPL1, SGPP1, AKT1 and NFKBIA) by qPCR. Histology revealed an increase (P < 0.05) in seminiferous cord (SC) diameter under all culture conditions, except 5 and 10 μM S1P by D6. In the presence of 5 μM S1P, percentage of gonocytes decreased (P < 0.05) by D6 (control, 24.9% vs. S1P, 10.3%) with a concomitant increase (P < 0.05) in spermatogonia formation (control, 74.4% vs. S1P, 88.1%). S1P induced PCNA or Ki67 expression by D6, whereas PLZF was up-regulated (P < 0.05) by D6 in 2 μM S1P and D12 in 5 & 10 μM S1P. Expression of SGPL1 and SGPP1 increased 4-12-fold in tissues cultured in 10 μM S1P by D12 compared to D12 control. AKT1 and NFKBIA mRNA expression was low (P < 0.05) in 5 and or 10 μM S1P treatments on D6. These results demonstrate that S1P promotes germ cell proliferation during first week of culture and may exert an anti-apoptotic influence on the seminiferous cord in sheep testicular explants in vitro.

Estudio bioquímico del veneno de la anémona de mar Phymactis papillosa (Actiniidae)

En este trabajo se ha estudiado bioquímicamente el veneno de Phymactis papillosa, colectadas en la bahía de Ancón. El veneno fue obtenido mediante shock hipotónico y luego se liofilizó. El análisis electroforético del veneno soluble mostró la presencia de 5 bandas proteicas con pesos moleculares entre 5 y 25.1 kDa.El veneno soluble fue fraccionado por cromatografía de filtración en una columna de Sephadex G-50, obteniéndose cuatro picos de proteína (I, II, III y IV). Tanto en el veneno soluble como en las fracciones colectadas se midió actividad de proteasa, fosfolipasa, hialuronidasa, fosfatasa ácida y fosfatasa alcalina; así como, actividad hemolítica y neurotóxica. Se encontró actividad proteolítica sobre caseína, en el veneno soluble y en los picos I y III. No se detectó actividad de fosfolipasa, hialuronidasa, fosfatasa ácida y fosfatasa alcalina. La actividad hemolítica, ensayada sobre eritrocitos humanos, se encontró en el veneno soluble y en el pico II. Finalmente, tanto el veneno soluble como el pico III mostraron ser neurotóxicos al ser inyectados en ratones albinos vía intraperitoneal. Se concluye que el veneno soluble de P. papillosa tiene actividad proteolítica, hemolítica y neurotóxica.

Oxidation of free, peptide and protein tryptophan residues mediated by AAPH-derived free radicals: role of alkoxyl and peroxyl radicals

When AAPH is employed as a free radical source, at low concentrations of free, peptide and protein Trp residues, the oxidation is mostly induced by alkoxyl radicals. However, at high concentrations, both peroxyl and alkoxyl radicals are involved.

Anethole improves the in vitro development of isolated caprine secondary follicles

The aim of this study was to investigate the effect of three concentrations of anethole (30, 300, and 2000 μg/mL) on survival, antrum formation, follicular diameter, and oocyte maturation in the caprine species. The study also evaluated the effects of anethole on transcripts of ICAM-1, CAV-1, TIMP-2, and PAI-1 genes and levels of reactive oxygen species (ROS) in isolated goat preantral ovarian follicles before and after in vitro culture for 18 days. Preantral follicles were isolated from goat ovaries and individually cultured in alpha minimum essential medium modified (α-MEM⁺), defined as the control treatment, α-MEM⁺ supplemented with ascorbic acid at a concentration of 100 μg/mL (AA), or α-MEM⁺ supplemented with three different concentrations of anethole (30, 300, 2000 μg/mL) for a period of 18 days. Treatments were named as α-MEM⁺, AA, AN30, AN300, and AN2000, respectively. After culture, the follicles were opened, the cumulus oocytes complex (COCs) were removed and matured in vitro. The walls of the follicles were used for the quantitation of mRNA by quantitative real-time polymerase chain reaction. Finally, the medium collected at the end of culture was used for the measurements of ROS. After 18 days of culture, the AA treatment showed the percentage of intact follicles and follicular diameter significantly higher compared with the other treatments. However, daily growth rate, antrum formation, and also oocyte diameter were similar among the treatments. In addition, compared with AA, the rate of oocytes for in vitro maturation (diameter ≥ 110 μm) and the meiosis resumption rate were significantly higher in the treatments AN30 and AN2000, respectively. When assessing gene related to remodeling of the basement membrane, significant differences in mRNA levels for ICAM-1, CAV-1, TIMP-2, and PAI-1 were observed in comparison with Day 0, i.e., in the noncultured control. In addition, the ROS from Day 12, all treatments with the addition of anethole have significantly lower values of ROS than α-MEM⁺ and AA. In conclusion, the addition of anethole to the in vitro culture medium was able to improve the development of goat preantral follicles by reducing concentrations of ROS and increasing the percentage of oocytes able to resume meiosis.

Allelic transcripts dosage effect in morphologically normal ovarian cells from heterozygous carriers of a BRCA1/2 French Canadian founder mutation

We hypothesized that the transcriptome of primary cultures of morphologically normal ovarian surface epithelial cells could be altered by the presence of a heterozygous BRCA1 or BRCA2 mutation. We aimed to discover early events associated with ovarian carcinogenesis, which could represent putative targets for preventive strategies of this silent killer tumor. We identified the first molecular signature associated with French Canadian BRCA1 or BRCA2 founder mutations in morphologically normal ovarian epithelial cells. We discovered that wild-type and mutated BRCA2 allelic transcripts were expressed not only in morphologically normal but also in tumor cells from BRCA2-8765delAG carriers. Further analysis of morphologically normal ovarian and tumor cells from BRCA1-4446C>T carriers lead to the same observation. Our data support the idea that one single hit in BRCA1 or BRCA2 is sufficient to alter the transcriptome of phenotypically normal ovarian epithelial cells. The highest level of BRCA2-mutated allele transcript expression was measured in cells originating from the most aggressive ovarian tumor. The penetrance of the mutation and the aggressiveness of the related tumor could depend on a dosage effect of the mutated allele transcript.

A rare case of paraplegia complicating a lumbar epidural infiltration

OBJECTIVE

We report the case of a patient who developed paraplegia following a low lumbar epidural steroid injection. Alternative approaches to (or alternative means of) performing transforaminal injections should be considered, in order to avoid devastating neurological complications.

CASE REPORT

A 54-year-old man (who had undergone surgery 14 years earlier to cure an L5-S1 slipped disc with right S1 radiculopathy) presented with low back pain (which had begun 6 weeks previously) and left S1 radiculopathy. During a second infiltration of prednisolone acetate, the patient reported feeling a heat sensation in his legs and concomitantly developed facial flushing. Immediately after the injection, the patient developed complete, flaccid T7 ASIA A motor and sensory paraplegia. Three days later, T2 magnetic resonance imaging (MRI) of the spine revealed a spontaneous hypersignal in the conus medullaris and from T6 to T9, suggesting medullary ischemia. Recovery has been slow; after 4 months of treatment in a physical and rehabilitation medicine department, urinary and sensory disorders are still present (T7 ASIA D paraplegia). The patient can walk 200 m unaided. Three months later, the MRI data had not changed.

DISCUSSION

This is a rare case report of paraplegia following low lumbar epidural infiltration via an interlaminar route. The mechanism is not clear. Most of authors suggest that the pathophysiological basis of this type of complication is ischemia caused by accidental interruption of the medullary blood supply. Direct damage to a medullary artery, arterial spasm or corticosteroid-induced occlusion due to undetected intra-arterial injection could result in medullary infarction. This serious incident should prompt us to consider how to avoid further problems in the future. It also raises the issue of providing patients with information on the risks inherent in this type of procedure.

CONCLUSION

Despite the rarity of this complication, patients should be made aware of its potential occurrence. In the case reported here, the functional prognosis is uncertain.

Blockage of angiotensin II type I receptor decreases the synthesis of growth factors and induces apoptosis in C6 cultured cells and C6 rat glioma

Angiotensin II (Ang II) is a main effector peptide in the renin–angiotensin system and participates in the regulation of vascular tone. It also has a role in the expression of growth factors that induce neovascularisation which is closely associated to the growth of malignant gliomas. We have shown that the selective blockage of the AT₁ receptor of angiotensin inhibites tumour growth, cell proliferation and angiogenesis of C6 rat glioma. The aim of this study was to study the effects of the blockage of AT₁ receptor on the synthesis of growth factors, and in the genesis of apoptosis in cultured C6 glioma cells and in rats with C6 glioma. Administration of losartan at doses of 40 or 80 mg kg⁻¹ to rats with C6 glioma significantly decreased tumoral volume and production of platelet-derived growth factor, vascular endothelial growth factor and basic fibroblast growth factor. It also induced apoptosis in a dose-dependent manner. Administration of Ang II increased cell proliferation of cultured C6 cells which decreased by the administration of losartan. Our results suggest that the selective blockage of AT₁ diminishes tumoral growth through inhibition of growth factors and promotion of apoptosis.

[Isaac and Jose Horwitz in Chilean psychiatry]

During the XXth century, neuropsychiatrists Isaac and José Horwitz worked in the Asylum, the current Psychiatric Institute Dr José Horwitz. While Isaac dedicated part of his time to teach in Medical and Nursing Schools, his brother José preferred clinical work on mental health. Both chaired consecutively the Service A of the old Hospital and José occupied in his last year the Director's position. After a scholarship in Mental Health in Baltimore, José developed, in conjunction with other outstanding colleagues, the first investigations on psychiatric morbidity in Chile, promoted the use of work therapy for individuals with chronic mental diseases, and helped to improve and plan projects for the prevention and treatment of alcoholism.

Asphalt volcanism and chemosynthetic life in the Campeche Knolls, Gulf of Mexico

In the Campeche Knolls, in the southern Gulf of Mexico, lava-like flows of solidified asphalt cover more than 1 square kilometer of the rim of a dissected salt dome at a depth of 3000 meters below sea level. Chemosynthetic tubeworms and bivalves colonize the sea floor near the asphalt, which chilled and contracted after discharge. The site also includes oil seeps, gas hydrate deposits, locally anoxic sediments, and slabs of authigenic carbonate. Asphalt volcanism creates a habitat for chemosynthetic life that may be widespread at great depth in the Gulf of Mexico.

Video-assisted versus open anterior lumbar spine fusion surgery: a comparison of four techniques and complications in 135 patients

STUDY DESIGN

A retrospective review involved 135 patients undergoing anterior interbody fusion using four different approaches: transperitoneal video-assisted surgery with insufflation, retroperitoneal endoscopic video-assisted surgery, minilaparotomy retroperitoneal surgery, and traditional oblique muscle-splinting retroperitoneal surgery.

OBJECTIVE

To describe and compare the operative procedure and perioperative complications of four different interbody fusion techniques.

SUMMARY OF BACKGROUND DATA

Although anterior lumbar interbody fusion surgery has a long history, several new and innovative approaches have been introduced recently. In contrast to the traditional oblique muscle-splitting retroperitoneal flank incision, the following have been used: a "minilaparotomy" open extraperitoneal approach through a small midline incision, a transperitoneal video-assisted insufflation technique, and a video-assisted gasless retroperitoneal endoscopic technique.

METHODS

A retrospective review was performed using the hospital records, operating room records, and clinic charts of 135 consecutive patients (50 men and 85 women) who underwent surgery between December 1993 and February 1998. Cases were included if either bone grafts alone or cylindrical cages with bone graft inside were used. Cases with anterior instrumentation using plates or rods were excluded. Diagnoses included degenerative disc disease, spondylolisthesis, or pseudarthrosis of a previous lumbosacral fusion. Patients with tumors or infection were excluded. The patients all were adults ranging in age from 17 to 83 years. Among the 135 patients, 12 had undergone previous anterior spine fusion surgery and 64 had undergone prior abdominal surgery.

RESULTS

The onset of new radicular pain or numbness, not experienced by the patient before surgery, occurred in six patients (18%; all with transperitoneal video-assisted surgery using insufflation). Vascular problems occurred in five patients (3.7% overall): two in the transperitoneal video-assisted group (5.9% of the group) and three in the minilaparotomy group (8.7% of the group). Retrograde ejaculation occurred in 4 of the 50 male patients (8% of the group): three in the transperitoneal video-assisted group (25% of the group) and one in the minilaparotomy group (2% of the group). Two patients had ureteral injuries (1.5% overall): one each in the retroperitoneal endoscopic and minilaparotomy groups. Conversion to open procedures was performed in seven patients (11% of the video-assisted procedures). The reasons for conversion included two major vessel lacerations and five peritoneal tears in the retroperitoneal video-assisted group.

CONCLUSIONS

A comparative analysis of four techniques for approaching the lower lumbar spine to perform arthrodesis in 135 patients showed an incidence of complications consistent with the literature for video-assisted techniques, but higher than for open techniques. For these and other reasons, the video-assisted approaches have been abandoned by the surgeons of this report.

[Arturo Vivado Orsini and the renewal of psychiatric treatments]

During the first half of the twentieth century, new psychiatric treatments were discovered, such as malario therapy, insulin therapy, electroshock, penicillin therapy, and the anti-alcoholic aversive therapy. These treatments gave a new hope to mental patients, even in our country. It was precisely while Dr. Arturo Vivado, Full Professor of Psychiatry at the University of Chile, worked and taught, that these treatments were progressively applied in Chile. After an effortful career, Dr. Vivado was appointed Director of the Psychiatric Asylum in Santiago, in 1945. He was a skillful clinician and pragmatic with his psychological belief, equanimus and affectionate with people. His most important contributions to the specialty are described in this review.

Hypertension and coronary heart disease

The association of hypertension and coronary heart disease is a frequent one. There are several pathophysiologic mechanisms which link both diseases. Hypertension induces endothelial dysfunction, exacerbates the atherosclerotic process and it contributes to make the atherosclerotic plaque more unstable. Left ventricular hypertrophy, which is the usual complication of hypertension, promotes a decrease of 'coronary reserve' and increases myocardial oxygen demand, both mechanisms contributing to myocardial ischaemia. From a clinical point of view hypertensive patients should have a complete evaluation of risk factors for atherosclerosis, damage of arterial territories other than the coronary one, and of the extension and severity of coronary artery involvement. It is important to emphasise that complications and mortality of patients suffering a myocardial infarction are greater in hypertensive patients. Treatment should be aimed to achieve optimal values of blood pressure, and all the strategies to treat coronary heart disease should be considered on an individual basis.

Proteolytic processing of the Cyt1Ab1 toxin produced by Bacillus thuringiensis subsp. medellin

Bacillus thuringiensis produces d-endotoxins that require proteolytic processing to become active. The activation of the B. thuringiensis subsp. medellin 28 kDa (Cyt1Ab1) cytolytic toxin by trypsin, chymotrypsin and gut extract from Culex quinquefasciatus larvae was analyzed. The Cyt1Ab1 toxin of B. thuringiensis subsp. medellin was processed by all proteases tested to fragments between 23 and 25 kDa, while processing of the Cyt1Aa1 toxin produce fragments between 22.5 and 24.5 kDa. The Cyt1Ab1 toxin was preferentially processed at the alkaline pH of 12. The in vitro proteolytic processing of the Cyt1Ab1 toxin by C. quinquefasciatus larvae midgut extract showed a 25 kDa fragment; a similar result was observed when the activation was performed in the in vivo experiments. The solubilized Cyt1Ab1 toxin and the protease resistant cores generated by in vitro processing showed hemolytic activity but not mosquitocidal activity. Amino terminal sequence of the C. quinquefasciatus gut extract resistant fragment indicated that the cutting site was located between Lys31 and Asp32, with a sequence DDPNEKNNHNS; while for the trypsin-resistant fragment the cutting site was determined between Leu29 and Arg30, and for the chymotrypsin-resistant fragment between Arg30 and Lys31.

[The Beca's in Chilean psychiatry]

The Chilean psychiatrists, Manuel and Francisco Beca, father and son, who lived at the turn of the XIX century and in the first half of the XX respectively, dedicated their lives to the care of mental patients and to the teaching of psychiatry, contributing in their own way and time to the development of the specialty in Chile. Manuel Beca, a clinician, published the first mental patient statistics and Francisco, an academic, became professor of Psychiatry at the Catholic University. Although they dedicated themselves to different fields in the area of mental health, such as clinical research and teaching, both have outstanding merits to become a part of the historical memory of Chilean psychiatry.

[Prevention of cardiovascular diseases: should the same criteria be applied in Latin America and Europe and North America?]

The prevention of cardiovascular diseases is based on the management of known cardiovascular risk factors by pharmacological means or by modifying lifestyles. A reduction in cholesterol levels is associated with a lower incidence of cardiovascular events and mortality, in both primary or secondary prevention trials. A reduction in blood pressure also leads to a decrease in acute myocardial infarction and the incidence of stroke. Regular exercise is associated with better disease free survival and the effects of smoking cessation are well known. High homocysteine levels are also associated with cardiovascular disease. However, there are no prospective clinical trials showing a beneficial effect of homocysteine reduction on cardiovascular mortality. A change in the type of dietary fat should also be beneficial, but this has not been proven in prospective clinical trials. In Chile, cardiovascular diseases are the leading cause of death among adults and the prevalence of cardiovascular risk factors, including hyperhomocysteinemia is similar to that of European or North American populations. Successful primary and secondary prevention programs to manage these risk factors have been developed in Chile. Therefore, the criteria applied in North America and Europe for the prevention of cardiovascular diseases, should be applied with slight modifications, in Latin American Countries.

Heart rate variability in severe aortic stenosis

BACKGROUND AND AIM OF THE STUDY

Autonomic dysfunction may be a risk factor for the generation of arrhythmias and sudden death in patients with severe aortic stenosis; thus, patients with this condition were studied to assess cardiac autonomic function.

METHODS

Twelve patients (five males, seven females; mean age 63 +/- 13 years) with severe symptomatic aortic stenosis before and after aortic valve replacement, were compared with a control group matched by age and sex. In the study group, mean fractional shortening was 36.5 +/- 5% and maximal aortic gradient 94.7 +/- 12 mmHg, assessed echocardiographically. Autonomic dysfunction was evaluated by following heart rate variability in both time and frequency domains. Spectral analysis was assessed at very low frequency (VLF: 0.017-0.05 Hz), low frequency (LF: 0.05-0.15 Hz) and high frequency (HF: 0.15-0.50 Hz). Heart rate variability was analyzed during three intervals, between 6:00-8:00 am (morning), 14:00-16:00 (afternoon) and 02:00-04:00 (night), and re-evaluated at 8-10 months after aortic valve replacement.

RESULTS

Compared with controls, patients with aortic stenosis presented a significantly lower heart rate variability in the morning and afternoon, analyzed either by time or frequency domain: 50 +/- 22 versus 132 +/- 52 ms (p < 0.05); VLF 5.0 +/- 1.5 versus 7.9 +/- 1.4 ln (ms)2 (p < 0.05); LF 4.9 +/- 1.7 versus 7.5 +/- 1.8 ln (ms)2 (p < 0.05); HF 5.3 +/- 1.4 versus 7.5 +/- 1.8 ln (ms)2 (p < 0.05). Results at night showed a similar tendency, but were not statistically significantly different. At 8-10 months after aortic valve replacement, heart rate variability was increased significantly during the morning, from 50 +/- 22 to 79.5 +/- 22 ms (p < 0.05); VLF from 5.0 +/- 1.5 to 6.7 +/- 0.8 ln (ms)2 (p < 0.05); LF from 4.9 +/- 1.7 to 6.2 +/- 1.3 ln (ms)2 (p < 0.05). HF values tended to increase, though not significantly so. During the remainder of the day there was also a non-statistically significant increment in all values of heart rate variability.

CONCLUSIONS

The study results suggest that patients with severe symptomatic aortic stenosis present with autonomic dysfunction that tends to normalize within the first year of valve replacement.

[The first Chilean journal of psychiatry, neurology and forensic medicine]

This historical review refers to the first Chilean Journal of Psychiatry, Neurology and Forensic Medicine, that was published for the first time in July 1917, and allows to get acquainted of the knowledge level of those times. The publication was in charge of physicians from "Casa de Orates", the Clinic of Nervous and Mental diseases and the Chair of Forensic Medicine. The journal publication was interrupted in 1919. More than half of papers were of psychiatric topics, reviewing a disease or updating treatments. Analysis of psychiatric themes showed a special interest for problems related to hospital management and mental health.

Subcellular distribution of prostaglandin-E2 and prostaglandin-F2 alpha in atrial tissue from patients with mitral valve disease

The distribution of prostaglandin-E2 (PGE2) and prostaglandin-F2 alpha (PGF2 alpha) was studied in subcellular fractions isolated from homogenates of human atrial fresh tissue by differential centrifugation. Right and left atrial samples were excised from the same heart of six patients with mitral valve disease at the time of open heart surgery. The atrial fractions investigated were mitochondrial (8,500 g pellet), microsomal (100,000 g pellet) and cytosol soluble (100,000 g supernatant) fractions. After extraction of prostaglandins from the three atrial fractions and separation of PGE from PGF series by chromatography on silicic acid column, these prostaglandins were measured by radioimmunoassay. The results showed that PGE2 and PGF2 alpha were located mainly in the soluble cytosolic fraction of right and left atrial tissue (p < 0.001). Furthermore, the prostaglandins levels were higher in left than in right atria of these patients (p < 0.001). The relation between prostaglandins heart generation in response to elevated work load of mitral valve disease is discussed.