Modified transseptal approach in endoscopic transsphenoidal pituitary surgery

OBJECTIVE

Transsphenoidal pituitary surgery is commonly performed via a direct transostial approach with a posterior septectomy. However, a technique via an endoscopic transseptal route has been described that avoids a posterior septectomy, but it comes with its own disadvantages.

METHODS

This paper describes a modification, and discusses its pros and cons.

RESULTS

The initial incision in the mucosa is placed level with the anterior middle turbinate. The mucoperichondrial flap is raised ipsilaterally until the sphenoid sinus ostium. An incision is made at the osseocartilaginous junction, and the contralateral mucoperichondrial flap is raised. The bony septum and posterior aspect of this flap is excised. The size and position of this window can be adapted. At the end of the operation, the lateralised intact mucoperichondrial flap is moved back to the midline.

CONCLUSION

Excision or deflection of the cartilaginous septum is not required. It maintains an intact septal mucosa on one side and avoids a septal perforation.

P-407 Pregnancy outcomes of different endometrial preparation in patients with a history of cesarean section

Study question

To investigate the efficacies of three cycle regimens in women receiving frozen embryo transfer with a history of cesarean section(CS).

Summary answer

In women undergoing frozen embryo transfer with a history of CS, hormone replacement therapy for endometrial preparation was associated with a higher early miscarriage rate.

What is known already

Rates of CS are rising worldwide. Many women with a history of a CS delivery conceived through assisted reproductive technology (ART) are in need of frozen embryo transfer (FET) for their second progeny. Various protocols for endometrium preparation have been used to provide an optimal uterine environment for the transfer of thawed embryos, but the evidence supporting the superiority of one protocol over another is insufficient.

Study design, size, duration

A retrospective cohort study of patients (N = 6,159) with a history of CS who fulfilled the inclusion criteria were enrolled in the study from January 2014 to December 2019 at the CITIC-Xiangya Hospital of Reproduction and Genetics.

Participants/materials, setting, methods

Reproductive outcomes of patients in the natural cycle （NC） (n = 4,306) versus hormone replacement therapy（HRT） (n = 1,007) versus gonadotropin-releasing hormone agonist （GnRH-a） + HRT groups (n = 846) were compared. Multiple logistic regression analyses were performed to investigate the potential confounding factors.

Main results and the role of chance

The unadjusted odds of the miscarriage rate of singleton pregnancies were also significantly higher in the hormone replacement therapy compared with the natural cycle (25.5% versus 20.4%, respectively). After adjusting for possible confounding factors, the early miscarriage rate and the miscarriage rate of singleton pregnancies remained significantly higher in the hormone replacement therapy than the natural cycle. The clinical pregnancy rates in the hormone replacement therapy, hormone replacement therapy and treatment with gonadotropin-releasing hormone agonist of women with a history of cesarean section was 48.8%, 48% and 47.1%, respectively, and the live birth rates were 37%, 34.1% and 35.7%, respectively.

Limitations, reasons for caution

This study is limited by its retrospective design. Furthermore, the detailed ultrasound information on uterine myometrial defects, complications related to CS and the number of previous CSs were unavailable in our study. Another limitation is that pregnancy-related complications and neonatal outcomes were not analyzed.

Wider implications of the findings

Our study could help physicians improve their understanding of the impact of different protocols on pregnancy outcomes in patients with a history of CS. Prospective randomized trials should be conducted to assess the efficacy of endometrial preparation protocols for FET in women with a history of CS.

Trial registration number

not applicable

Unveiling the interaction mechanism of alogliptin benzoate with human serum albumin: Insights from spectroscopy, microcalorimetry, and molecular docking and molecular dynamics analyses

The interaction between a DPP-4 inhibitor, alogliptin benzoate (AB), and human serum albumin (HSA) was systematically investigated via spectroscopy, microcalorimetry and molecular simulations. Steady-state fluorescence and time-resolved fluorescence spectrometry illustrated that the fluorescence quenching type of AB to HSA was static and caused by the formation of ground state AB-HSA complex. Isothermal titration calorimetry (ITC) combined with fluorescence spectra revealed that the affinity of AB to the subdomain IIA of HSA was moderate with a binding constant in the order of 10⁴. Molecular docking analysis and thermodynamic parameters demonstrated that this combination was maintained by hydrogen bonding along with van der Waals force and hydrophobic force. Circular dichroism and three-dimensional (3D) fluorescence showed that AB increased the hydrophobicity of Trp residue and the α-helix content of HSA by 1.99%. Microdifferential scanning calorimetry revealed that the addition of AB enhanced the thermal stability of HSA. The action forces, binding stability, binding sites, and protein structure of the AB-HSA system were evaluated via molecular dynamics analysis in the simulated environment. On the basis of molecular docking, MD simulation constructed a more reliable 3D model of the AB-HSA complex in terms of spatial structure.

Study on the interaction of ertugliflozin with human serum albumin in vitro by multispectroscopic methods, molecular docking, and molecular dynamics simulation

Ertugliflozin is a potent and selective inhibitor of sodium-dependent glucose cotransporters 2 (SGLT2) and used as a monotherapy to improve glycemic control in adult patients with type 2 diabetes. In this study, ertugliflozin binding to human serum albumin (HSA) was investigated by multispectroscopic and computer simulations. The fluorescence spectra demonstrated that the quenching mechanism of ertugliflozin and HSA was static quenching. Thermodynamic parameters indicated that hydrogen bonding and van der Waals forces played a key role in the binding. Fluorescence competition experiments and molecular docking revealed that ertugliflozin bound to HSA sites II. In three-dimensional fluorescence, circular dichroism spectroscopy, and molecular dynamics simulation, ertugliflozin did not affect the basic skeleton structure of HSA but slightly increased the α-helical structure content and changed the microenvironment around amino acid residues. Results provide valuable information on the basis of the interaction of ertugliflozin with HSA.

Binding behavior of trelagliptin and human serum albumin: Molecular docking, dynamical simulation, and multi-spectroscopy

This study aims to investigate the interaction mechanism of a hypoglycemic agent, trelagliptin (TLP), and human serum albumin (HSA) through computer simulation and assisted spectroscopy methods. Computer simulation including molecular docking and molecular dynamics analysis was conducted under physiological conditions. Molecular docking results indicate that TLP bound to HSA at site I, and the binding behavior was mainly governed by hydrophobic force. Competitive experiments further verified the theoretical conclusion from molecular docking. Molecular dynamics simulation revealed that TLP indeed stably bound to site I of HSA in the hydrophobic subdomain IIA. Moreover, TLP presented a certain effect on the structural compactness of HSA. In molecular dynamics simulation, hydrogen bonds appeared, which suggested the reliability and stability of the combination. The binding energy of the stable phase is around -250 kJ/mol. Fluorescence quenching studies and time-resolved fluorescence analysis indicated that the evident fluorescence quenching phenomenon of HSA could be due to TLP binding initiated by static quenching mechanism. The binding constants (K_a) of the complex were found to be around 10⁴ via fluorescence data, and the calculated thermodynamic parameters indicated that hydrophobic force played major role in the binding of TLP to HSA. Synchronous fluorescence and three-dimensional fluorescence results demonstrated that TLP slightly disturbed the microenvironment of amino residues. Circular dichroism spectra showed that TLP affected the secondary structure of HSA. The theoretical and experimental results showed excellent agreement.

Interaction mechanism of olaparib binding to human serum albumin investigated with NMR relaxation data and computational methods

The interaction mechanism between olaparib (OLA) and human serum albumin (HSA) has been investigated using experimental and computational techniques. An NMR relaxation approach based on the analysis of proton selective and non-selective spin-lattice relaxation rates at different temperatures can provide quantitative information about the affinity index and the thermodynamic equilibrium constant of the OLA-HSA system. The affinity index and the thermodynamic equilibrium constant decreased as temperature increased, indicating that the interactions between OLA and HSA could be weakened as temperature increased. Molecular docking and dynamics simulations revealed that OLA stably bound to subdomain II (site 1), and OLA could induce the conformational and micro-environmental changes in HSA. CD results suggested that α-helix content decreased after OLA was added, demonstrating that OLA affected the secondary structure of HSA.

Mesalazine/hydroxypropyl-β-cyclodextrin/chitosan nanoparticles with sustained release and enhanced anti-inflammation activity

This study aimed to develop a novel sustained release system for mesalazine (MSZ) by preparing hydroxypropyl-β-cyclodextrin (HP-β-CD) inclusion complex loaded chitosan (CS) nanoparticles (NPs). The HP-β-CD/MSZ complex was prepared at 1:1 stoichiometry and characterized by using various analysis techniques. The HP-β-CD/MSZ/CS NPs prepared under the optimum condition had a spherical shape (90±17 nm diameter), a narrow size distribution, and a high loading efficiency. Compared with free MSZ, the HP-β-CD/MSZ/CS NPs exhibited an obvious sustained release of MSZ. The activity of the NPs against a cytokine-triggered inflammatory response was evaluated in cytokine-stimulated HT-29 cell lines by monitoring key inflammatory mediators. The results revealed that compared with free MSZ, the NPs more strongly inhibited the production of NO, PGE₂, and IL-8, indicating the NPs possibly had better anti-inflammatory effects. Therefore, the established HP-β-CD/MSZ/CS NPs may be a promising delivery system of MSZ.

Studies of the binding properties of the food preservative thiabendazole to DNA by computer simulations and NMR relaxation

Thiabendazole (TBZ) is a commonly used food preservative and has a wide range of anthelmintic properties. In this study, computer simulations and experiments were conducted to investigate the interaction mechanism of TBZ and herring sperm DNA (hsDNA) at the molecular level. Molecular docking showed that TBZ interacted with DNA in groove mode and bound in A-T and C-G base pair regions. Molecular dynamics (MD) was used to evaluate the stability of the TBZ–DNA complex and found that the three phases in MD and the hydrogen bonds helped maintain the combination. NMR relaxation indicated that TBZ had a certain affinity to hsDNA with a binding constant of 462.43 L mol⁻¹, and the thiazole ring was the main group bound with DNA. Results obtained from fluorescence experiments showed that the binding of TBZ and hsDNA was predominantly driven by enthalpy through a static quenching mechanism. Circular dichroism and viscosity measurements proved the groove binding mode. The FTIR results clarified the conformational changes of DNA, that the DNA helix became shorter and compact, and the DNA structure transformed from B-form to A-form.

The groove binding of thiabendazole and hsDNA was studied by computer simulation and experimental methods.

Capecitabine as a minor groove binder of DNA: molecular docking, molecular dynamics, and multi-spectroscopic studies

The interaction mechanism and binding mode of capecitabine with ctDNA was extensively investigated using docking and molecular dynamics simulations, fluorescence and circular dichroism (CD) spectroscopy, DNA thermal denaturation studies, and viscosity measurements. The possible binding mode and acting forces on the combination between capecitabine and DNA had been predicted through molecular simulation. Results indicated that capecitabine could relatively locate stably in the G-C base-pairs-rich DNA minor groove by hydrogen bond and several weaker nonbonding forces. Fluorescence spectroscopy and fluorescence lifetime measurements confirmed that the quenching was static caused by ground state complex formation. This phenomenon indicated the formation of a complex between capecitabine and ctDNA. Fluorescence data showed that the binding constants of the complex were approximately 2 × 10⁴ M^-1. Calculated thermodynamic parameters suggested that hydrogen bond was the main force during binding, which were consistent with theoretical results. Moreover, CD spectroscopy, DNA melting studies, and viscosity measurements corroborated a groove binding mode of capecitabine with ctDNA. This binding had no effect on B-DNA conformation.

Combined spectroscopy methods and molecular simulations for the binding properties of trametinib to human serum albumin

Trametinib is a novel anticancer drug for treating metastatic cutaneous melanoma. The present study probed into the binding of trametinib to human serum albumin (HSA) through spectroscopy methods and molecular simulations. Trametinib could quench the fluorescence of HSA through static quenching which could be probed via fluorescence spectroscopy and time-resolved fluorescence. Thermodynamic parameters and docking results indicated that hydrogen bonds and van der Waals forces play crucial roles in this binding process, which exerts almost no effect on the HSA conformation under synchronous fluorescence, three-dimensional fluorescence, circular dichroism spectra, and molecular dynamics simulations. Site marker displacement experiments and molecular docking reveal that trametinib primarily binds to Sudlow site I of HSA. In addition, the trametinib–HSA interaction was hardly influenced by varying amino acid (glutamine, alanine, glycine, and valine) concentrations. This study can provide useful information for the pharmacokinetic properties of trametinib.

Probing the binding properties of trametinib to human serum albumin.

Interactions between the antiviral drug telaprevir and human serum albumin: a combined study with spectroscopic methods and molecular modeling

The binding mechanism between telaprevir and human serum albumin was explored by combining spectroscopic methods and molecular dynamics simulations.

A rare PAX6 mutation in a Chinese family with congenital aniridia

Aniridia is an autosomal dominant disorder characterized by the complete or partial loss of the iris and is almost associated with mutations in the paired box gene 6 (PAX6). We examined three generations of a Chinese family with congenital aniridia and observed genetic defects. Exons of PAX6 from 12 family members were amplified by polymerase chain reaction, sequenced, and compared with reference sequences in NCBI reference sequence database (http://www.ncbi.nlm.nih.gov/nuccore/NG_008679.1?from=5001&to=38170&report=genbank). A rare mutation c.2T>A (M1K) in exon 4 of PAX6 was identified in all affected family members but not in unaffected family members. Our results suggest that the c.2T>A (M1K) mutation may be responsible for the pathogenesis of congenital aniridia in this family. To our knowledge, this is the first report of the M1K mutation in PAX6 in a Chinese family with this disease and the second report worldwide.

A novel mutation of PAX6 identified in a Chinese twin family with congenital aniridia complicated with nystagmus

Genetic variations within the paired box gene 6 (PAX6) gene are associated with congenital aniridia. To detect the genetic defects in a Chinese twin family with congenital aniridia and nystagmus, exons of PAX6 were amplified by polymerase chain reaction (PCR), sequenced and compared with a reference database. Six members from the family of three generations were included in the study. The twins' father presented with congenital aniridia, nystagmus and cataract at birth, while the twins presented with congenital aniridia and nystagmus. A novel mutation c.888 insA in exon 10 of PAX6 was identified in all affected individuals. This study suggests that the novel mutation c.888 insA is likely responsible for the pathogenesis of the congenital aniridia and nystagmus in this pedigree. To the best of our knowledge, this is the first report of this mutation in PAX6 gene in pedigree with aniridia. Furthermore, no PAX6 gene defect was reported in twins with congenital aniridia.

Downregulation of miR-221/222 enhances sensitivity of breast cancer cells to tamoxifen through upregulation of TIMP3

Aberrantly expressed microRNAs (miRNAs) are involved in breast tumorigenesis. It is still unclear if and how miRNAs-221/222 are implicated in breast cancer and the resistance to estrogen receptor modulator tamoxifen. We investigated the roles and mechanisms of miR-221/222 in breast cancer cells, particularly in modulating response to tamoxifen therapy. MCF-7 and MDA-MB-231 breast cancer cells were transfected with antisense oligonucleotides AS-miR-221 and AS-miR-222 and their expression of miR-221 and miR-222 was assessed. The correlation of miR-221/222 with tissue inhibitor of metalloproteinase-3 (TIMP3) expression was investigated by fluorescence quantitative PCR and western blotting analysis. The therapeutic sensitivity of these cells, transfected and untransfected, to tamoxifen was determined. Transfection of AS-miR-221 and AS-miR-222 dramatically inhibited expression of miR-221 and miR-222, respectively, in both MCF-7 and MDA-MB-231 cells (P<0.05-0.01). Downregulation of miR-221/222 significantly increased the expression of TIMP3 compared with controls (P<0.05-0.01). The viability of estrogen receptor (ER)-positive MCF-7 cells transfected with AS-miR-221 or/and AS-miR-222 was significantly reduced by tamoxifen (P<0.05-0.01). We have demonstrated for the first time that suppression of miRNA-221/222 increases the sensitivity of ER-positive MCF-7 breast cancer cells to tamoxifen. This effect is mediated through upregulation of TIMP3. These findings suggest that upregulation of TIMP3 via inhibition of miRNA-221/222 could be a promising therapeutic approach for breast cancer.

Secretion expression of recombinant glucagon inEscherichia coli

A novel approach for the preparation of recombinant human glucagon was described. An expression vector pAGluT, containing phoA promoter, phoA signal peptide and glucagon gene, was constructed by means of genetic engineering.Escherichia coli strain YK537 was transformed with pAGluT. High-level secretory expression of recombinant human glucagon was achieved. The expression yield of recombinant human glucagon was found to be 80 mg/L, approximately 30% of the total proteins in supernatant. The biological activities and the physicochemical properties of the purified recombinant human glucagon were found to be the same as that of native glucagon. In addition, our results suggested that phoA expression system may be suitable for the expression of other small peptides.

Rifampicin and sodium fusidate reduces the frequency of methicillin-resistant Staphylococcus aureus (MRSA) isolation in adults with cystic fibrosis and chronic MRSA infection

Nosocomial transmission of methicillin-resistant Staphylococcus aureus (MRSA) to patients with cystic fibrosis (CF) frequently results in chronic respiratory tract carriage. This is an increasing problem, adds to the burden of glycopeptide antibiotic use in hospitals, and represents a relative contraindication to lung transplantation. The aim of this study was to determine whether it is possible to eradicate MRSA with prolonged oral combination antibiotics, and whether this treatment is associated with improved clinical status. Adult CF patients (six male, one female) with chronic MRSA infection were treated for six months with rifampicin and sodium fusidate. Outcome data were examined for six months before treatment, on treatment and after treatment. The patients had a mean age of 29.3 (standard deviation=6.3) years and FEV(1) of 36.1% (standard deviation=12.7) predicted. The mean duration of MRSA isolation was 31 months. MRSA isolates identified in these patients was of the same lineage as the known endemic strain at the hospital when assessed by pulsed-field gel electrophoresis. Five of the seven had no evidence of MRSA during and for at least six months after rifampicin and sodium fusidate. The proportion of sputum samples positive for MRSA was lower during the six months of treatment (0.13) and after treatment (0.19) compared with before treatment (0.85) (P<0.0001). There was a reduction in the number of days of intravenous antibiotics per six months with 20.3+/-17.6 on treatment compared with 50.7 before treatment and 33.0 after treatment (P=0.02). There was no change in lung function. Gastrointestinal side effects occurred in three, but led to therapy cessation in only one patient. Despite the use of antibiotics with anti-staphylococcal activity for treatment of respiratory exacerbation, MRSA infection persists. MRSA can be eradicated from the sputum of patients with CF and chronic MRSA carriage by using rifampicin and sodium fusidate for six months. This finding was associated with a significant reduction in the duration of intravenous antibiotic treatment during therapy.

Multiple co-infections (Mycoplasma, Chlamydia, human herpes virus-6) in blood of chronic fatigue syndrome patients: association with signs and symptoms

Previously we and others found that a majority of chronic fatigue syndrome (CFS) patients showed evidence of systemic mycoplasmal infections, and their blood tested positive using a polymerase chain reaction assay for at least one of the four following Mycoplasma species: M. fermentans, M. hominis, M. pneumoniae or M. penetrans. Consistent with previous results, patients in the current study (n=200) showed a high prevalence (overall 52%) of mycoplasmal infections. Using forensic polymerase chain reaction we also examined whether these same patients showed evidence of infections with Chlamydia pneumoniae (overall 7.5% positive) and/or active human herpes virus-6 (HHV-6, overall 30.5% positive). Since the presence of one or more infections may predispose patients to other infections, we examined the prevalence of C. pneumoniae and HHV-6 active infections in mycoplasma-positive and -negative patients. Unexpectedly, we found that the incidence of C. pneumoniae or HHV-6 was similar in Mycoplasma-positive and -negative patients, and the converse was also found in active HHV-6-positive and -negative patients. Control subjects (n=100) had low rates of mycoplasmal (6%), active HHV-6 (9%) or chlamydial (1%) infections, and there were no co-infections in control subjects. Differences in bacterial and/or viral infections in CFS patients compared to control subjects were significant. Severity and incidence of patients' signs and symptoms were compared within the above groups. Although there was a tendency for patients with multiple infections to have more severe signs and symptoms (p<0.01), the only significant differences found were in the incidence and severity of certain signs and symptoms in patients with multiple co-infections of any type compared to the other groups (p<0.01). There was no correlation between the type of co-infection and severity of signs and symptoms. The results indicate that a large subset of CFS patients show evidence of bacterial and/or viral infection(s), and these infections may contribute to the severity of signs and symptoms found in these patients.

Patent foramen ovale size and embolic brain imaging findings among patients with ischemic stroke

BACKGROUND AND PURPOSE

Although the cause of stroke among patients with patent foramen ovale (PFO) may be due to paradoxical cerebral embolism (PCE), this mechanism is often difficult to prove. The aim of our study was to evaluate the association between brain imaging findings suggestive of embolism and PFO among ischemic stroke patients.

METHODS

As part of the Northern Manhattan Stroke Study, 95 patients with first ischemic stroke over age 39 underwent transesophageal echocardiography (TEE) for evaluation of a cardiac source of embolism. The stroke subtype was determined by modified NINDS Stroke Data Bank criteria. Stroke subtype and MRI/CT imaging data were evaluated blind to the presence of a PFO. These findings were compared between two groups: patients with medium to large PFO (> or =2 mm) and small (<2 mm) or no PFO.

RESULTS

Of the 95 patients who underwent TEE, 31 (33%) had a PFO. The frequency of PFO was significantly greater among patients with cryptogenic infarcts (19 of 42; 45%) compared with patients with determined cause of stroke (12 of 53, 23%; P=0.02). Medium to large PFOs were found more often among cryptogenic strokes than among infarcts of determined cause (26% versus 6%; P=0.04). Superficial infarcts occurred more often in the group with larger PFOs than in the group with small or no PFOs (50% versus 21%; P=0.02). Patients with medium or large PFOs more frequently had occipital and infratentorial strokes (57% versus 27%; P=0.02).

CONCLUSIONS

Stroke patients with larger PFOs show more brain imaging features of embolic infarcts than those with small PFOs. Larger PFOs may be more likely to cause paradoxical embolization and may help explain the stroke mechanism among patients with no other definite cause.

Stroke incidence among white, black, and Hispanic residents of an urban community: the Northern Manhattan Stroke Study

Stroke mortality is reported to be greater in blacks than in whites, but stroke incidence data for blacks and Hispanics are sparse. The aim of this study was to determine and compare stroke incidence rates among whites, blacks, and Hispanics living in the same urban community. A population-based incidence study was conducted to identify all cases of first stroke occurring in northern Manhattan, New York City, between July 1, 1993, and June 30, 1996. The population of this area was approximately 210,000 at that time, based on 1990 US Census data. Surveillance for hospitalized and nonhospitalized stroke consisted of daily screening of all admissions, discharges, and computed tomography logs at Columbia-Presbyterian Medical Center, the only hospital in the region, and review of discharge lists from outside hospitals, telephone surveys of random households, and contacts with community physicians, Visiting Nurses' Services, and community agencies. Stroke incidence increased with age and was greater in men than in women. The average annual age-adjusted stroke incidence rate at age > or =20 years, per 100,000 population, was 223 for blacks, 196 for Hispanics, and 93 for whites. Blacks had a 2.4-fold and Hispanics a twofold increase in stroke incidence compared with whites. Cerebral infarct accounted for 77 percent of all strokes, intracerebral hemorrhage for 17 percent, and subarachnoid hemorrhage for 6 percent. These data from the Northern Manhattan Stroke Study suggest that part of the reported excess stroke mortality among blacks in the United States may be a reflection of racial/ethnic differences in stroke incidence.

Leisure-time physical activity and ischemic stroke risk: the Northern Manhattan Stroke Study

BACKGROUND AND PURPOSE

Physical activity reduces the risk of premature death and cardiovascular disease, but the relationship to stroke is less well studied. The objective of this study was to investigate the association between leisure-time physical activity and ischemic stroke in an urban, elderly, multiethnic population.

METHODS

The Northern Manhattan Stroke Study is a population-based incidence and case-control study. Case subjects had first ischemic stroke, and control subjects were derived through random-digit dialing with 1:2 matching for age, sex, and race/ethnicity. Physical activity was recorded through a standardized in-person interview regarding the frequency and duration of 14 activities over the 2 prior weeks. Conditional logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals after adjustment for medical and socioeconomic confounders.

RESULTS

Over 30 months, 369 case subjects and 678 control subjects were enrolled. Mean age was 69.9 +/- 12 years; 57% were women, 18% whites, 30% blacks, and 52% Hispanics. Leisure-time physical activity was significantly protective for stroke after adjustment for cardiac disease, peripheral vascular disease, hypertension, diabetes, smoking, alcohol use, obesity, medical reasons for limited activity, education, and season of enrollment (OR = 0.37; 95% confidence interval=0.25 to 0.55). The protective effect of physical activity was detected in both younger and older groups, in men and women, and in whites, blacks, and Hispanics. A dose-response relationship was shown for both intensity (light-moderate activity OR = 0.39; heavy OR = 0.23) and duration (<2 h/wk OR = 0.42; 2 to <5 h/wk OR = 0.35; > or =5 h/wk OR = 0.31) of physical activity.

CONCLUSIONS

Leisure-time physical activity was related to a decreased occurrence of ischemic stroke in our elderly, multiethnic, urban subjects. More emphasis on physical activity in stroke prevention campaigns is needed among the elderly.

Testing the validity of the lacunar hypothesis: the Northern Manhattan Stroke Study experience

BACKGROUND/OBJECTIVE

Few studies have attempted to validate the "lacunar hypothesis." The accuracy of identifying lacunar and other nonlacunar mechanisms of infarction will be increasingly important in evaluating potential stroke treatments. The aim of this study was to determine the value of lacunar syndromes in predicting radiologic lacunes and the value of clinicoradiologic lacunes in predicting "lacunar infarction" as final stroke mechanism.

METHODS

From 1990 to 1994, 591 patients with cerebral infarction, who were from northern Manhattan and over the age of 39, were prospectively examined. Data were collected on the admitting clinical syndrome (lacunar or nonlacunar) and brain imaging findings. Lacunar syndromes were categorized as pure motor hemiparesis (PMH), pure sensory syndrome (PSS), sensorimotor syndrome (SMS), ataxic-hemiparesis (A-H), and other lacunar syndromes. Brain imaging findings were classified as radiologic lacune or nonlacune. Positive predictive values, sensitivities, and specificities of lacunar syndromes for identifying radiologic lacunes were calculated. The final mechanism of infarction was determined after review of all the diagnostic tests and compared among the lacunar groups.

RESULTS

Lacunar syndromes occurred in 225 cases. PMH was the most common lacunar syndrome, accounting for 45%, SMS 20%, A-H 18%, and PSS 7%. Lacunar syndromes had an overall positive predictive value (PPV) of 87% for detecting radiologic lacune: PSS 100%, A-H 95%, SMS 87%, and PMH 79%. Among the 195 patients who presented with a lacunar syndrome and had this condition confirmed radiologically, 147 were classified as having a final diagnosis of lacunar mechanism of infarction (PPV = 75%). Atherosclerosis accounted for 17 (9%), cardioembolism 10 (5%), cryptogenic 17 (9%), and other unusual causes 4 (2%).

CONCLUSION

While lacunar syndromes, especially PSS and A-H, are highly predictive of lacune, in about one in four patients presenting with lacunar syndromes confirmed radiologically the condition is associated with nonlacunar mechanisms of infarction. Noninvasive neurovascular and cardiac evaluations are still warranted even among patients with lacunes.

A new immune escape mutant of hepatitis B virus with an Asp to Ala substitution in aa144 of the envelope major protein

A new hepatitis B virus (HBV) mutant with an Asp to Ala substitution in aa144 of the envelope major protein was identified from the blood samples of two persistently infected patients. They were born to HBsAg-positive carrier mothers. The patients had been immunized with HBV vaccine after birth, under a standard schedule of 3 injections at 0, 1 and 6 months, but failed to be protected. The mutant was stable and was present in the blood samples collected at 1 and 4 years of age from patient 105. To study the antigenic differences, two expression plasmids, pExpW (wild type) and pExpM (mutant), were constructed, and HBsAgs were expressed in COS-M6 cells. The binding activities of the HBsAg from pExpW and pExpM were compared with anti-a-epitope monoclonal antibody and with anti-HBs polyclonal antibody, respectively, by radioimmunoassay. The results showed that the binding activity of HBsAg of pExpM was distinctly lower than that of pExpW, and the HBV mutant with envelope major protein144Asp-->Ala was shown to be a new immune escape variant.

The medullary vascular syndromes revisited

There are two major vascular syndromes of the medulla oblongata: the medial and the lateral. The medial medullary syndrome is characterized by the triad of ipsilateral hypoglossal nerve palsy with contralateral hemiparesis and loss of deep sensation. Lateral medullary infarction commonly presents with Horner's syndrome, ataxia, alternating thermoanalgesia, nystagmus, vertigo and hoarseness. Combinations of the two major syndromes occur as bilateral medial medullary, hemimedullary and bilateral lateral medullary syndromes. Each of these syndromes frequently manifests with incomplete or atypical findings depending on the extent of the lesion. Magnetic resonance imaging has been useful in the clinical diagnosis of medullary infarctions. The site of the lesion may help predict the arteries involved.

The spectrum of concentric macro EMG correlations. Part II. Patients with diseases of muscle and nerve

In the second part of this study we investigate the correlations between the concentric and conmac action potentials in motor units of individuals with diseases of muscle and nerve. We studied 86 myopathic and 86 neurogenic motor units and compared their concentric and conmac action potentials. In the patients with myopathy, we found that the concentric motor unit action potential's (MUAP) area correlates strongly with the conmac potential, even better than in normals, while its amplitude correlates less. In the neurogenic group, we found that both the concentric MUAP's area and amplitude correlated very well with their conmac counterpart, more so than in normals. Thus, in pathology, as in normals, measuring the concentric MUAP's area in addition to its amplitude adds to the diagnostic sensitivity of motor unit potential measurements. These findings are discussed in light of the known dynamic and architectural motor unit changes which take place in the myopathic and neurogenic motor unit.

The cecropin locus. Cloning and expression of a gene cluster encoding three antibacterial peptides in Hyalophora cecropia

Cecropins A, B, and D are antibacterial peptides of 35-37 amino acids that are synthesized in pupae of the Cecropia moth (Hyalophora cecropia) as a response to a bacterial infection. cDNA cloning has shown that the cecropins are made as preproproteins that are processed in four steps to the mature peptides. We have now cloned the genes for preprocecropins A and D, data that together with earlier work on the B gene has made it possible to deduce the arrangement of the cecropin locus. The genes for the three cecropins are organized in a large cluster spanning 20 kilobases of DNA and for each gene there is one copy/haploid genome. The size of the cluster is in part due to long distances between the genes and to the presence of insertion elements in the introns of the A and D genes. The cecropin genes are not expressed in parallel. Transcripts for cecropins A and B appear within 2 h after injection of live bacteria, they reach a maximum after 48 h, and they are continuously expressed at this level for several days. The D gene has a delayed pattern of expression where transcripts appear within 48-96 h and reach a maximum after 144 h. In consonance is also the production of the mature cecropins A, B, and D where the active cecropins A and B are detected in the hemolymph within 10-24 h while the D form is not detected until 48 h post infection. Control injections with sterile saline produced only a weak induction of the cecropin genes.

Immunocytochemical localization of benzo(a)pyrene-DNA adducts in human tissue

Specimens of human lung, uterine cervix, ovary, and placenta were studied for the presence of benzo(a)pyrene 7,8-diol 9,10 epoxide (BPDE)-DNA adducts by using rabbit anti-BPDE-DNA antibody and light microscopic immunocytochemistry. BPDE-DNA antigenicity was detected in the bronchial epithelial cells, cervical epithelium, oocytes, luteal cells, corpora albicans, and hyalinized media of arteries within the ovaries and trophoblastic cells of the placental villi. In conjunction with immunoassay detection of BPDE-DNA adducts in human peripheral blood lymphocytes, this study demonstrates that a variety of human tissues can metabolize and bind the ubiquitous carcinogen benzo(a)pyrene. The identification and localization of this carcinogen-DNA antigenicity in various tissues and cells may not only help in monitoring exposed persons but also give insight to organ site carcinogenesis, transplacental carcinogenesis, and teratogenesis.

The structure of the gene for cecropin B, an antibacterial immune protein from Hyalophora cecropia

Pupae of the moth Hyalophora cecropia respond to an injection of live bacteria by the production of a potent antibacterial activity. The broad-spectrum property of this activity is due chiefly to two small proteins, cecropins A and B. Sequences of the proteins showed them to be homologous and to contain 37 and 35 amino acid residues respectively. The subsequent isolation of two cDNA clones for cecropin B showed that this protein is made as a prepro molecule composed of 62 amino acid residues. We have now prepared a genomic bank and studied four genomic clones for cecropin B. The coding regions were found in two neighbouring BglII fragments, one 0.79 kb and another varying in size from 3.1 kb to 4.9 kb for different clones. One transcriptional unit for preprocecropin B was sequenced and found to be 1035 bp long with a single intron, 514 bp in size. A conserved, insect specific cap site, ATCATTC, was identified by S1 mapping and primer extension experiments. Indications were found for the presence of multigene families and multicopy genes.

Casualty X-ray reporting: a student survey

The radiographs of 337 patients attending the casualty department of a large teaching hospital were reviewed by two medical students of different seniority, a radiology registrar and a consultant radiologist. All the films had been examined initially by the casualty officer when the patient attended. The senior medical student reported the films more reliably than the junior student and was only slightly less reliable than the casualty officer. The radiology registrar was more accurate than the casualty officer where both reports could be compared with the consultant's opinion. Only rarely did the consultant radiologist disagree with the radiology registrar but in one patient this led to a change in management. The need for a radiological opinion has been confirmed.

Analysis of the Mechanism of Gram Differentiation by Use of a Filter-Paper Chromatographic Technique

Bartholomew , J. W. (University of Southern California, Los Angeles), Thomas Cromwell, and Richard Gan . Analysis of the mechanism of Gram differentiation by use of a filter-paper chromatographic technique. J. Bacteriol. 90: 766–777. 1965.—Data are presented which demonstrate that the mechanism of gram-positivity could not be due solely to factors such as a single, specific gram-positive substrate, specific affinities of crystal violet for certain cellular components, a specific crystal violet-iodine-substrate complex, or to any specific characteristic of the dye, iodine, or solvent molecules. Ruptured cells of gram-positive organisms stain gram-negatively when subjected to a standard Gram-stain procedure. However, when stained fragments of broken cells were deposited in thick layers on the surface of filter-paper strips and exposed to decolorizers, the rate of dye release correlated with the Gram characteristic of the intact cell. Therefore, the intact cell in itself is not an absolute requirement for Gram differentiation. The data are interpreted as indicating that the mechanism of Gram differentiation primarily involves the rate of permeation of molecules (dye, iodine, solvent) through the interstitial spaces of cell-wall material.