Development of ISB 1442, a CD38 and CD47 bispecific biparatopic antibody innate cell modulator for the treatment of multiple myeloma

Antibody engineering can tailor the design and activities of therapeutic antibodies for better efficiency or other advantageous clinical properties. Here we report the development of ISB 1442, a fully human bispecific antibody designed to re-establish synthetic immunity in CD38+ hematological malignancies. ISB 1442 consists of two anti-CD38 arms targeting two distinct epitopes that preferentially drive binding to tumor cells and enable avidity-induced blocking of proximal CD47 receptors on the same cell while preventing on-target off-tumor binding on healthy cells. The Fc portion of ISB 1442 is engineered to enhance complement dependent cytotoxicity, antibody dependent cell cytotoxicity and antibody dependent cell phagocytosis. ISB 1442 thus represents a CD47-BsAb combining biparatopic targeting of a tumor associated antigen with engineered enhancement of antibody effector function to overcome potential resistance mechanisms that hamper treatment of myeloma with monospecific anti-CD38 antibodies. ISB 1442 is currently in a Phase I clinical trial in relapsed refractory multiple myeloma.

Effects of 3D Airway Geometry on the Airflow of Adults with Cleft Lip and Palate and Obstructive Sleep Apnea: A Functional Imaging Study

Objective  Individuals with cleft lip and palate (CLP) are at a high risk of developing obstructive sleep apnea (OSA). Hypothetically, the severity of OSA might be associated with the morphology of the upper airway (UAW) and the characteristics of the airflow. Thus, the present study aimed to assess and compare, in adults with CLP and skeletal class-III discrepancy, with or without OSA, simulations of airflow resistance and pressure according to the geometrical characteristics of the UAW and cephalometric parameters. Materials and Methods  According to the results of type-I polysomnography tests, the sample ( n  = 21) was allocated in 2 groups: 1) without OSA (N-OSA; n  = 6); and 2) with OSA (OSA; n  = 15). Cephalometric measurements were performed on the cone-beam computed tomography (CBCT) scans of the groups. After three-dimensional (3D) reconstructions, the volume (V) and minimal cross-sectional area (mCSA) of the UAW were generated. Computational fluid dynamics (CFD) simulations were used to assess key airflow characteristics. The results were presented at a significance level of 5%. Results  The UAW pressure values and airway resistance did not differ between the groups, but there was a tendency for more negative pressures (26%) and greater resistance (19%) in the OSA group. Volume and mCSA showed a moderate negative correlation with resistance and pressure. The more inferior the hyoid bone, the more negative the pressures generated on the pharyngeal walls. Conclusion  The position of the hyoid bone and the geometry of the UAW (V and mCSA) exerted effects on the airway-airflow resistance and pressure. However, key airflow characteristics did not differ among subjects with CLP, were they affected or not by OSA.

Addressing the Gender Gap in Academic Success: A History of the University of North Carolina Association of Professional Women in the Medical Sciences

Despite efforts at many institutions, nationally, women still lag behind their male counterparts in leadership, promotion, and seniority. In this paper, we describe the efforts to improve the environment for women faculty at one large academic medical center through the creation of an Association of Professional Women in Medical Sciences. Over the years, the group has helped influence policies that directly affect women faculty, provided high-yield programming on topics related to women's success, and created interprofessional networking opportunities for women faculty. We describe the challenges and successes of this group to serve as a model and inspiration for other institutions.

Multi-institutional Evaluation of Radiologic Findings Associated With Pediatric Congenital Idiopathic Bilateral Vocal Fold Dysfunction

OBJECTIVE

To report brain magnetic resonance imaging (MRI) and ultrasonography findings in pediatric patients with congenital idiopathic bilateral vocal fold dysfunction and analyze factors associated with its etiology and resolution.

STUDY DESIGN

Case series with retrospective review.

SETTING

Tertiary care multi-institutional setting: Nationwide Children's Hospital, Indiana University, University of North Carolina, and Cleveland Clinic.

METHODS

Pediatric patients with congenital idiopathic bilateral vocal fold dysfunction were included in this review.

RESULTS

Congenital idiopathic bilateral vocal fold dysfunction was identified in 74 patients from 2000 to 2018. Brain MRI scans were performed in all patients and ultrasonography in 30 (40.5%). Normal imaging results were most commonly found in patients born full-term (P < .0001) or via vaginal delivery (P < .01). Abnormal brain MRI and ultrasound results were found in 38 of 74 (51.3%) and 16 of 30 (53.3%), respectively. Type I Chiari malformation was not identified in any patient. No specific brain MRI or ultrasound abnormality was associated with patients' bilateral vocal fold dysfunction. Complete/incomplete bilateral vocal fold resolution occurred in 45 of 74 (60.8%) patients over the study interval and was not associated with brain MRI or ultrasound findings or birth complications but was associated with vaginal delivery (P = .02). Resolution rates were highest for patients with bilateral vocal fold paramedian paralysis (P = .05).

CONCLUSIONS

In this multi-institutional study, no specific brain MRI or ultrasound abnormality was associated with patients' bilateral vocal fold dysfunction or subsequent resolution rates. While imaging is often performed to detect and treat any reversible causes of bilateral vocal fold dysfunction, in this series, imaging findings were heterogeneous and did not identify any treatable causes, such as type I Chiari malformation.

Provision and Utilization of Team- and Community-Based Operative Care for Patients With Cleft Lip/Palate in North Carolina

OBJECTIVE

To characterize operative care for cleft lip and/or palate (CL/P) based on location (ie, from American Cleft Palate Craniofacial Association [ACPA]-approved multidisciplinary teams or from community providers).

DESIGN

Cross-sectional analysis of Healthcare Cost and Utilization Project State Inpatient Database and State Ambulatory Surgery & Services Database databases for North Carolina from 2012 to 2015.

SETTING/PATIENTS AND MAIN OUTCOME MEASURES

Clinical encounters for children with CL/P undergoing operative procedures were identified, classified by location as "Team" versus "Community," and characterized by demographic, geographic, clinical, and procedural factors. A secondary evaluation reviewed concordance of team and community practices with an ACPA guideline related to coordination of care.

RESULTS

Three teams and 39 community providers performed a total of 3010 cleft-related procedures across 2070 encounters. Teams performed 69.7% of total volume and performed the majority of cleft procedures, including cleft lip repair, palate repair, alveolar bone grafting, and correction of velopharyngeal insufficiency. Community locations principally offered myringotomy and rhinoplasty. Team care was associated with higher guideline concordance.

CONCLUSIONS

American Cleft Palate Craniofacial Association -approved team-based care accounts for the majority of cleft-related care in North Carolina; however, a substantial volume of cleft-related procedures was provided by community providers, with 3 providers accounting for the vast majority of community cases.

Is there an advantage to using computer aided detection for the early detection of pulmonary nodules within chest X-Ray imaging?

OBJECTIVE

Using published literature, this research examines whether Computer-aided Detection (CAD) identifies more Pulmonary Nodules (PN) within Chest X-ray (CXR) systems, compared to radiologist diagnosis without CAD.

KEY FINDINGS

Although the primary papers were pointing to CAD being a beneficial system in the diagnosis of PN detection, a regression analysis of the data available within these papers showed no correlation between the higher sensitivity of CAD against the detrimental high False Positives (FP) of CAD. Findings of the studies were deemed inconclusive.

CONCLUSION

Further research is recommended to review the potential of CAD on CXR PN detection.

IMPLICATIONS FOR PRACTICE

CAD acting as a second reader could potentially reduce interpreter error rate.

Proceedings of resources for optimal care of acute care and emergency surgery consensus summit Donegal Ireland

BACKGROUND

Opportunities to improve emergency surgery outcomes exist through guided better practice and reduced variability. Few attempts have been made to define optimal care in emergency surgery, and few clinically derived key performance indicators (KPIs) have been published. A summit was therefore convened to look at resources for optimal care of emergency surgery. The aim of the Donegal Summit was to set a platform in place to develop guidelines and KPIs in emergency surgery.

METHODS

The project had multidisciplinary global involvement in producing consensus statements regarding emergency surgery care in key areas, and to assess feasibility of producing KPIs that could be used to monitor process and outcome of care in the future.

RESULTS

Forty-four key opinion leaders in emergency surgery, across 7 disciplines from 17 countries, composed evidence-based position papers on 14 key areas of emergency surgery and 112 KPIs in 20 acute conditions or emergency systems.

CONCLUSIONS

The summit was successful in achieving position papers and KPIs in emergency surgery. While position papers were limited by non-graded evidence and non-validated KPIs, the process set a foundation for the future advancement of emergency surgery.

Technical characteristics of elite junior men and women race walkers

AIM

Successful coaching in race walking requires a thorough understanding of the biomechanical principles underlying this unique form of gait. The purpose of this study was to analyze elite male and female junior race walkers and identify key kinematic variables.

METHODS

Twenty junior men and 20 junior women were videoed as they competed over 10 km in the 8th European Cup Race Walking. Three-dimensional kinematic data were obtained using motion analysis software (SIMI, Munich).

RESULTS

Step length and cadence were correlated with speed in both sexes, and greater step lengths were the kinematic reason for junior men's faster walking speeds. While cadence did not differ between junior men and junior women, there was a difference in proportion of step time spent in contact. There were some differences between genders for upper body joint angles (e.g., elbow) but there were few differences within lower limb joint angles.

CONCLUSION

Although some technical aspects (e.g., pelvic and shoulder girdle rotation) appeared undeveloped, it was noteworthy that most athletes achieved full knee extension at initial contact in accordance with the rules. However, in many athletes flight times were evident that might present problems during the transition to the higher standards of senior competition. There was a large range of ability among both sexes and coaches are advised to ensure that technical development continues during the transition to senior competition.

Parental perceptions and morbidity: tracheostomy and Pierre Robin sequence

OBJECTIVE

Evaluate parental perceptions associated with tracheostomy morbidity and quality of life in the management of Pierre Robin Sequence (PRS).

STUDY DESIGN

Retrospective review/survey.

METHODS

42 Pierre Robin patients were identified, records were reviewed and airway assessments evaluated relative to airway compromise. Twenty patients had undergone tracheostomy. Perceptions of quality of life/morbidity related to tracheostomy were assessed using parental surveys.

RESULTS

31/41 (76%) patients participated in the survey. 15/31 (48%) of survey participants required tracheostomy and were decannulated after a mean of 28 months. Of the patients who had undergone tracheostomy, 10/15 (67%) had isolated Pierre Robin (iPRS) and the remaining 5/15 (33%) had syndromes associated with Pierre-Robin (sPRS). 9/10 (90%) iPRS and 4/5 (80%) sPRS families' expectations were met regarding expected duration of tracheostomy although 3/5 (60%) sPRS, and 8/10 (80%) iPRS described the overall experience as difficult. Of the 2/15 patient's families who were dissatisfied 1 patient had iPRS and the other sPRS. 9/15 (60%) required multiple > or = 3) hospitalizations. 3/13 (23%) reported airway problems after decannulation and 2/15 (13%) remained tracheostomy dependent at the time of survey. Prolonged tracheostomy duration represented a significant parental concern.

CONCLUSIONS

A subset of patients required extended duration of tracheostomy; some continued to have airway problems after decannulation and/or distraction. Although some patients benefit from early mandibular distraction other Pierre Robin patients have multi-level obstruction requiring additional therapies and often tracheostomy. Parental concerns and perceptions relative to tracheostomy have not been adequately studied for Pierre Robin airway obstruction. Of those responding to this survey, the majority of parents' expectations were met regarding tracheostomy. Of those whose expectations were not met, it seems that better pre-intervention counseling regarding length of tracheostomy tube dependence, as well as a discussion about potential complications and hospitalizations frequently associated with prolonged tracheostomy, may lead to improved parental expectations.

Soluble receptor for advanced glycation end products in multiple sclerosis: a potential marker of disease severity

OBJECTIVES

To compare serum levels of the receptor for advanced glycation end products (sRAGE) between multiple sclerosis (MS) patients and healthy control subjects, and to investigate whether serum sRAGE levels correlate with MS disease severity as indicated by the Kurtzke Expanded Disability Status Scale (EDSS).

METHOD

37 patients with clinical diagnosis of MS and 22 healthy control subjects were investigated in a cross-sectional study using enzyme-linked immunosorbent assays (ELISA).

RESULTS

Serum levels of sRAGE were found to be significantly lower in MS patients compared to levels in healthy controls (p = 0.005). A trend toward lower levels of serum sRAGE was observed in female MS patients compared to their male counterparts (p = 0.05). A relationship between sRAGE and EDSS, and sRAGE and rate of clinical relapse was observed (p = 0.012).

CONCLUSION

The significant reduction of sRAGE in MS patients relative to healthy controls supports the potential role for RAGE axis in MS clinical pathology. Lower levels of sRAGE may be associated with enhanced inflammatory responses. Based on these observations, further investigations into the role of sRAGE in MS clinical pathology is warranted.

Statins and fibrates for preventing melanoma

BACKGROUND

Effective treatment for advanced melanoma is lacking. While no drug therapy currently exists for prevention of melanoma, in vitro, case-control, and animal model evidence suggest that lipid-lowering medications, commonly taken for high cholesterol, might prevent melanoma.

OBJECTIVES

To assess the effects of statin or fibrate lipid-lowering medications on melanoma outcomes.

SEARCH STRATEGY

We searched the Cochrane Skin Group Specialised Register (February 2003), CENTRAL (The Cochrane Library Issue 1, 2005), MEDLINE (to March 2003), EMBASE (to September 2003), CANCERLIT (to October 2002), Web of Science (to May 2003), and reference lists of articles. We approached study investigators and pharmaceutical companies for additional information (published or unpublished studies).

SELECTION CRITERIA

Trials involving random allocation of study participants, where experimental groups used statins or fibrates and participants were enrolled for at least four years of therapy.

DATA COLLECTION AND ANALYSIS

Three authors screened 109 abstracts of articles with titles of possible relevance. We then thoroughly examined the full text of 72 potentially relevant articles. We requested unpublished melanoma outcomes data from the corresponding author of each qualifying trial.

MAIN RESULTS

We identified 16 qualifying randomised controlled trials (RCTs) (seven statin, nine fibrate). Thirteen of these trials (involving 62,197 participants) provided data on incident melanomas (six statin, seven fibrate). A total of 66 melanomas were reported in groups receiving the experimental drug and 86 in groups receiving placebo or other control therapies. For statin trials this translated to an odds ratio of 0.90 (95% confidence interval 0.56 to 1.44) and for fibrate trials an odds ratio of 0.58 (95% confidence interval 0.19 to 1.82). Subgroup analyses failed to show statistically significant differences in melanoma outcomes by gender, melanoma occurrence after two years of participation in trial, stage or histology, or trial funding. Subgroup analysis by type of fibrate or statin also failed to show statistically significant differences, except for the statin subgroup analysis which showed reduced melanoma incidence for lovastatin, based on one trial only (odds ratio 0.52, 95% confidence interval 0.27 to 0.99).

AUTHORS' CONCLUSIONS

The melanoma outcomes data collected in this review of RCTs of statins and fibrates does not exclude the possibility that these drugs prevent melanoma. There was a 10% and 42% reduction for participants on statins and fibrates, respectively, however these results were not statistically significant. Until further evidence is established, limiting exposure to ultraviolet radiation remains the most effective way to reduce the risk of melanoma.

Variable assortative mating in replicate mating trials using Drosophila melanogaster populations derived from contrasting opposing slopes of 'Evolution Canyon', Israel

Significant assortative mating in laboratory studies has been previously shown between two populations of Drosophila melanogaster collected from micro-climactically contrasting and opposing slopes of 'Evolution Canyon' (Lower Nahal Oren, Israel; Korol et al., 2000). Coupled with evidence that the two populations are adapted to their respective environments, this has been suggested as a rare example of ongoing behaviourally mediated speciation occurring in the face of gene flow. Reproductive isolation between these populations, however, has never been confirmed by replicate experiments in an independent laboratory. For this reason, we tested recent collections of these populations for premating isolation in both the original (Haifa) and a new (Burnaby) laboratory under a variety of experimental protocols. Although non-random mating was found in the majority of trials conducted in Haifa, we were unable to replicate these strong results in Burnaby. Most notably, we failed to detect assortative mating in four separate double choice experiments. Significant non-random mating was detected, however, in three of six single choice experiments in Burnaby, suggesting that the populations are behaviourally differentiated in some manner. Why nonrandom mating was weaker in Burnaby than Haifa is not understood, but suggests that assortative mating may be sensitive to unknown environmental factors.

Use of rigid and flexible bronchoscopy among pediatric otolaryngologists

OBJECTIVE

To explore how rigid and flexible bronchoscopy are used in pediatric otolaryngologic practice.

DESIGN

Survey.

PARTICIPANTS

Members of the American Society of Pediatric Otolaryngology who practice in the United States and Canada and were listed in the membership directory were eligible. Of the 206 members, 24 practicing outside the United States or Canada and 11 without an e-mail address or a fax machine were excluded. Hence, a questionnaire was e-mailed or faxed to 171 pediatric otolaryngologists.

MAIN OUTCOME MEASURES

Questions concerned the practice setting, type and number of bronchoscopies, indications, complications, and medicolegal cases.

RESULTS

Responses were received from 120 subjects (70.2%), with 3 retired and 2 practicing only otology, leaving 115 respondents who completed at least some of the questionnaire. Rigid and flexible bronchoscopy were performed by 72.7% (56/77) of those in academic settings and by 71.1% (27/38) of those in group or solo practices. In the last 12 months, approximately 10 454 total bronchoscopies were performed, with 2052 flexible and 9117 rigid bronchoscopies. Stridor, suspected foreign body inhalation, and laryngomalacia were the most common indications for bronchoscopy. Of the 83 respondents practicing rigid and flexible bronchoscopy, 25 (30.1%) used both instruments to manage complex or repeated foreign bodies, 25 (30.1%) used both to manage patients with cystic fibrosis, and 15 (18.1%) used both to manage simple foreign bodies. Complications were reported by 15.7% of the respondents, the most common being arrhythmia. Familiarity with a case resulting in medicolegal action was reported by 32.2% of the respondents.

CONCLUSIONS

Rigid and flexible bronchoscopy have multiple uses in pediatric otolaryngologic practice. Also, flexible bronchoscopy appears to be emerging as a more frequently used diagnostic and therapeutic tool.

Enantioselective biotransformation of aryl-isopropyl, -isopropenyl, and -propenyl groups by the rabbit or by the rat

Thirteen kinds of aromatic compounds (Alkyl- and alkenyl-) were administered to rabbits and the chiralities of their optical active metabolite were determined by the synthesis of the enantiomers or their derivatives. This work has revealed many examples of enantioselective biotransformations and chiral inversion in the rabbits and mechanisms for this inversion have been proposed. The enantioselective hydration of transanethole epoxide was also examined in vitro in rat liver microsomes and possible mechanisms of this process are also discussed.

Effectiveness of patient delivered partner medication for preventing recurrent Chlamydia trachomatis

OBJECTIVE

To determine if providing Chlamydia trachomatis infected women with medication to deliver to their sex partner(s) could reduce recurrent chlamydia infections compared with the standard partner referral method.

STUDY DESIGN

A observational cohort study of 178 women, 14-39 years old attending a family planning clinic, diagnosed and treated for C trachomatis between October 1993 and December 1994 was conducted (43 received patient delivered partner medication (PDPM) and 135 received partner referral cards). Women were retested before or at their annual visit.

RESULTS

The mean time of follow up was 17.7 months (SD 7.7). The PDPM group (n = 43) was similar to partner referral group (n = 135) for age, race, contraceptive method, history of an STD, and follow up time. The annual recurrent infection rate was lower among the PDPM group compared with the partner referral group (11.5% v 25.5%, p < 0.05). After adjusting for age in logistic regression, women in the PDPM group were less likely than women in the partner referral group to have an incident C trachomatis infection (OR 0.37, 95% CI 0.15-0.97, p < 0.05).

CONCLUSION

These findings suggest that patient delivered partner medication can protect women from recurrent C trachomatis infection compared with the standard partner referral approach. Prospective studies with larger sample sizes are under way.

Analysis of the architecture of the transcription factor sigma N (sigma 54) and its domains by circular dichroism

Enhancer-dependent transcription in bacteria requires the alternative transcription factor sigma N (sigma 54), which forms an RNA polymerase holoenzyme that binds promoters as a transcriptionally inactive complex. We have examined the structure of sigma N by circular dichroism (CD) analysis. The sigma N protein and its domains are well structured in the absence of the core RNA polymerase subunits or promoter DNA. Denaturation of sigma N by temperature as followed by changes in CD shows a concomitant loss of secondary and tertiary structures with a melting temperature of 36 degrees C. The secondary structure displays a two-state melting curve with a second Tm of 85 degrees C. The amino-terminal Region I activation domain together with the acidic Region II does not contribute to the two-state melting. In marked contrast, the integrity of the C-terminal DNA-binding domain is required for the two-state melting. Measurements of pKb also demonstrated that a C-terminal part of sigma N, but not regions I or I + II, is required for the structural integrity of sigma N at high pH. Measurements of pKa suggested that alpha-helical structures are important in sigma N for the establishment of tertiary structural elements. The tertiary structure near ultraviolet CD signals of sigma N do not require regions I or I + II but were strongly diminished by C-terminal truncation of sigma N. Promoter DNA binding resulted in a conformational change in sigma N, permitting the determination of a binding constant. A typical B-DNA conformation was adopted by the promoter DNA. Implications for the modular domain organization of sigma N, the function of C-terminal sequences, and domain communication and its role in activation of transcription are discussed.

Purification and activities of the Rhodobacter capsulatus RpoN (sigma N) protein

The rpoN-encoded sigma factors (sigma N) are a distinct class of bacterial sigma factors, with no obvious homology to the major sigma 70 class. The sigma N-containing RNA polymerase holoenzyme functions in enhancer-dependent transcription to allow expression of positively controlled genes. We have purified the Rhodobacter capsulatus sigma N protein, which is distinctive in lacking an acidic region implicated in the melting of promoter DNA by the Escherichia coll sigma N holoenzyme, and may represent a minor subclass of sigma N proteins. Assays of promoter recognition and holoenzyme formation and function showed that the purified R. capsulatus sigma N protein is distinct in activity compared to the enteric proteins, but retains the broad functions described for these proteins. As first described for the Klebsiella pneumoniae protein, promoter recognition in the absence of core RNA polymerase was detected, but contact of certain promoter bases by the R. capsulatus sigma N protein and its response to core RNA polymerase was clearly different from that determined for the K. pneumoniae and E. coli proteins. Results are discussed in the context of a requirement to modulate the activity of the DNA-binding surfaces of sigma N to regulate sigma N function. Circular dichroism was used to evaluate the structure of the R. capsulatus protein and revealed differences in the tertiary signals as compared to the K. pneumoniae protein, some of which are attributable to the DNA-binding domain of sigma N.

Imaging of nasopharyngeal atresia

CT and MR revealed a case of nasopharyngeal atresia, a malformation in which the soft palate is not formed, and the hard palate extends posteriorly to fuse with the anterior surface of the clivus, resulting in complete isolation of the nasal and oral cavities and the absence of a nasopharynx. We believe this rare anomaly results from abnormal persistence of the embryologic bucconasal plate and/or anomalous migration of the nasoseptal elements.

Identification of middle ear dysfunction in young children: a comparison of tympanometric screening procedures

Two acoustic immittance screening procedures were evaluated in conjunction with pneumatic otoscopy, performed by a pediatric otolaryngologist. The subjects were 204 3- and 4-yr-old children from a rural area in eastern North Carolina. Pass-fail criteria were examined using two middle ear screening procedures: (1) a "traditional" procedure based on measures of tympanometric peak pressure and acoustic reflexes, and (2) the tympanometric measures contained within the American Speech-Language-Hearing Association's (ASHA) revised Guidelines for Screening for Hearing Impairment and Middle Ear Disorders. The traditional procedure resulted in low specificity but high sensitivity, whereas ASHA's immittance procedure resulted in high specificity but only moderate sensitivity. The negative predictive value was very high for both procedures; however, positive predictive value was low, especially for the traditional procedure. Advantages and disadvantages of the two procedures and future research needs are discussed.

Pyrimidine nucleotide synthesis in the rat kidney in early diabetes

Early renal hypertrophy of diabetes is associated with increases in the tissue content of RNA, DNA, and sugar nucleotides involved in the formation of carbohydrate-containing macromolecules. We have previously reported an increase in the activity of enzymes of the de novo and salvage pathways of purine synthesis in early diabetes; the present communication explores the changes in the pathways of pyrimidine synthesis. Measurements have been made of key enzymes of the de novo and salvage pathways at 3, 5, and 14 days after induction of diabetes with streptozotocin (STZ), phosphoribosyl pyrophosphate (PPRibP), and some purine and pyrimidine bases. Carbamoyl-phosphate synthetase II, the rate-limiting enzyme of the de novo route, did not increase in the first 5 days after STZ treatment, the period of most rapid renal growth; a significant rise was seen at 14 days (+38%). Dihydroorotate dehydrogenase, a mitochondrial enzyme, showed the most marked rise (+147%) at 14 days. The conversion of orotate to UMP, catalyzed by the enzymes of complex II, was increased at 3 days (+42%), a rise sustained to 14 days. The salvage route enzyme, uracil phosphoribosyltransferase (UPRTase), showed a pattern of change similar to complex II. The effect of the decreased concentration of PPRibP on the activities of CPSII, for which it is an allosteric activator, and on activities of OPRTase and UPRTase, for which it is an essential substrate, is discussed with respect to the relative Ka and Km values for PPRibP and the possibility of metabolite channeling.

Surgical applications of ultrathin flexible bronchoscopes in infants

Ultrathin flexible bronchoscopes with controlled distal angulation allow the conventional diagnostic examination of the lower airways of even the smallest infants. These instruments may be passed through small endotracheal or tracheostomy tubes while ventilation is maintained. It is thus possible, under direct visualization, to control the manipulation of surgical instruments where they could not otherwise be seen, or to study airway dynamics and anatomy intraoperatively without extubating the patient.

Asymmetric synthesis of a precursor for the automated radiosynthesis of S-(3'-t-butylamino-2'-hydroxypropoxy)-benzimidazol-2-[11C]one (S-[11C]CGP 12177) as a preferred radioligand for beta-adrenergic receptors

S-[1-(2,3-Diaminophenoxy)]-3'-(N-t-butylamino)propan-2'-ol has been synthesized in three steps from 2,3-dinitro-phenol and the chiral auxiliary, S-glycidyl-3-nitrobenzenesulphonate, to provide a precursor for labelling S-(3'-t-butylamino-2'-hydroxypropoxy)-benzimidazol-2-one (S-CGP 12177) with the short-lived positron-emitting radionuclide, carbon-11 (t 1/2 = 20.4 min; beta+ = 99.8%). Reaction of the diamine with [11C]phosgene, itself derived from no-carrier-added cyclotron-produced [11C]methane, provides radiochemically and chemically pure S-[carbonyl-11C]CGP 12177 in greater than 95% enantiomeric excess after HPLC. Automated apparatus is described for safely producing up to 5.9 GBq (160 mCi) of S-[11C]CGP 12177 with high sp. act. (20-40 GBq/mu mol or 0.54-1.08 Ci/mu mol) in a form suitable for human intravenous injection at only 30 min from the end of radionuclide production. S-[11C]CGP 12177 is preferred to the formerly described racemate as a radioligand for the study of beta-adrenergic receptors in vivo by positron emission tomography.

Conformational effects of nucleotide exchange in ras p21 proteins as studied by fluorescence spectroscopy

The intrinsic fluorescence properties of the oncogene protein p21N-ras,p21H-ras and one of its transforming mutants, p21N-ras (Val12), have been investigated. A mutant containing a single tryptophan at position 28 in p21H-ras (Trp28) has been specifically engineered to provide a probe of protein conformation on nucleotide binding. The proteins produced essentially similar circular dichroism spectra typical of alpha/beta proteins. A decrease in the intensity of the fluorescence emission spectrum due to tyrosine occurred on GDP/GTP nucleotide exchange in the native and mutant proteins. Selective excitation of the single tryptophan in p21 produced a decrease in fluorescence intensity which was accompanied by a blue shift in the wavelength of maximum emission on nucleotide exchange. A reduction in the residual Mg2+ ion concentration enhanced this effect.

Circular dichroic spectra of elapid cardiotoxins

Cardiotoxins isolated from elapid snake venoms constitute a chemically homogeneous family of molecules. Within this group several biologically different subclasses exist. We report a comparative analysis of the structure of 20 cardiotoxins using circular dichroism, immunological methods and secondary-structure prediction. It is shown that cardiotoxins fall within two structural subclasses. Toxins of group I are characterized by (a) CD spectra having an intense positive band close to 192.5 nm and a negative trough at 225 nm with no positive band around 230 nm, (b) strong cross-reactivity with a polyclonal antiserum specific for Naja nigricollis toxin gamma and (c) a high tendency to form a reverse turn in the region of position 11. Toxins of group II are characterized by (a) CD spectra displaying a much weaker positive band at 192.5 nm, a negative band around 210 nm and a positive band at 230 nm, (b) little cross-reactivity with the aforementioned antiserum and (c) a high reverse-turn potential at position 31. It is suggested that the observed differences result from differing curvatures in the antiparallel beta sheet which constitutes the main secondary structure of cardiotoxins.

The cordycepin analogue of 2,5A and its threo isomer. Chemical synthesis, conformation and biological activity

A new synthesis of the cordycepin analogue of 2,5A and its threo isomer is reported along with an assessment of their conformations by circular dichroism spectroscopy. Evidence is also presented showing that these compounds are stable against 2,5A-specific phosphodiesterase and are not able to activate the 2,5A-dependent endoribonuclease, possibly due to a reduced binding to the latter enzyme as compared to that of 2,5A.

Characterization of haem disorder by circular dichroism

Native and reconstituted myoglobin were prepared and their c.d. spectra recorded in the Soret region. Time-dependent changes in dichroism following reconstitution were observed and related to haem orientational disorder. Comparative c.d. studies, in agreement with n.m.r. studies, reveal that the degree and nature of this disorder are species-dependent.

Alteration of aminoglycoside antibiotic ototoxicity: effect of semistarvation

The effect of semistarvation on the toxicity and ototoxicity of tobramycin sulfate (TO) and gentamicin sulfate (GE) was investigated in guinea pigs by electrophysiological and histopathological methods. The presented data has shown that the toxicity and ototoxicity of aminoglycoside antibiotics is substantially increased when guinea pigs were semistarved. Our results should also warn researchers using semistarvation in their conditioning experiments which investigate the toxicity of different chemicals. Toxicity was greater in GE- than TO-treated animals, which caused the GE-treated animals to die during treatment or shortly after treatment. Thus, TO should be preferentially used because it has been shown to be less toxic and ototoxic in normal and altered nutritional conditions.

Alteration of aminoglycoside antibiotic ototoxicity by hyper- and hypohydration

The ototoxicities of tobramycin sulfate and gentamicin sulfate were investigated in guinea pigs under conditions of normal, increased, and decreased hydration. Increased hydration was associated with no decline in the amplitude of the cochlear microphonics, a lesser decline in the eighth nerve action potentials and lesser damage to the organ of Corti. Decreased hydration was associated with an increase in the threshold of the cochlear microphonics and the eighth nerve action potentials, a decline in the amplitude of the cochlear microphonics, a greater decline in the eighth nerve action potentials, and greater damage to the organ of Corti. Tobramycin sulfate was substantially less toxic than gentamicin sulfate with normal, increased and decreased hydration. These findings suggest the preferential use of tobramycin sulfate for patients with normal renal function, and especially patients with renal impairment.

The role of the cardiac nerves in regulation of sodium excretion in conscious dogs

Conscious, chronically instrumented dogs, maintained on a high sodium intake, were used to investigate whether surgical cardiac denervation impairs the natriuresis associated with left atrial pressure increase produced in three ways: during an increase in left atrial pressure by means of a reversible mitral stenosis (protocol 1); after an i.v. saline load (1.0 ml 0.9% saline min-1 . kg-1 over 60 min) (protocol 2); after an oral saline load (14.5 mmol Na . kg-1 given with the food as isotonic solution) (protocol 3). During a reversible mitral stenosis, in intact dogs, urine volume and sodium excretion increased markedly (from 34--145 microliters . min-1 . kg-1 and from 3--12 mumol . min-1 . kg-1); mean arterial pressure increased by an average of 2 kPa (15 mm Hg) and heart rate by 53 b/min; plasma renin activity fell from 0.37--0.21 ng AI . ml-1 . h-1 . Cardiac denervation eliminated these effects of left atrial distension except for a small increase in heart rate (12 b/min). This indicates that the natriuresis and diuresis during left atrial distension resulted from stimulation of receptors located in the left atrium. In contrast, during protocol 2 and 3, the same amounts of sodium and water were excreted in the cardiac denervated dogs as compared to the intact dogs. A comparable decrease in plasma renin activity also was observed. -- Apparently the presence of the cardiac nerves is not a prerequisite for maintenance of sodium and water homeostasis.