Comparison between thermophysical and tribological properties of two engine lubricant additives: electrochemically exfoliated graphene and molybdenum disulfide nanoplatelets.

Recently graphene and other 2D materials were suggested as nano additives to enhance the performance of nanolubricants and reducing friction and wear-related failures in moving mechanical parts. Nevertheless, to our knowledge there are no previous studies on electrochemical exfoliated nanomaterials as lubricant additives. In this work, engine oil-based nanolubricants were developed via two-steps method using two different 2D nanomaterials: a carbon-based nano additive, graphene nanoplatelets (GNP) and a sulphide nanomaterial, molybdenum disulfide (MoS2) nanoplatelets (MSNP). The influence of these nano additives on the thermophysical properties of the nanolubricants, such as viscosity index, density and wettability, was investigated. The unique features of the electrochemical exfoliated GNP and MSNP allow the formulation of nanolubricant with unusual thermophysical properties. Both the viscosity and density of the nanolubricants decreased by increasing the nanoplatelets loading. The effect of the nano additives loading and temperature on the tribological properties of nanolubricants was investigated using two different test configurations: reciprocating ball-on-plate and rotational ball-on-three-pins. The tribological specimens were analysed by scanning electron microscopy (SEM) and 3D profiler in order to evaluate the wear. The results showed significant improvement in the antifriction and anti-wear properties, for the 2D-materials-based nanolubricants as compared with the engine oil, using different contact conditions. For the reciprocal friction tests, maximum friction and worn area reductions of 20% and 22% were achieved for the concentrations of 0.10 wt% and 0.20 wt% GNP, respectively. Besides, the best anti-wear performance was found for the nanolubricant containing 0.05 wt% MSNP in rotational configuration test, with reductions of 42% and 60% in the scar width and depth, respectively, with respect to the engine oil.

Hierarchical NiO/CMK-3 Photocathode for a p-Type Dye-Sensitized Solar Cell with Improved Photoelectrochemical Performance and Fast Hole Transfer.

The sluggish photoelectrochemical performance of p-type dye-sensitized solar cells (p-DSSCs) has hindered its commercial use. In this work, we introduce a novel hierarchical nanocomposite of NiO nanoparticles anchored on highly ordered mesoporous carbons CMK-3 (NiO/CMK-3). Using CMK-3 as a backbone effectively prevented the self-aggregation of NiO nanoparticles and subsequently increased the total specific surface area of the composite for more dye adsorption. The interconnected conductive networks of CMK-3 also served as a split-flow high-speed channel, which was beneficial for hole spin-flow to accelerate hole transfer. The hierarchical NiO/CMK-3 photocathode improved the photovoltaic conversion efficiency to 1.48% in a cell with a Cobalt(II)/(III) electrolyte and a PMI-6T-TPA dye.

Identification of matrix metalloproteinase-12 as a candidate molecule for prevention and treatment of cardiometabolic disease.

Obesity is strongly associated with metabolic syndrome, a combination of risk factors that predispose to the development of the cardiometabolic diseases: atherosclerotic cardiovascular disease and type 2 diabetes mellitus. Prevention of metabolic syndrome requires novel interventions to address this health challenge. The objective of this study was the identification of candidate molecules for the prevention and treatment of insulin resistance and atherosclerosis, conditions that underlie type 2 diabetes mellitus and cardiovascular disease, respectively. We used an unbiased bioinformatics approach to identify molecules that are upregulated in both conditions by combining murine and human data from a microarray experiment and meta-analyses. We obtained a pool of eight genes that were upregulated in all the databases analysed. This included well known and novel molecules involved in the pathophysiology of type 2 diabetes mellitus and cardiovascular disease. Notably, matrix metalloproteinase 12 (MMP12) was highly ranked in all analyses and was therefore chosen for further investigation. Analyses of visceral and subcutaneous white adipose tissue from obese compared to lean mice and humans convincingly confirmed the up-regulation of MMP12 in obesity at mRNA, protein and activity levels. In conclusion, using this unbiased approach an interesting pool of candidate molecules was identified, all of which have potential as targets in the treatment and prevention of cardiometabolic diseases.

Common dysregulated pathways in obese adipose tissue and atherosclerosis.

BACKGROUND: The metabolic syndrome is becoming increasingly prevalent in the general population that is at simultaneous risk for both type 2 diabetes and cardiovascular disease. The critical pathogenic mechanisms underlying these diseases are obesity-driven insulin resistance and atherosclerosis, respectively. To obtain a better understanding of molecular mechanisms involved in pathogenesis of the metabolic syndrome as a basis for future treatment strategies, studies considering both inherent risks, namely metabolic and cardiovascular, are needed. Hence, the aim of this study was to identify pathways commonly dysregulated in obese adipose tissue and atherosclerotic plaques. METHODS: We carried out a gene set enrichment analysis utilizing data from two microarray experiments with obese white adipose tissue and atherosclerotic aortae as well as respective controls using a combined insulin resistance-atherosclerosis mouse model. RESULTS: We identified 22 dysregulated pathways common to both tissues with p values below 0.05, and selected inflammatory response and oxidative phosphorylation pathways from the Hallmark gene set to conduct a deeper evaluation at the single gene level. This analysis provided evidence of a vast overlap in gene expression alterations in obese adipose tissue and atherosclerosis with Il7r, C3ar1, Tlr1, Rgs1 and Semad4d being the highest ranked genes for the inflammatory response pathway and Maob, Bckdha, Aldh6a1, Echs1 and Cox8a for the oxidative phosphorylation pathway. CONCLUSIONS: In conclusion, this study provides extensive evidence for common pathogenic pathways underlying obesity-driven insulin resistance and atherogenesis which could provide a basis for the development of novel strategies to simultaneously prevent type 2 diabetes and cardiovascular disease in patients with metabolic syndrome.

An extensive hemimelic polyostotic fibrous dysplasia: a case report.

We report a new case of polyostotic fibrous dysplasia (FD). A 26-year-old woman was referred to our department complaining of pain in her left arm. She had suffered for tow fractures in left leg and arm previously. Plain radiographs showed osteolytics lesions at the left humerus and radius. Histological examination of the surgical specimens showed FD. She has beneficed with zoledronic acid perfusion.

Ultraviolet irradiation of diacetylenic liposomes as a strategy to improve size stability and to alter protein binding without cytotoxicity enhancement.

Membrane-modification effects, induced by ultraviolet (UV) irradiation in diacetylenic liposomes, were analyzed upon contact with cells, biological membranes, and proteins. Liposomes formulated with mixtures of unsaturated 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine and saturated 1,2-dimyristoyl-sn-glycero-3-phosphocholine, in a 1:1 molar ratio, were compared with those that were UV-irradiated and analyzed in several aspects. Membrane polymerization inherence on size stability was studied as well as its impact on mitochondrial and microsomal membrane peroxidation induction, hemolytic activity, and cell viability. Moreover, in order to gain insight about the possible irradiation effect on interfacial membrane properties, interaction with bovine serum albumin (BSA), lysozyme (Lyso), and apolipoprotein (apoA-I) was studied. Improved size stability was found for polymerized liposomes after a period of 30 days at 4°C. In addition, membrane irradiation had no marked effect on cell viability, hemolysis, or induction of microsomal and mitochondrial membrane peroxidation. Interfacial membrane characteristics were found to be altered after polymerization, since a differential protein binding for polymerized or nonpolymerized membranes was observed for BSA and Lyso, but not for apoA-I. The substantial contribution of this work is the finding that even when maintaining the same lipid composition, changes induced by UV irradiation are sufficient to increase size stability and establish differences in protein binding, in particular, reducing the amount of bound Lyso and BSA, without increasing formulation cytotoxicity. This work aimed at showing that the usage of diacetylenic lipids and UV modification of membrane interfacial properties should be strategies to be taken into consideration when designing new delivery systems.

Assessing human genetic diversity in Tunisian Berber populations by Alu insertion polymorphisms.

BACKGROUND: The most recent Alu insertions reveal different series of characteristics such as stability that make them particularly suitable genetic markers for human biological studies. AIM: Six human-specific Alu insertion polymorphisms were typed in two Tunisian Berber populations with the aim of analysing the genetic diversity of these two communities and the genetic relationships between this region of North Africa and other populations. SUBJECTS AND METHODS: Forty-seven Berbers from Sejnane and 33 from Takrouna were sampled. Alu insertion polymorphism was analysed using PCR with loci specific primers. RESULTS: A similar level of gene diversity was detected in Sejnane and Takrouna populations. PC results revealed genetic affinities between these two populations and some Eurasian populations (Germany, Genova and Syria). In contrast, there is a differentiation between these two Berber communities and North African and Iberian populations. CONCLUSION: The results of this study confirm the heterogeneity of Berbers in North Africa, which suggests their diverse origins. In the case of Sejnane and Takrouna populations, these results are in line with an ancient Euro Mediterranean background that has already been studied by archaeologists, particularly for the population of Sejnane.

[Parotid mucormycosis: A new case and review of the literature]. / Mucormycose parotidienne : une nouvelle observation et revue de la littérature.

INTRODUCTION: Mucormycosis is a rare, devastating, fungal infection, which disproportionately affects non-controlled diabetic patients, notably during ketoacidosis. The authors report the case of cervical mucormycoses with a particularly favorable evolution in diabetic woman. REPORT: A 54-year-old woman, type 2 diabetic, had presented a left lateral cervical mass. The diagnosis was confirmed by histological examination. She was treated with Amphotericin B with favorable evolution. CONCLUSION: The mucormycose is a rare infection. The treatment is medical and surgical. The prognosis is severe with an overall mortality rate of 40%.

Rhinocerebral mucormycosis: five cases and a literature review.

OBJECTIVE: In this retrospective study, we describe our experience in the diagnosis and management of rhinocerebral mucormycosis (RCM), a rapidly lethal fungal infection. METHODOLOGY: Between 1997 and 2007, five patients hospitalized for suspicion of RCM. Computed tomography was performed in all cases, and diagnosis was confirmed after anatomopathological or mycological examination. All patients underwent medical and surgical treatment. Follow-up was clinical and radiological with a mean period of 17 months. RESULTS: All patients were diabetic. Exophthalmia, rhinorrhea, and ophthalmoplegia were the most frequent symptoms observed. One patient had loss of visual acuity and another exhibited peripheral facial palsy. One patient had extensive hemifacial cutaneous necrosis. Nasal endoscopy revealed black necrotic lesions in one case, and another patient had a tumefaction localised in the left middle meatus. Necrotic lesions were most often found in the orbit, the maxillary and the ethmoidal sinuses on computed tomography (four cases for each site). One patient had thrombophlebitis of the cavernous sinus, and another had an intracranial extension. All patients were administered ordinary insulin and intravenous amphotericin B. Surgical debridement of the nasal cavity and the involved sinuses was performed through lateral rhinotomy (four cases) or endoscopy (one case). Unilateral orbital exenteration was associated in two cases. Progression was favourable in four cases; one patient died from sepsis despite aggressive treatment. CONCLUSION: Early diagnosis is crucial for the management of RCM. Treatment of underlying disorders, use of intravenous amphotericin B, and aggressive surgical intervention are key in reducing morbidity and mortality rates.

Haemoperitoneum caused by spontaneous haemorrhage of the greater omentum: a rare complication occurring in a patient with severe SARS-CoV-2 infection.

Haemorrhagic events in patients diagnosed with coronavirus disease 19 (COVID-19) are infrequent but reports have accumulated since the beginning of the pandemic. The pathophysiological mechanisms are unclear, but endothelial damage secondary to systemic vasculitis and the onset of anticoagulation therapy, both associated with severe forms of the infection, have been proposed to play a role in the development of this complication. We present the case of a 66-year-old man who presented to the emergency department with acute abdominal pain, hypotension and decrease of consciousness, a few hours after being discharged after a prolonged hospitalisation of 26 days due to severe SARS-CoV-2 pneumonia. Initial resuscitation was carried out and, when haemodynamic stabilisation was achieved, a computed tomography scan showed contrast extravasation at the topography of the greater omentum. Urgent angiography revealing contrast extravasation originating in a pseudoaneurysm dependent on the right gastroepiploic artery was done, and embolisation with cyanoacrylate was performed at the bleeding point. Owing to persistent haemodynamic instability despite angiographic treatment and aggressive resuscitation, emergency laparotomy was indicated. Partial resection of the greater omentum was carried out and histopathologic examination showed a 5cm×4cm×6cm haematoma, with no signs of abnormalities such as aneurysm or malignancy. No rebleeding occurred. Spontaneous haemorrhage of the greater omentum associated with haemoperitoneum is a serious condition, with reported mortality rates exceeding 30%. This case highlights a very infrequent but potentially life-threatening complication in a patient diagnosed with COVID-19 on anticoagulation therapy.

Molecular analysis in two Tunisian families with combined factor V and factor VIII deficiency.

SUMMARY: Combined factor V (FV) and factor VIII (FVIII) deficiency (F5F8D) is a rare autosomal recessive disorder caused by mutations in LMAN1 or MCFD2 genes which encode proteins that form a complex involved in the transport of FV and FVIII from the endoplasmic reticulum to Golgi apparatus. We report two novel mutations in MCFD2 gene and one recurrent mutation in LMAN1 gene that caused combined FV and FVIII deficiency in two unrelated Tunisian Muslim families. For the first family two patients were homozygous for a new missense mutation Asp81His in exon 3 of MCFD2 and heterozygous for a second new missense mutation Val100Asp in the same exon. Replacement respectively of the hydrophilic Asp residue with hydrophobic positively charged His and of the hydrophobic neutral Val residue with the Asp residue most likely disrupts the MCFD2-LMAN1 interaction, thus leading to the disease phenotype. For the second family a reported Arg202X mutation in exon 5 in the LMAN1 gene was identified in the homozygous state.

[Phosphorus magnetic resonance spectroscopy: Brain pathologies applications]. / Spectroscopie du phosphore 31 par résonance magnétique : applications en pathologies cérébrales.

Until recent years, brain applications of (31)P magnetic resonance spectroscopy were poor. Arising of clinical high field strength magnets (three Tesla) as well as dedicated brain coils (eg: bird cage), using specific and useful sequences providing appropriate spatial localisation and signal to noise ratio brought highlights on multinuclear spectroscopy. Better understanding of brain metabolism emphasizes the role of phosphoenergetic compounds and its potential issues in tumoral, metabolic and degenerative diseases. In the present paper, we report 1 year of experience and preliminary results for 40 patients as well as review of the literature. By successive in vivo determination and quantitation of numerous metabolites it allows, multinuclear spectroscopy may provide additional information to biomathematical models of brain metabolism.

The masticator space: from anatomy to pathology.

The masticator space is a deep facial space with a complex anatomical structure. The purpose of the present study was to precisely define the masticator space to eliminate the use of obsolete and confusing terms to describe the area, and to illustrate the common mass syndromes. Primary tumors are uncommon, usually benign and of a vascular or neural origin. Adjacent lesions, mainly pharyngeal with secondary extension into the masticator space, are especially frequent. Metastases are rare, and infectious pathology is often odontogenic. The most frequent lesion of the masticator space is the odontogenic abscess. Multidetector CT and MRI enable precise study of the space, its communications with other deep spaces and the etiology of any mass syndrome. Understanding the anatomy of the masticator space and how it links up with the other deep facial spaces helps the radiologist to recognize the different lesions of this space and to avoid unnecessary surgery, or any other less than optimal management.

Influence of airflow rate and substrate nature on heterogeneous struvite precipitation.

In wastewater treatment plants a hard scale consisting of struvite crystals can be formed, in pipes and recirculation pumps, during anaerobic digestion of wastewater. This study was conducted to evaluate the effect of airflow rate and substrate nature on nucleation type, induction period and supersaturation coefficient during struvite precipitation. A crystallization reactor similar to that designed for calcium carbonate precipitation was used. The pH of synthetic wastewater solution was increased by air bubbling. Experimental results indicated that the airflow increased heterogeneous precipitation of struvite. The susceptibility to scale formation was more important on polyamide and polyvinyl chloride than on stainless steel. In all cases, X-ray diffraction and infrared spectroscopy showed that the precipitated solid phase was solely struvite. No difference in crystal morphology was observed. However, at similar experimental conditions, the particle size of struvite was higher for stainless-steel material than that for plastic materials.

[Imaging of odontogenic tumors of the maxilla]. / Imagerie tumorale odontogénique des maxillaires.

Odontogenic tumors of the maxilla are frequent, mainly represented by cysts of the jaw. However, this group of tumors include a large number of potentially intricate pathologies whose evolution is dominated by frequent recurrences justifying long-term follow-up. When such a lesion is discovered, evaluation of imaging features combined with an extensive knowledge of the different patterns of other lesions (particularly their potentially evolutive patterns related to growth) can often suggest the diagnosis. While definitive diagnosis frequently relies on histology, it is not rare that the patterns are so intricate that final diagnosis is based on a correlation between clinical, imaging and histological findings.

[Utility of bone SPECT-CT in percutaneous vertebroplasty]. / Utilidad de la SPECT-TAC ósea en la vertebroplastia percutánea.

Percutaneous vertebroplasty is a minimally invasive procedure that has shown excellent results in the treatment of back pain due to acute-subacute vertebral fracture. The bone scintigraphy shows the increase of metabolic exchange in the fracture. The new hybrid SPECT-CT equipment combines bone SPECT images with Computed Tomography (CT), making it possible to obtain more combined, functional and anatomical information. We present 5 selected patients studied by bone SPECT-CT in whom fused images made it possible to obtain a more precise localization of the pain origin, and thus assess other possible causes of the vertebral pain or even reassess the vertebroplasty indication.

Datos de remisión y manejo de una población oncológica a una unidad de dolor. ¿Qué podemos mejorar? / Review of the remission and management of a cancer related pain population to a pain unit. What can we improve?

Objetivos: Determinar las características demográficas, clínicas y de manejo analgésico de una población con dolor oncológico remitida a nuestra unidad de dolor (UD). Descripción de su manejo clínico una vez recibidos en la unidad. Detectar aspectos de mejora.Material y métodos: Estudio retrospectivo y descriptivo, realizado durante un periodo de 23 meses, entre noviembre de 2019 y diciembre de 2021, de todos los pacientes oncológicos derivados a la UD, cuya causa de derivación fuera dolor de origen oncológico.Resultados: Se analizaron 78 pacientes, el 63,2 % hombres y el 46,8 % mujeres. La edad media poblacional fue de 64,84 ± 12,623 años. El 44,7 % fueron remitidos por servicios quirúrgicos. El 75 % presentaba dolor moderado o severo. Los tumores más frecuentes fueron los abdominales (31,6 %), y cabeza y cuello (22,4 %). La causa del dolor fue en 48,7 % de los casos de la infiltración tumoral y en un 60,5 % un dolor de origen de mixto. En el momento de la remisión el 60 % de los pacientes recibía opioides mayores, con una dosis de equivalentes diarios de morfina (EDM) de 163,57 ± 167,10 mg y el 38 % recibía antineuropáticos. El tiempo medio para atender a estos pacientes desde el momento de solicitarla fue de 9,18 ± 9,73 días. Se realizó intervencionismo menor en el 56,6 % (43) de los pacientes y mayor en el 2,6 % (2). Se inició en la UD el tratamiento con fármacos antineuropáticos en el 68,4 % de los casos. Tras el manejo en la UD, un 72,4 % de los pacientes refirieron mejoría del dolor.Conclusiones: Mejorar la tasa de remisión de pacientes desde servicios como Oncología médica y Atención primaria. Mejorar los tiempos de remisión a las unidades de dolor. Ajustar mejor los tratamientos analgésicos antes de la remisión. Generar un protocolo de remisión sencillo de pacientes que incluyan pautas básicas de manejo del dolor. Mejorar el diagnóstico de dolor neuropático. Aumentar la cartera de servicios de intervencionismos de la UD....(AU)

Aim: Studying the demographic profile, clinical characteristics and analgesic management of an oncologic population sent to our pain unit. To describe the pain management in our unit. To detect management aspects to be improved.Methodology: Retrospective and descriptive study, performed in a period of 23 months, between November 2019 and December 2021, of all patients sent to our pain unit for cancer pain management.Results: A total of 78 patients were analyzed, 63,2 % men and 46,8 % women. The average age was 64,84 ± 12,623 years. 44,7 % were sent by surgical services. In 75% the pain was moderate or severe. The main cancer location was abdominal (31,6 %), and head and neck (22,4 %). In 48,7 % the pain was originated by tumoral infiltration and in 60,5 % the pain was judged to be mixed. At the moment of the arrival 60 % of patients were on opioids, with an average dose of 163,57 ± 167,10 mg EDM and 38 % were on antineurophatic drugs. The average time to attend the patients from the moment or request was 9,18 ± 9,73 days. A minor interventional procedure was performed in 56,6 % (43) of the patients, and a major intervention in 2,6 % (2). We started antineurophatic drugs in 68,4 % of the cases. During the period of pain management in our unit a 72,4% of the patients referred an improvement of their cancer related pain.Conclusions: It is necessary to improve the rate of remission from medical oncology departments and primary care physicians. To reduce the remission time to our unit from the referral services. To improve analgesic management before referral. To create an easy protocol for remission of patients that includes basic pain management instructions. To improve the rate of neuropathic pain diagnosis before referral. To expand our interventional technics portfolio. Pain units can improve cancer related pain management. To create multidisciplinary cancer pain comities.(AU)

Perfusion MR imaging at 3-Tesla: Can it predict tumor grade and histologic necrosis rate of musculoskeletal sarcoma?

PURPOSE: To identify quantitative perfusion parameters that are best associated with tumor grade and tumor necrosis at magnetic resonance (MR) imaging at 3-Tesla. METHODS: MR perfusion studies of 31 patients with a musculoskeletal sarcoma were retrospectively evaluated by two readers. There were 18 men and 13 women with a mean age of 34.9±24.4 (standard deviation [SD] years) (range: 6-87 years). All patients underwent carcinologic tumor resection less than 3 months after MR imaging. For all patients six perfusion parameters (three semi-quantitative and three permeability parameters) were analyzed. The percentage of tumor necrosis was estimated using MR imaging. Perfusion data were compared between groups of tumors with different grades and necrosis ratios. Interobserver variability was calculated using intraclass correlation coefficient (ICC). RESULTS: Interobserver variability among the perfusion parameters was good to excellent (ICC: 0.72-0.9). The area under the curve and maximum slope values showed a significant association with the degree of tumor necrosis (P=0.02-0.04). When tumors with low necrosis ratios were compared to those with high ratios the former parameter was 80% lower. In the same groups, the imaging necrosis index was 56.9-59.8% higher in patients with grade 2 necrosis (P=0.01). Extracellular space volume (Ve) was 31.4% to 55.8% lower in tumors with high grade while the backflow constant (Kep) was 33.6% to 40.1%% higher in tumors with high grade. CONCLUSION: Semi-quantitative MR perfusion parameters have an excellent reproducibility and are associated with the degree of histologic tumor necrosis in musculoskeletal sarcomas. The utility of permeability parameters for determining tumor grade needs further investigations.

Developing and testing a model of quality of life among chronically-ill, community-dwelling older adults: A structural equation model.

PURPOSE: Although healthy ageing aims for better quality of life, the inability of older adults to adequately care for themselves and their health impair the realization of such objective. Moreover, in a collectivist community like the Philippines, the family, community, and Transcendent are inseparable in promoting quality of life. This study developed and tested a model of quality of life (QoL) among chronically-ill, community-dwelling older adults. MATERIALS AND METHODS: From August to November 2017, a cross-sectional study of 304 chronically-ill, community-dwelling older adults from selected rural communities in the Philippines was conducted. Respondents completed a five-part survey packet composed of the socio-demographic profile, modified Older People's Quality of Life, Spirituality Assessment Scale, Hypertension Self-Care Profile, and Diabetes Self-Management Questionnaire. RESULTS: Socio-demographics, community satisfaction, spirituality, and disease self-management accounted 29.00% of QoL, generating a good model (χ2/df = 1.44, RMSEA = 0.038, and PNFI = 0.64). Spirituality (ß = 0.34, p < 0.01) was the strongest predictor of QoL, while community satisfaction had both direct (ß = 0.26, p < 0.01) and indirect (ß = 0.08, p < 0.01) effects. Disease self-management directly (ß = 0.15, p = 0.016) influenced QoL. In contrast, longer chronicity and larger family size impair QoL. CONCLUSION: Quality of life among chronically-ill, community-dwelling older adults is a multi-faceted health construct influenced by socio-demographics, disease self-management, community satisfaction, and spirituality. The presented model highlights the positive effect of disease self-management, community satisfaction, and spirituality which can be utilized in developing appropriate community-based geriatric strategies, policies, and programs. Further, forming collaborative groups with socially-active community elderly and community-based self-care programs can be ventured to address the needs of older adults.

Nonsense mutation causing steroid 21-hydroxylase deficiency.

We determined the sequence of a mutant CYP21B gene isolated from a patient with the severe, "salt-wasting" form of congenital adrenal hyperplasia due to steroid 21-hydroxylase deficiency. Codon 318 in this gene is changed from CAG, encoding glutamine, to TAG, a nonsense codon. This is predicted to result in a completely nonfunctional enzyme due to premature termination of translation. In addition, when the cloned mutant gene was transfected into mouse Y1 adrenal cells, the resulting mRNA levels were decreased compared with transfected normal CYP21B genes. This mutation was carried by 3 of 20 unrelated patients with 21-hydroxylase deficiency alleles as determined by hybridization with a specific oligonucleotide probe. This mutation is also seen in the normal CYP21A pseudogene, so that its presence in the abnormal CYP21B gene may be the result of a gene conversion event.