Transosseous Cannula Suture Suspensionplasty for Thumb Basal Joint Arthritis: A Novel Technique.

The suture button (SB) suspension technique has become popular in the treatment of thumb basal joint arthritis, as it works as an internal mean for metacarpal stabilization, demonstrating good results with improvement in function and strength. The aim of our study is to describe a new transosseous suture suspensionplasty technique using a simple Ethibond #2 suture as a substitute for the suture button and to report the postoperative clinical outcomes. In this study, we included a total of 14 patients with 2 years follow-up. We evaluated patients with the use of the Disabilities of the Arm, Shoulder and Hand questionnaire, the Visual Analog Scale, the Kapandji test, and the key pinch strength. Patients treated with transosseous suture suspensionplasty demonstrated clinical improvement at an average follow-up of 24 months. No complications were noted immediately after the procedure or during the 2-year follow-up period.

Lignin-Based Nanoparticles as Both Structural and Active Elements in Self-Assembling and Self-Healing Multifunctional Hydrogels for Chronic Wound Management.

Efficient wound healing is feasible when the dressing materials simultaneously target multiple factors causing wound chronicity, such as deleterious proteolytic and oxidative enzymes and bacterial infection. Herein, entirely bio-based multifunctional self-assembled hydrogels for wound healing were developed by simply mixing two biopolymers, thiolated hyaluronic acid (HA-SH) and silk fibroin (SF), with lignin-based nanoparticles (NPs) as both structural and functional elements. Sono-enzymatic lignin modification with natural phenolic compounds results in antibacterial and antioxidant phenolated lignin nanoparticles (PLN) capable of establishing multiple interactions with both polymers. These strong and dynamic polymer-NP interactions endow the hydrogels with self-healing and shear-thinning properties, and pH-responsive NP release is triggered at neutral to alkaline pH (7-9). Despite being a physically crosslinked hydrogel, the material was stable for at least 7 days, and its mechanical and functional properties can be tuned depending on the polymer and NP concentration. Furthermore, human skin cells in contact with the nanocomposite hydrogels for 7 days showed more than 93% viability, while the viability of clinically relevant Staphylococcus aureus and Pseudomonas aeruginosa was reduced by 99.7 and 99.0%, respectively. The hydrogels inhibited up to 52% of the activity of myeloperoxidase and matrix metalloproteinases, responsible for wound chronicity, and showed a strong antioxidant effect, which are crucial features promoting wound healing.

Antibacterial lignin-based nanoparticles and their use in composite materials.

Lignin, one of the most abundant biopolymers on earth, has been traditionally considered a low-value by-product of the pulp and paper industries. This renewable raw material, besides being a source of valuable molecules for the chemical industry, also has antioxidant, UV-absorbing, and antibacterial properties in its macromolecular form. Moreover, lignin in the form of nanoparticles (LigNPs) presents advantages over bulk lignin, such as higher reactivity due to its larger surface-to-volume ratio. In view of the rapid surge of antimicrobial resistance (AMR), caused by the overuse of antibiotics, continuous development of novel antibacterial agents is needed. The use of LigNPs as antibacterial agents is a suitable alternative to conventional antibiotics for topical application or chemical disinfectants for surfaces and packaging. Besides, their multiple and unspecific targets in the bacterial cell may prevent the emergence of AMR. This review summarizes the latest developments in antibacterial nano-formulated lignin, both in dispersion and embedded in materials. The following roles of lignin in the formulation of antibacterial NPs have been analyzed: (i) an antibacterial active in nanoformulations, (ii) a reducing and capping agent for antimicrobial metals, and (iii) a carrier of other antibacterial agents. Finally, the review covers the inclusion of LigNPs in films, fibers, hydrogels, and foams, for obtaining antibacterial lignin-based nanocomposites for a variety of applications, including food packaging, wound healing, and medical coatings.

3D-Printed Polymer-Infiltrated Ceramic Network with Antibacterial Biobased Silver Nanoparticles.

This work aimed at the antimicrobial functionalization of 3D-printed polymer-infiltrated biomimetic ceramic networks (PICN). The antimicrobial properties of the polymer-ceramic composites were achieved by coating them with human- and environmentally safe silver nanoparticles trapped in a phenolated lignin matrix (Ag@PL NPs). Lignin was enzymatically phenolated and used as a biobased reducing agent to obtain stable Ag@PL NPs, which were then formulated in a silane (γ-MPS) solution and deposited to the PICN surface. The presence of the NPs and their proper attachment to the surface were analyzed with spectroscopic methods (FTIR and Raman) and X-ray photoelectron spectroscopy (XPS). Homogeneous distribution of 13.4 ± 3.2 nm NPs was observed in the transmission electron microscopy (TEM) images. The functionalized samples were tested against Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa) bacteria, validating their antimicrobial efficiency in 24 h. The bacterial reduction of S. aureus was 90% in comparison with the pristine surface of PICN. To confirm that the Ag-functionalized PICN scaffold is a safe material to be used in the biomedical field, its biocompatibility was demonstrated with human fibroblast (BJ-5ta) and keratinocyte (HaCaT) cells, which was higher than 80% in both cell lines.

Chronic exertional compartment syndrome of the forearm: a systematic review.

The aim of this systematic review is to understand which surgical procedure provides better results in terms of pain relief and function in the treatment of chronic exertional compartment syndrome (CECS) of the forearm.We searched Medline (PubMed), Web of Science, Embase and Scopus databases on 8 July 2020. Twelve studies were included in this review.We assessed the quality of the studies using the Coleman Methodological Score.Data on demographic features, operative readings, diagnostic methods, follow-up periods, type and rates of complications, survivorship of the procedure, return to sport activity, and outcome measures were recorded.In conclusion, compared to the other techniques, endoscopic fasciotomy delivers similar success rates and lower incidence of complications. Cite this article: EFORT Open Rev 2021;6:101-106. DOI: 10.1302/2058-5241.6.200107.

Hybrid Tellurium-Lignin Nanoparticles with Enhanced Antibacterial Properties.

The surge of antibiotic-resistant bacteria is leading to the loss of effectiveness of antibiotic treatment, resulting in prolonged infections and even death. Against this healthcare threat, antimicrobial nanoparticles that hamper the evolution of resistance mechanisms are promising alternatives to antibiotics. Herein, we used Kraft lignin, a poorly valorized polymer derived from plant biomass, to develop novel hybrid tellurium-lignin nanoparticles (TeLigNPs) as alternative antimicrobial agents. The sonochemically synthesized TeLigNPs are comprised of a lignin matrix with embedded Te clusters, revealing the role of lignin as both a reducing agent and a structural component. The hybrid NPs showed strong bactericidal effects against the Gram-negative Escherichia coli and Pseudomonas aeruginosa, achieving more than 5 log bacteria reduction, while they only slightly inhibited the growth of the Gram-positive Staphylococcus aureus. Exposure of TeLigNPs to human cells did not cause morphological changes or reduction in cell viability. Studies on the antimicrobial mechanism of action demonstrated that the novel TeLigNPs were able to disturb bacterial model membranes and generate reactive oxygen species (ROS) in Gram-negative bacteria.

Percutaneous Radiofrequency Ablation of the Posterior and Anterior Interosseous Nerves for Chronic Wrist Pain: A Novel Technique.

The treatment of chronic wrist pain, due to posttraumatic, degenerative, or inflammatory arthritis, is challenging to adequately manage. The ideal surgical procedure should preserve wrist mobility and provide long-lasting pain relief. In this regard, denervation aims to decrease wrist pain by interrupting sensory innervation, without impairing motor function, and avoids the need for postoperative immobilization to decrease the risk of stiffness. For these reasons, denervation is particularly attractive as a possible treatment for chronic wrist pain. Our aim was to describe our novel technique for partial percutaneous wrist denervation, performed by radiofrequency ablation of the posterior and anterior interosseous nerves, and to report on the prospective outcomes over a 1-year follow-up for 3 patients (4 wrists) treated as of March 2019. The technique is performed on an outpatient basis and does not require postprocedure wrist immobilization or restriction in activities of daily living or work. Findings at the 1-year follow-up indicate that partial denervation improved grip strength, provided pain relief, maintained wrist motion, and improved subjective report of disabilities of the arm, shoulder, and hand. One patient did not report a benefit of the procedures, with other patients being very satisfied. Our percutaneous procedure is an evolution of the traditional partial denervation technique, providing advantages of being less invasive, not requiring restriction of movement or activities in the postoperative phase, can be performed on an out-patient basis, and does not preclude the subsequent use of invasive surgical procedures, as needed.

Partial trapeziectomy and pyrocarbon interpositional arthroplasty for trapeziometacarpal osteoarthritis: minimum 8-year follow-up.

We undertook a retrospective study to evaluate minimal 8-year outcomes of 46 trapeziometacarpal joints (46 patients) treated with pyrocarbon implant arthroplasty after partial trapeziectomy for trapeziometacarpal joint osteoarthritis in two different hand surgery units. The mean follow-up interval was 9.5 years (average 113 months with a range 97-144 months). The study showed that pyrocarbon interpositional arthroplasty provided pain relief and high patient satisfaction. All patients experienced a reduction in the DASH score, with an average change of 30 points. The visual analogue scale score, the Kapandji score, and key pinch also showed remarkable improvement. The PyroDisk implant exhibited good longevity, with good implant survival. A review of the literature revealed that the functional outcomes after implant surgery are not superior to more common techniques, such as trapeziectomy with or without ligamentoplasty. Therefore, this is a reliable surgery but may not have added benefits over simpler surgical treatments. This implant could have a role, perhaps in a select group of young patients, as a time-procuring procedure. Level of evidence: IV.

[Early detection and stability of diagnosis in autism spectrum disorders]. / Deteccion precoz y estabilidad en el diagnostico en los trastornos del espectro autista.

INTRODUCTION: Early intervention for children with an autism spectrum disorder (ASD) depends on early and reliable detection. In general, diagnosis is stable, but evidence shows the need to go deeper into the factors that influence this stability. PATIENTS AND METHODS: A sample of 142 children with ASD (118 boys and 24 girls) with a median of 33 months of age and an interquartile range of 12 in the first evaluation. In the follow-up the median was 47 months and an interquartile range of 29. The following tests were applied to evaluate the children: Merrill-Palmer Scale-R, Leitter-R, WIPPSI-III, WISC-R and WISC-IV; as well as Vineland Scale and ADOS-G, based on clinical diagnosis to DSM-IV-R and DSM-5. For the evaluation of the diagnostic stability, contingency tables were performed for diagnostic assessments based on clinical judgment and the results of the ADOS-G. Repeated measures ANOVA was used to analyze the differences between measures of cognitive functioning, adaptive behavior and diagnosis. RESULTS: The clinical diagnosis based on DSM-IV-TR, DSM-5 and clinical judgment remains stable over time in 96% of cases. If the diagnostic stability is measured based on the results of ADOS-G (n = 30), 87% of cases diagnosed maintained the diagnosis. The ANOVA showed statistically significant differences for measures of within-subject factors and global social age, but not for diagnosis. CONCLUSION: The diagnostic stability can be improved by utilizing clinical judgment and the participation of a multidisciplinary team.

TITLE: Deteccion precoz y estabilidad en el diagnostico en los trastornos del espectro autista.Introduccion. La intervencion temprana en los niños con un trastorno del espectro autista (TEA) depende de una deteccion precoz y fiable. Aunque de manera general se habla de un diagnostico estable, se ha evidenciado la necesidad de profundizar mas en los factores que influyen en dicha estabilidad. Pacientes y metodos. Los participantes de la muestra fueron 142 menores con TEA (118 varones y 24 mujeres), con una mediana de 33 meses y un recorrido intercuartilico de 12 en la primera evaluacion, y con una mediana de 47 meses y un recorrido intercuartilico de 29 en el seguimiento. Los diagnosticos se realizaron con las siguientes pruebas: escala Merrill-Palmer revisada, escala de Leiter revisada, escala de inteligencia de Wechsler para preescolar y primaria III y escala de inteligencia de Wechsler para niños revisada y IV; ademas de la escala Vineland y la escala de observacion diagnostica del autismo generica (ADOS-G), basandose el diagnostico clinico en los criterios diagnosticos del Manual diagnostico y estadistico de los trastornos mentales, cuarta edicion, texto revisado (DSM-IV-TR), y quinta edicion (DSM-5). Para la evaluacion de la estabilidad diagnostica, se realizaron tablas de contingencia para las valoraciones del diagnostico en funcion del juicio clinico y los resultados de la ADOS-G. Resultados. El diagnostico clinico basado en los criterios del DSM-IV-TR, el DSM-5 y el juicio clinico se mantiene estable a traves del tiempo en un 96% de los casos. Si se valora la estabilidad diagnostica teniendo en cuenta los resultados del ADOS-G (n = 30), el 87% de los casos mantiene el diagnostico. El ANOVA muestra diferencias estadisticamente significativas para las medidas del factor intrasujeto del cociente intelectual y la edad social global, pero no para el diagnostico. Conclusiones. La estabilidad diagnostica se beneficia de un uso informado del criterio clinico y de la participacion de un equipo multidisciplinar.

Influencia de la comorbilidad médica y neuropsiquiátrica en la evolución de la epilepsia infantil / Influence of medical and neuropsychiatric comorbidities on the course of childhood epilepsy

INTRODUCCIÓN: El creciente reconocimiento de la comorbilidad y su carga plantea la necesidad de incluir en el manejo de los pacientes con epilepsia su investigación, prevención y tratamiento. MATERIAL Y MÉTODOS: Estudio descriptivo de todos los pacientes con epilepsia, perteneciente a un área suburbana de la Comunidad de Madrid, seguidos en consulta al menos durante un año. Excluimos a menores de 2 años, las crisis febriles y sintomáticas agudas. RESULTADOS: Incluimos a 46 pacientes (54% varones y edad media 9,1 años). El 52,5% en monoterapia. El 45,7% «libre de crisis», el 23,9% epilepsia «farmacorresistente» y el 30,4% «indeterminada». El 28,3% tenía patología médica crónica asociada y un 41,3% neuropsiquiátrica. El 32,6% acudió de manera imprevista por crisis, con un riesgo de 15 y 8,3 veces mayor aquellos con comorbilidad médica crónica y neuropsiquiátrica respecto al de los pacientes sin comorbilidades. CONCLUSIONES: La comorbilidad puede desempeñar un papel importante en el curso de la epilepsia

INTRODUCTION: Comorbidity has a significant influence in the management of patients with epilepsy. MATERIAL AND METHODS: A descriptive study of all patients with epilepsy, from a suburban area in the Community of Madrid followed up for at least 1 year. Children under 2 years, those with symptomatic acute febrile seizures were excluded. RESULTS: Out of a total of 46 patients (54% male, age median 9.1 years), more than half (52.5%) were on monotherapy, 45.7% were ''free of seizures'', 23.9% had ''drug resistant epilepsy'', and 30.4% were ''undetermined''. As regards comorbidities, 28.3% had chronic medical conditions, and 41.3% associated neuropsychiatric disorders. In32.6%, the seizures were of sudden onset, and those with chronic medical and neuropsychiatric comorbidities had a risk of 15 and 8.3 times, respectively, than those patients without comorbidities. CONCLUSIONS: Comorbidities may have an important role in the course of epilepsy

[Influence of medical and neuropsychiatric comorbidities on the course of childhood epilepsy]. / Influencia de la comorbilidad médica y neuropsiquiátrica en la evolución de la epilepsia infantil.

INTRODUCTION: Comorbidity has a significant influence in the management of patients with epilepsy. MATERIAL AND METHODS: A descriptive study of all patients with epilepsy, from a suburban area in the Community of Madrid followed up for at least 1 year. Children under 2 years, those with symptomatic acute febrile seizures were excluded. RESULTS: Out of a total of 46 patients (54% male, age median 9.1 years), more than half (52.5%) were on monotherapy, 45.7% were "free of seizures", 23.9% had "drug resistant epilepsy", and 30.4% were "undetermined". As regards comorbidities, 28.3% had chronic medical conditions, and 41.3% associated neuropsychiatric disorders. In32.6%, the seizures were of sudden onset, and those with chronic medical and neuropsychiatric comorbidities had a risk of 15 and 8.3 times, respectively, than those patients without comorbidities. CONCLUSIONS: Comorbidities may have an important role in the course of epilepsy.

[The assessment of nursing workload]. / I carichi di lavoro infermieristico.

The measurement of nursing workload first began in the 1970s, because of the need for determining severity of illness and cost-effectiveness in the intensive care unit. In the following decades, the need for more specific tools for assessing nursing workload brought to the development of scoring systems more focused on nursing activities. We will briefly review the scoring systems validated since 1974. TISS-Therapeutic Intervention Scoring System elaborated by Cullen in 1974 is based on 57 therapeutic procedures and was designed to assess the severity of illness in the ICU. Each intervention scores 1 to 4. Patients are grouped in 5 classes. It was not sufficiently validated and was abandoned. However it first introduced the idea of "patient point managed per nurse". TISS update was elaborated by Keene in 1983. The therapeutic procedures were increased to 76. It was assumed that a single nurse can manage 40/50 points per day. Though not validated, it became the most used tool to assess complexity of treatment and nurse/patient ratio. However many of these items are obsolete and frequently related to the severity of illness rather than to specific nursing interventions. PRN-Project Research of Nursing was elaborated by EROS during 1980-1987. Points are assigned to each nursing activity according to their frequency, duration, need for more than one nurse, etc. It results quite time consuming, thus unsuitable for routine use. OMEGA elaborated in 1986 describes 86 therapeutic interventions, grouped in 3 categories, measured at the end of ICU stay, thus representing a measure of global workload and use of resources. TOSS-Time Oriented Score System was elaborated by GIRTI in 1991. This score was studied and tested in Italy. It represents a direct temporal evaluation of nursing workload. The score is expressed in minutes. It is reliable and relatively simple, and has been validated on over 2 700 ICU patients. TISS 28 was elaborated by Miranda in 1996. It represents a simplified and updated version of the original TISS, proposed to assess the nursing workload. The authors stated that a nurse can deal with 46 points over the 24 hours. NEMS-Nine Equivalents of nursing Manpower use Score was elaborated by Miranda in 1997. It was derived from TISS and TISS28. Only 9 items, related to specific organ support, nursing and diagnostic/therapeutic interventions inside or outside the ICU, are considered. These items were weighted by multivariate analysis, obtaining a score comparable to the TISS28 score. Each nurse can deal with 45/50 points per day. NAS-Nursing Activity Score was elaborated by Miranda in 2003. It was derived from TISS28, aiming at the description of nursing activities not necessarily correlated to the severity of illness. It describes 81% of the nursing time, compared to 43% of TISS 28. In conclusion, many scoring systems have been proposed to describe nursing workload, both directly (as with TOSS and PRN) or through severity and complexity of treatment (TISS, TISS 28, NAS and NEMS). These scores represent the instruments to assess the correct use of ICU resources.

Early nuclear alterations and immunohistochemical expression of Ki-67, Erb-B2, vascular endothelial growth factor (VEGF), transforming growth factor (TGF-beta1) and integrine-linked kinase (ILK) two days after tamoxifen in breast carcinoma.

The purpose of the present study was to evaluate breast carcinoma samples before and two days after treatment with tamoxifen in order to analyse early histopathological alterations--particularlynuclear alterations-- as well as immunohistochemical expression of Ki-67, Erb-B2, VEGF, TGF-beta1 and ILK proteins. Twenty one cases of invasive ductal and lobular breast carcinoma were studied. Patients were submitted to biopsy of the lesion and, after confirmation of the diagnosis, they received 20 mg of tamoxifen a day, beginning two days before surgery. The samples obtained during biopsy and after surgery were stained with HE for histopathological diagnosis. Estrogen receptor was positive in 18 cases and negative in 3. The immunohistochemical method was applied for the detection of Ki-67, Erb-B2, protein, vascular endothelial growth factor (VEGF), transforming growth factor beta (TGF-beta1) and integrin linked kinase (ILK). Two days after tamoxifen treatment, the following results were observed: 1) decrease in the cell volume, chomatine condensation, nucleoli less evident and clearly defined nuclear limits; 2) significant reduction in the expression of Erb-B2 protein and significant increase in the expression of TGF-beta1 protein; 3) expression of others proteins (Ki-67, VEGF and ILK) was not altered during the indicated time frame. Our results suggest that analyzing nuclear alterations and expression of Erb-B2 and TGF-beta1 proteins would be useful to assess the initial response to tamoxifen.

Age-dependent activin receptor expression pinpoints activin A as a physiological regulator of rat Sertoli cell proliferation.

It is currently believed that the fertility level of the adult mammalian testis is related to the total number of Sertoli cells, which is established in the early prepubertal life. We have previously reported that, in an in-vitro system, terminal Sertoli cell proliferation is sustained by activin A in concert with FSH. In this paper, we have addressed the question of whether this activin A effect correlates with activin receptor II (ActRII) expression pattern during early post-natal testis development. We first determined the precise developmental interval of activin proliferative effect on Sertoli cells in vitro and then analysed the expression of ActRII in purified testicular cell populations by Northern blot and in-situ hybridization. While the 3 kb ActRII isoform was widely expressed at different ages and in several testicular cells, including Sertoli cells, germ cells and myoid cells, the canonical 6 kb ActRII isoform was specifically and transiently expressed at a high rate in Sertoli cells at 7-9 days after birth, the time when these cells respond to activin A in vitro. In the light of these results, we conclude that activin A regulates terminal Sertoli cell proliferation in the rat testis and that this effect is mediated by the 6 kb isoform of ActRII.

Life-threatening adverse events of antiepileptic drugs.

Treating a patient with antiepileptic drugs (AEDs) may give rise to unexpected life-threatening adverse events. Despite extensive experimental and clinical testing to ensure safety, most AEDs on the market have been associated with cases of severe cutaneous reactions, serious hematological disorders, or hepatic failure. Most of these disorders emerge as idiosyncratic immune-mediated disease or are related to toxic metabolic products of the AEDs. Early diagnosis is the only means of reducing the harmful, potentially fatal effects of these reactions. A high degree of suspicion, knowledge of risk factors, and close physician-patient contact increases the likelihood of early diagnosis and treatment. When diagnosed, severe reactions must be fully documented and reported to health authorities. The very rare occurrence of life threatening events should not, in general, limit treatment decision-making. Future epidemiological, chemical, and genetic research might provide methods for ascertaining which patients are at risk, so undue exposure can be avoided.

Cooperative transformation of 32D cells by the combined expression of IRS-1 and V-Ha-Ras.

32D cells expressing v-Ha-Ras fail to show a transformed phenotype. Since Ras requires an active IGF-1R for transformation of fibroblasts, we asked whether expression of IRS-1 or Shc (two of the major substrates of the IGF-1R) could co-operate with oncogenic Ras in transforming 32D cells. We find that IRS-1, but not Shc, in combination with v-Ha-Ras generates a fully transformed phenotype in 32D cells. 32D cells expressing both IRS-1 and v-Ha-Ras (32D/IRS1/Ras) survive and proliferate in the absence of IL-3, do not undergo granulocytic differentiation in the presence of G-CSF and form tumors in nu/nu and syngeneic mice. In contrast, 32D cells expressing singly IRS-1 or v-Ha-Ras exhibit only a block in differentiation capacity. Over-expression of Shc proteins, by itself, promotes differentiation of 32D cells. Concomitant expression of IRS-1 and v-Ha-Ras synergistically phosphorylates ERK-1 and ERK-2 whereas a MEK inhibitor rapidly induces death of 32D/IRS1/Ras transformed cells. Furthermore, transformed 32D/IRS1/Ras cells display high levels of PI3-K activation and undergo rapid apoptosis when exposed to PI3-K inhibitors. The data indicate that: (1) a fully transformed phenotype in 32D cells is generated when a block in differentiation (v-Ha-Ras) is coupled with another differentiation block (IRS-1); (2) PI3-K and MAPK activity are required for the survival of transformed cells; (3) the signals generated by IRS-1 and oncogenic Ras converge on ERK and PI3-K resulting in high levels of activation.

Accuracy of electrocardiogram reading by family practice residents.

OBJECTIVES: This study evaluated the electrocardiogram (EKG) reading skills of family practice residents. METHODS: A multicenter study was carried out to evaluate the accuracy of EKG reading in the family practice setting. Based on the frequency and potential for clinical significance, we chose 18 common findings on 10 EKGs for evaluation. The EKGs were then distributed to residents at six family practice residencies. Residents were given one point for the identification of each correct EKG finding and scored based on the number correct over a total of 18. RESULTS: Sixty-one residents (20 first year, 23 second year, and 18 third year) completed readings for 10 EKGs and were evaluated for their ability to identify 18 EKG findings. The median score out of 18 possible points for all first-, second-, and third-year residents was 12, 12, and 11.5, respectively. Twenty-one percent of residents did not correctly identify a tracing of an acute myocardial infarction. Data analysis showed no statistically significant difference among the three groups of residents. CONCLUSIONS: We evaluated the accuracy of EKG reading skills of family practice residents at each year of training. This study suggests that EKG reading skills do not improve during residency, and further study of curricular change to improve these skills should be considered.

Cyclic expression of endothelin-converting enzyme-1 mediates the functional regulation of seminiferous tubule contraction.

The potent smooth muscle agonist endothelin-1 (ET-1) is involved in the local control of seminiferous tubule contractility, which results in the forward propulsion of tubular fluid and spermatozoa, through its action on peritubular myoid cells. ET-1, known to be produced in the seminiferous epithelium by Sertoli cells, is derived from the inactive intermediate big endothelin-1 (big ET-1) through a specific cleavage operated by the endothelin-converting enzyme (ECE), a membrane-bound metalloprotease with ectoenzymatic activity. The data presented suggest that the timing of seminiferous tubule contractility is controlled locally by the cyclic interplay between different cell types. We have studied the expression of ECE by Sertoli cells and used myoid cell cultures and seminiferous tubule explants to monitor the biological activity of the enzymatic reaction product. Northern blot analysis showed that ECE-1 (and not ECE-2) is specifically expressed in Sertoli cells; competitive enzyme immunoassay of ET production showed that Sertoli cell monolayers are capable of cleaving big ET-1, an activity inhibited by the ECE inhibitor phosphoramidon. Microfluorimetric analysis of intracellular calcium mobilization in single cells showed that myoid cells do not respond to big endothelin, nor to Sertoli cell plain medium, but to the medium conditioned by Sertoli cells in the presence of big ET-1, resulting in cell contraction and desensitization to further ET-1 stimulation; in situ hybridization analysis shows regional differences in ECE expression, suggesting that pulsatile production of endothelin by Sertoli cells (at specific "stages" of the seminiferous epithelium) may regulate the cyclicity of tubular contraction; when viewed in a scanning electron microscope, segments of seminiferous tubules containing the specific stages characterized by high expression of ECE were observed to contract in response to big ET-1, whereas stages with low ECE expression remained virtually unaffected. These data indicate that endothelin-mediated spatiotemporal control of rhythmic tubular contractility might be operated by Sertoli cells through the cyclic expression of ECE-1, which is, in turn, dependent upon the timing of spermatogenesis.

A rapid method of Sertoli cell isolation by DSA lectin, allowing mitotic analyses.

We have developed a rapid and convenient method of Sertoli cell preparation for studying the growth kinetics of these cells in in vitro culture. Datura Stramonium agglutinin (DSA)-coated dishes were used to rapidly purify single Sertoli cells from immature rat testis. We have monitored by immunohistochemical markers the degree of contamination of our Sertoli cell preparation by other cell types. The cell preparation is essentially free of germ cells and interstitial cells and contains a minimal percentage of myoid cells. Sertoli cells isolated with this method retain functional activities such as the FSH responsiveness in terms of cAMP production. In addition, we have studied the proliferative activity of Sertoli cells isolated by lectin binding from rats of different ages. Sertoli cells exhibited a characteristic pattern of proliferation which was a function of the donor animal age. The proliferative activity of isolated Sertoli cells decreased with age, being much higher in 3 day-old rats than in older animals. A similar pattern was observed when the mitotic activity of Sertoli cells in response to mitogens present in the testicular extracts from 5 day-old rats was evaluated. The method described here reduces or eliminates many of the drawbacks of the conventional procedures used to isolate Sertoli cells, thus providing a useful tool in studies of growth kinetics and regulation of cell proliferation in vitro.