An Unusual Case of a Primary Hyperparathyroidism Mimic

A 32-year-old lady with a history of bulimia nervosa was noted to have a raised adjusted calcium of 2.94mmol/L associated with high parathyroid hormone (PTH) 17.2pmol/L. On review, she had an apparent hypercalcaemia for at least three years, and also had a chronic, severe alkalosis with a bicarbonate up to 81.9mEQ/L. Ionised calcium during that time had actually been low, down to 1.03mmol/L. This case highlights the effects of alkalosis on calcium, as more albumin is available for binding to ionised calcium. This results in a low ionised calcium, which triggers PTH release and overall leads to raised adjusted calcium levels. Clinicians may misdiagnose a similar patient with primary hyperparathyroidism and treatment would cause worsening of true hypocalcaemia.

P1854Clinical implications of physical function and resilience in patients undergoing transcatheter aortic valve implantation

Background

Gait speed, as a measure of physical function and marker of frailty, is now routinely screened when evaluating patients with aortic stenosis (AS) for transcatheter aortic valve implantation (TAVI). Assessment of physical function is important to identify patients for whom TAVI may be futile and to assign patients to a procedural risk category. After TAVI, patients may exhibit physical resilience (improvement in physical function) or vulnerability (worsening). Characterizing the trajectory and clinical consequences of physical function after TAVI represent knowledge gaps in the field.

Purpose

Evaluate associations between physical resilience (improved gait speed) vs vulnerability (decline) after TAVI and subsequent death/hospitalization.

Methods

The REPRISE III trial compared a mechanically-expanded vs a self-expanding valve in 912 high/extreme risk patients with symptomatic AS. Patients (n=587) who underwent valve implantation and who had a gait speed recorded both pre- and 1-year post-TAVI were analyzed. Gait speed is based on the 5m walk test (slow: 5m in >6s, <0.83m/s; normal: ≥0.83m/s). Trajectory of physical function after TAVI was characterized in 2 ways. Model 1 examined 4 groups based on slow or normal gait speeds at baseline and 1-year post-TAVI. Model 2 examined gait speed change pre-TAVI to 1 year (adjusted for baseline gait speed). Using a landmark approach, the relationships between baseline and 1-year gait speed were evaluated in multivariable Cox PH models of outcomes between 1 and 2 years post-TAVI.

Results

A clinically-meaningful improvement (≥0.1m/s), no change (±0.1m/s), or decline (≥0.1/ms) in gait speed 1 year after TAVI was observed in 39%, 36%, and 26% of patients, respectively. Among the 4 groups defined by pre- and 1-year post-TAVI gait speeds, 1 to 2 year mortality or hospitalization rates were: 6.6% (normal/normal), 20.9% (normal/slow), 8.0% (slow/normal), and 21.5% (slow/slow). Adjusted hazard ratios of the 2 models are shown (Table).

Table. Outcome by Change in Gait Speed Death/Hospitalization P-value Death P-value Hospitalization P-value Adjusted HR [95% CI] Adjusted HR [95% CI] Adjusted HR [95% CI] Model 1: Baseline/1 year Gait Speed   (Normal/Normal (n=150) [referent])   Normal/Slow (n=59) 3.82 [1.61, 9.08] <0.01 2.75 [0.96, 7.86] 0.06 7.31 [1.94, 27.58] <0.01   Slow/Normal (n=114) 1.39 [0.53, 3.59] 0.50 1.44 [0.50, 4.12] 0.50 1.69 [0.38, 7.60] 0.49   Slow/Slow (n=253) 3.88 [1.91, 7.91] <0.01 2.36 [1.02, 5.46] 0.045 3.89 [1.14, 13.27] 0.03 Model 2: Gait speed change   Baseline to 1 year per 0.1m/s increase 0.83 [0.74, 0.92] <0.01 0.92 [0.80, 1.04] 0.19 0.75 [0.64, 0.88] <0.01

Conclusion

These data reveal there is marked heterogeneity in the trajectory of physical function after TAVI and that this trajectory–more so than baseline physical function–is clinically consequential. Identifying and optimizing factors associated with physical resilience after TAVI may improve outcomes.

Acknowledgement/Funding

Boston Scientific

Comparison of two anthropomorphic phantoms as a calibration tool for whole-body counter using Monte Carlo simulations

The whole-body counting facility at the Indira Gandhi Centre for Atomic Research uses an in-house built Masonite cut-sheet phantom for the calibration of whole-body monitors. Recently, an Indian Adult BOMAB phantom was procured as an additional utility to augment the facility. The present study is to generate full-energy peak efficiencies (FEPE) of the shielded chair (SC) whole-body counting system using the new BOMAB phantom through Monte Carlo (MC) simulations. The values are compared with that of the Masonite phantom. First, the SC was modelled along with the Masonite phantom to estimate the FEPE values and Compton scattering factors (CSFs) for different energies. The simulated values were validated against the measurements using the Masonite cut-sheet phantom (Masonite phantom). The validated SC model was used along with the Indian adult BOMAB phantom to estimate the FEPEs and the CSFs. The simulated BOMAB phantom values were compared with the simulated Masonite phantom values. The maximum deviation for both the FEPEs and CSFs was ±10% validating the use of the Masonite phantom as a calibration tool representing an Indian adult.

Prediction of background in low-energy spectrum of Phoswich detector

In vivo monitoring of actinides in occupational workers is done using Phoswich detector by measuring the low-energy X ray and gamma rays. Quantification of actinides like plutonium and americium in the lungs is extremely difficult due to higher background in the low-energy regions, which is from ambient background as well as from the subject. In the latter case, it is mainly due to the Compton scattering of body potassium, which varies person-to-person. Hence, an accurate prediction of subject-specific background counts in the lower-energy regions is an essential element in the in vivo measurement of plutonium and americium. Empirical equations are established for the prediction of background count rate in (239)Pu and (241)Am lower-energy regions, called 'target regions', as a function of count rate in the monitoring region (97-130 keV)/(40)K region in the high-energy spectrum, weight-to-height ratio of the subject (scattering parameter) and the gender.

Note: High density pulsed molecular beam for cold ion chemistry

A recent expansion of cold and ultracold molecule applications has led to renewed focus on molecular species preparation under ultrahigh vacuum conditions. Meanwhile, molecular beams have been used to study gas phase chemical reactions for decades. In this paper, we describe an apparatus that uses pulsed molecular beam technology to achieve high local gas densities, leading to faster reaction rates with cold trapped ions. We characterize the beam's spatial profile using the trapped ions themselves. This apparatus could be used for preparation of molecular species by reactions requiring excitation of trapped ion precursors to states with short lifetimes or for obtaining a high reaction rate with minimal increase of background chamber pressure.

KAP study conducted to assess the impact of special health education campaign for control of dengue at Vellore in Tamil Nadu

An abnormal increase in the incidence of dengue was reported at Vellore Corporation since September 2012. Intensive control operations supported with health education campaigns were carried out from September to November 2012 till the outbreak situation subsided. During December 2012, a cross sectional survey was conducted at Vellore Corporation to assess the impact of the health education campaigns on the knowledge, attitude and practice in the community and also to assess future needs. A total of 101 families from four different locations at Vellore corporation were interviewed on pre-structured formats. Though 80% of the respondents felt that dengue could be effectively prevented and controlled only with community participation, majority of them lacked awareness on the day time biting behaviour of Aedes mosquitos, their indoor resting and breeding habits and relevance of specific control measures focused on the bionomics of dengue vectors.

Calibration of phoswich-based lung counting system using realistic chest phantom

A phoswich detector, housed inside a low background steel room, coupled with a state-of-art pulse shape discrimination (PSD) electronics is recently established at Radiological Safety Division of IGCAR for in vivo monitoring of actinides. The various parameters of PSD electronics were optimised to achieve efficient background reduction in low-energy regions. The PSD with optimised parameters has reduced steel room background from 9.5 to 0.28 cps in the 17 keV region and 5.8 to 0.3 cps in the 60 keV region. The Figure of Merit for the timing spectrum of the system is 3.0. The true signal loss due to PSD was found to be less than 2 %. The phoswich system was calibrated with Lawrence Livermore National Laboratory realistic chest phantom loaded with (241)Am activity tagged lung set. Calibration factors for varying chest wall composition and chest wall thickness in terms of muscle equivalent chest wall thickness were established. (241)Am activity in the JAERI phantom which was received as a part of IAEA inter-comparison exercise was estimated. This paper presents the optimisation of PSD electronics and the salient results of the calibration.

A study on the resting preference of mosquito species in wells in Vellore in Tamilnadu, South India

The resting preferences of mosquito species was investigated in domestic wells. In addition to the routine adult surveys in human dwellings, adult collections were also made in domestic wells using an innovated equipment operating on the principles of spray sheet collections. Above the water surface, wells provide humid and dark microclimate along the inner walls. It has been observed that this microclimate provides very congenial resting place for few mosquito species; specially for the males and for the females between their gonotropic cycles. Larval collections in the wells did not reveal breeding of majority of the mosquito species collected by this technique. Investigations were conducted in 87 wells in 11 localities during 2005. A total of 4969 mosquitos were collected of which 69.1% (3441) were males and 30.9% (1528) were females. From among the mosquitos collected 96.5% were Cu. quinquifasciatus, 0.26% All stephensi, 3.0% Aedes agypti and 0.24% Armegeres sp. The results of the analysis of the physical and chemical parameter of water samples of the study wells before and after the surveys endorsed the utility of this technique for entomological investigations in outbreak situations, for monitoring the liquidation of outbreak foci and for other research purposes.

Simulating coconut growth, development and yield with the InfoCrop-coconut model

Simulation modeling of perennial crops has immense potential for generating information for plantation managers. We report the development of the InfoCrop-coconut model and its application to coconut (Cocos nucifera L.) growing in diverse tropical and subtropical environments. The model is based on the generic crop model InfoCrop that simulates various annual crops in tropical and subtropical regions. The InfoCrop-coconut model was calibrated and validated with data compiled from published studies comprising many physiological, agronomical and nutritional experiments conducted between 1978 and 2005 in diverse geographic locations throughout India. The treatments included various water and nutrient regimes and varieties of coconut. Time to first flowering varied between 4 and 6 years, leaf production varied from 8 to 15 leaves year(-1) and nut yield ranged from 3000 to 27,000 nuts ha(-1) year(-1). The genetic coefficients used for calibration and validation were generated from field experiments conducted during 1995-2005. Model efficiency and validation performance were analyzed statistically. Simulated trends in phenological development, total dry mass and its partitioning, and nut yield agreed closely with observed values, although a 15% error was observed in a few cases. Considering that field measurements have an experimental error of 10-15% and wide variation existed within treatments, the model adequately simulated the effects of management practices and agro-climatic conditions over short periods. For a range of agro-climatic zones, simulated potential yields varied from 26 to 30 Mg ha(-1) year(-1) and potential annual dry mass production varied from 52 to 62 Mg ha(-1), depending on environment. We conclude that InfoCrop-coconut can be used to increase the efficiency of agronomic experiments designed to aid coconut crop management.

Myxoid adrenal adenoma with focal pseudoglandular pattern

Adrenal cortical tumors with myxoid change are rare tumors. To our knowledge, only 22 cases have been described so far in literature, which include 13 carcinomas and 9 adenomas. A pseudoglandular pattern has been described in 9 of these tumors. We report a case of a myxoid adenoma of the left adrenal gland in a 67-year-old woman, with a focal pseudoglandular pattern involving about 20% of the studied tumor. Rest of the tumor was composed of anastomosing cords of tumor cells. Abundant myxoid stroma was present, which stained positively with alcian blue and was weakly focally positive with periodic acid Schiff. Immunophenotype was consistent with an adrenal tumor, i.e., positive for vimentin, inhibin, and melan A. Cytokeratin AE1/AE3 and chromogranin were negative. MIB-1 index was < 0.1%.

Finite element modelling of breast biomechanics: directly calculating the reference state

Patient-specific models of the biomechanics of the breast based on finite deformation theory is potentially a valuable tool to assist clinicians in assimilating and assessing information obtained from different views of the breast, under different loading conditions and using different imaging modalities. It is anticipated that a computational model of the large deformation mechanics of the breast will also improve the accuracy of non-rigid registration techniques by restricting the deformations imposed by the algorithm to be those which are physically plausible. Accurate registration will assist clinicians in tracking suspicious regions of tissue across multiple views of the breast, which are typically taken by applying different loads on the breast during imaging. For instance, a model that can predict deformations during mammography would help to track a region of tissue between a cranio-caudal (CC) view and a medio-lateral oblique (MLO) view. Due to the nonlinear deformations imposed on the breast during different imaging techniques, the finite element reference geometry from which deformations are predicted is important. Gravity loads act on the breast during all imaging modalities. In this paper, we describe a novel modification to solving the finite element implementation of finite deformation theory, which can predict the reference state of the breast from a deformed configuration that has been derived from images of a patient placed in a single known orientation with respect to the direction of gravity.

Serological evidence for wide distribution of spotted fevers & typhus fever in Tamil Nadu

BACKGROUND & OBJECTIVE

Although the re-emergence of spotted fevers and typhus was documented from southern India a few years ago, there was a paucity of community based data. Therefore a collaborative study was carried out in several districts of Tamil Nadu to understand the distribution of these infections.

METHODS

Blood (3 ml) was collected from patients presenting to primary health centres (PHCs) with fever >10 days duration in 15 districts of Tamil Nadu during January 2004 to December 2005. Patients negative for malaria, were tested by Weil-Felix test. Clinical data were collected from patients visiting two hospitals.

RESULTS

A total 306 samples were tested in 2004 and 115 (37.5%) had titres of >or=80 with OX K antigen, suggesting a diagnosis of scrub typhus. During 2005, 964 patients were tested and 89 (9.2%) were positive for scrub typhus. An additional 44 (4.6%) were positive for other rickettsial illnesses. In both years majority of scrub typhus occurred in individuals above 14 yr of age. Cases increased from August until the earlier part of next year.

INTERPRETATION & CONCLUSION

This community based study from south India involving several districts in Tamil Nadu, showed that scrub typhus and rickettsial illnesses were widely distributed in the State. Measures to increase awareness and also to diagnose and treat this infection in the affected areas are essential.

Finite Element Modelling of Breast Biomechanics: Finding a Reference aState

Non-rigid-body registration techniques, that constrain the set of possible soft tissue deformations to be consistent with the basic laws of physics, offer a means of providing realistic and accurate estimates of breast movement under mammographic compression. Such constraints can be imposed by the use of anatomically accurate finite element models that predict soft tissue deformations. The overarching aim is to develop tools for tracking regions of interest across multiple images (different views taken at different times) for image-guided surgeries and reliable diagnostic and therapy monitoring. Due to the nonlinear deformations imposed on the breast under the various imaging modalities, the finite element reference geometry from which deformations are predicted is important. Gravity loads act on the breast in all imaging modalities. In this paper, we propose a method of identifying a stress-free reference state of the breast given a series of loaded deformed configurations that have been derived from images of a patient placed in different orientations with respect to the direction of gravity.

Advances in the percutaneous treatment of aortic and mitral valve disease

The healthcare burden of valvular heart disease continues to increase as our population ages. Because of advances in operative techniques and cardiac anesthesiology, surgery has excellent safety and durability for many patients, and surgery remains the gold standard for treating valvular heart disease. Because many patients have comorbidities that increase operative risk, interest in catheter-based valve repair and replacement has grown. Early human experience with aortic stent-valve prostheses has been quite encouraging. For mitral regurgitation, percutaneous annuloplasty and leaflet repair are being developed by numerous companies, and early human studies have demonstrated feasibility of percutaneous repair. Continuing advances in technology and experience promise to expand the role of percutaneous repair and replacement in the treatment of valvular heart disease. Ongoing trials will help define long-term durability and safety, along with appropriate patient selection for percutaneous treatment.

A biomechanical model of mammographic compressions

A number of biomechanical models have been proposed to improve nonrigid registration techniques for multimodal breast image alignment. A deformable breast model may also be useful for overcoming difficulties in interpreting 2D X-ray projections (mammograms) of 3D volumes (breast tissues). If a deformable model could accurately predict the shape changes that breasts undergo during mammography, then the model could serve to localize suspicious masses (visible in mammograms) in the unloaded state, or in any other deformed state required for further investigations (such as biopsy or other medical imaging modalities). In this paper, we present a validation study that was conducted in order to develop a biomechanical model based on the well-established theory of continuum mechanics (finite elasticity theory with contact mechanics) and demonstrate its use for this application. Experimental studies using gel phantoms were conducted to test the accuracy in predicting mammographic-like deformations. The material properties of the gel phantom were estimated using a nonlinear optimization process, which minimized the errors between the experimental and the model-predicted surface data by adjusting the parameter associated with the neo-Hookean constitutive relation. Two compressions (the equivalent of cranio-caudal and medio-lateral mammograms) were performed on the phantom, and the corresponding deformations were recorded using a MRI scanner. Finite element simulations were performed to mimic the experiments using the estimated material properties with appropriate boundary conditions. The simulation results matched the experimental recordings of the deformed phantom, with a sub-millimeter root-mean-square error for each compression state. Having now validated our finite element model of breast compression, the next stage is to apply the model to clinical images.

Geographical information system (GIS) in investigation of an outbreak

An outbreak of fever in a village in southern India was reported on 1st September, 2001. The first reported case presented with epistaxis and a platelet count of 27000h(1)/mm3. Clinical, laboratory and entomological evidence supported a diagnosis of dengue fever. One third of the village was affected and 3.7 % of the population presented with haemorrhagic symptoms; none were fatal. Five acute cases tested for dengue specific IgM showed that two were positive. The larvae of Aedes aegypti were discovered from domestic water collections in the village. Spatial analysis done with the help of Geographical Information Systems software (GIS) demonstrated a centrifugal spread of cases from the most affected street until it involved the entire village. Spatial analysis revealed that cases occurred in clusters and that these could not have occurred by chance. This was our first experience in producing a geo-referenced map of a village area and in spatial analysis. GIS is a novel and simple tool for outbreak investigations and the spatial analyst adds additional information to the data collected. Control of adult mosquitoes and larvae prevented the outbreak from spreading to an adjacent village.

An outbreak of human anthrax in Mysore (India)

Anthrax is a zoonotic disease caused by Bacillus anthracis. Intestinal anthrax though a rare entity mostly ends with fatal outcome. Very few cases of intestinal anthrax are reported. Present outbreak of intestinal anthrax is unique in itself that four cases succumbed to the illness within a span of 48-72 hours in a small hamlet of Mysore district of Karnataka, after consuming diseased deer meat. Confirmation of the diagnosis was carried out at NICD, Delhi by bacteriological culture isolation, biochemical tests, animal pathogenicity and polymerase chain reaction (PCR). This outbreak clearly indicates surveillance of anthrax in animals in endemic areas is an essential part in the control of the disease with intersectoral coordination between the departments of health, animal husbandary, agriculture and forest.

Latex agglutination test in the diagnosis of pyogenic meningitis

Samples of cerebrospinal fluid (n=204) from pediatric patients with clinically suspected pyogenic meningitis were examined by direct microscopy, bacterial culture and Latex Agglutination Test (LAT). Latex Agglutination Test was done for detection of antigen of Streptococcus pneumoniae and Haemophilus influenzae type b. Among 38 LAT positive cases, culture and/or gram stain was positive in only 20 cases and 18 cases were detected exclusively by LAT. Besides, LAT was useful in detecting the pre-treated cases as 11 out of 55 samples from pre-treated cases were positive by LAT in comparison to culture and/or Gram stain which detected only 4 of 55 cases. LAT is simple, rapid and more reliable test.

Surgical management of cirsoid aneurysms

BACKGROUND

Cirsoid aneurysms (arteriovenous fistulas) of the scalp are rare lesions. They are infrequently encountered in neurosurgical practice. These lesions are difficult to manage because of their complex vascular anatomy, high shunt flow and cosmetic disfigurement. We report our experience in the surgical management of these lesions.

METHODS

We treated 11 patients with cirsoid aneurysms surgically. All except one patient were males who were in the second and third decades of life. History of trauma was present in 6 patients. In one patient, the lesion had been present since birth. Occipital and frontal regions were the sites commonly involved. Superficial temporal, occipital and posterior auricular arteries were the most frequent feeding arteries. The size ranged from 3 cms to 12 cms. Following investigations were done: CT, MRI, MRA, angiography and Doppler studies.

FINDINGS

Excision of the lesion was done in 8 patients and en bloc resection of the lesion with the scalp with reconstruction was done in the remaining three. One among the three patients who underwent en bloc resection had undergone prior surgery. None of the patients underwent preoperative endovascular treatment. One patient had undergone intralesional injection of sclerosing agents twice. Superficial scalp necrosis occurred in two patients but was treated successfully. All the patients except one had good cosmetic results and there was no recurrence during an average follow up of 18 months.

INTERPRETATION

Surgical excision with good cosmetic results is feasible in patients with cirsoid aneurysms.

A study of dermatophytes and their in-vitro antifungal sensitivity

Of the 150 clinically suspected cases of Dermatophytosis studied, majority of the cases were from age group 11-20 and 21-30 (51.4%), Tinea corporis (48.7%) and Tinea capitis (18%) were the commonest clinical types. The isolation rate was 24% (36) of which 19 (52.7%) were Trichophyton rubrum, 11 (30.55%) were Trichophyton mentagrophytes and 4 (11.1%) were Trichophyton violaceum. One isolate each of Microsporum gypseum & Epidermophyton floccosum were obtained. Griseofulvin proved to be the best drug with a sensitivity of 94.4% followed by Miconazole (75% sensitive). Tolnaftate showed a sensitivity of 47.22%. For Clotrimazole only 30.55% of the isolates were sensitive.

Rapid diagnosis of cholera by coagglutination test

In this study the coagglutination test for the rapid diagnosis of cholera is evaluated in comparison with the conventional culture method. A total of 553 stool specimens were processed from cases of acute gastro-enteritis. The sensitivity and specificity of coagglutination test was 92.77% and 95.65% respectively. The coagglutination test is found to be simple, reliable and rapid method for the diagnosis of cholera.

Serotypes and phage types of Vibrio cholerae in Mysore

A total of 565 samples of acute diarrhoeal stools from children received over a period of twelve months from November 1996 to October 1997, yielded 289 (51.15%) isolates of V. cholerae. Out of these, 277 (95.85%) were V. cholerae 01 serotype Ogawa, 7 (2.42%) were V. cholerae 0139 and 5 (1.73%) were V. cholerae non-O1 non-0139. Phage typing of the isolates was carried out by NICED Calcutta. Out of 78 isolates, 69 (88.46%) belong to phage type T27. Of the remaining, 3 (3.85%), 3(3.85%), 2(2.56%) and 1(1.28%) belong to the phage types T26, T13, T8 and T4 respectively.

Recombinant toxins that bind to the urokinase receptor are cytotoxic without requiring binding to the alpha(2)-macroglobulin receptor

The alpha(2-)macroglobulin receptor (alpha(2)MR) has been reported to mediate the internalization of the urokinase plasminogen activator receptor (uPAR) via ligand binding to both receptors. To target malignant uPAR-expressing cells and to determine whether uPAR can internalize without ligand binding to alpha(2)MR, we engineered two recombinant toxins, ATF-PE38 and ATF-PE38KDEL. Each consists of the amino-terminal fragment (ATF) of human urokinase and a truncated form of Pseudomonas exotoxin (PE) devoid of domain Ia, which binds alpha(2)MR. ATF-PE38 and ATF-PE38KDEL were cytotoxic toward malignant uPAR-bearing cells, with IC(50) values as low as 0.02 ng/ml (0.3 pM). Cytotoxicity could be blocked using either recombinant urokinase or free ATF, indicating that the cytotoxicity of the recombinant toxins was specific. Radiolabeled ATF-PE38 had high affinity for uPAR (K(d) = 0.4-8 nM) on a variety of different malignant cell types and internalized at a rate similar to that of ATF. The cytotoxicity was not diminished by receptor-associated protein, which binds and shields the alpha(2)MR from other proteins, or by incubation with phorbol myristate acetate, which is known to decrease the number of alpha(2)MRs in U937 cells or by antibodies to alpha(2)MR. Therefore, these recombinant toxins appear to internalize via uPAR without association with the alpha(2)MR.

Similarities in the biodistribution of iodine-labeled anti-Tac single-chain disulfide-stabilized Fv fragment and anti-Tac disulfide-stabilized Fv fragment

We evaluated the biodistribution and pharmacokinetics of two different iodine-labeled Fv fragments of anti-Tac monoclonal antibody (MAb) in normal and tumor-bearing nude mice. One was a disulfide-stabilized Fv fragment (dsFv), and the other was a single-chain disulfide-stabilized Fv fragment (scdsFv). The scdsFv is a newly developed type of Fv fragment superior to the dsFv in which the VH and VL are linked by covalent bonds through a spacer arm and by an internal disulfide bond. These modifications increase the yield of scdsFv. Both reagents recognize the alpha subunit of the interleukin-2 receptor (IL-2Ralpha). The biodistribution of the Fv fragments was evaluated in normal mice co-injected with 50 mg of L-lysine and in a no-lysine control group. Biodistribution was also evaluated in nude mice bearing subcutaneous tumor xenografts derived from IL-2Ralpha-positive ATAC4 cells and receptor-negative A431 cells. These mice were co-injected with 125I-labeled anti-Tac scdsFv (6 microCi/0.7 microg) and 131I-labeled anti-Tac dsFv (2 microCi/0.7 microg) or with 131I-labeled anti-Tac scdsFv (6 microCi/0.7 microg) and 125I-labeled anti-Tac dsFv (4 microCi/0.7 microg). The biodistribution of 125I-labeled anti-Tac scdsFv and 131I-labeled anti-Tac dsFv was very similar in all organs and the tumors. The renal uptake of both reagents was blocked effectively (<93%) and similarly by lysine. The scdsFv cleared slightly faster from the circulation than did the dsFv because there were more aggregates of dsFv than of scdsFv (3% vs. 1%, respectively). The scdsFv-to-dsFv ratio ranged from 0.79 to 1.20 in all organs at all time points we examined. In conclusion, the first biodistribution study of an scdsFv molecule shows that the scdsFv had a biodistribution very similar to that of the dsFv and seems to be a good alternative to the dsFv because of its higher production yield.

A form of anti-Tac(Fv) which is both single-chain and disulfide stabilized: comparison with its single-chain and disulfide-stabilized homologs

Disulfide-stabilized Fvs (dsFvs) are recombinant proteins composed of a heavy-chain variable domain (VH) of an antibody connected via a disulfide bond to the light-chain variable domain (VL). In single-chain Fvs (scFvs), a peptide connector links VH and VL. The dsFv form of the anti-Tac monoclonal antibody which reacts with the alpha subunit of the IL2 receptor was recently reported to be more stable and to aggregate less during renaturation than anti-Tac(scFv). In addition, it could be produced in a better yield owing to less aggregation. However, the yields are still too low to permit the production of material for clinical trials in which the dsFv will be used to image or treat IL2 receptor (CD25)-containing tumors. To increase the efficiency by which VH and VL associate and form a disulfide bond during renaturation, we have prepared an Fv form of anti-Tac which is both single chain and disulfide stabilized (scdsFv). The recombinant protein is expressed in Escherichia coli, where it accumulates in inclusion bodies. Using inclusion body protein as the reference point, the yield of purified anti-Tac(scdsFv) was 13% compared with 2% for anti-Tac(dsFv). Anti-Tac(scdsFv) has equivalent binding affinity, immunoreactivity after radiolabeling and stability. The results show that a linker between VH and VL facilitates heterodimer formation and leads to disulfide bond formation in a higher percentage of the molecules renatured. Thus anti-Tac(scdsFv) is the preferred form of anti-Tac(Fv) to be used for clinical studies. We anticipate that scdsFvs will be the optimum recombinant form of Fv to produce from bacteria.

Mobile extracorporeal shockwave lithotripsy

During the last 18 months, extracorporeal shockwave lithotripsy (ESWL) has been provided at Epsom District Hospital using a mobile unit containing a Dornier HM4 lithotriptor. Patients with upper ureteric and renal stones were selected for treatment, which was performed without anaesthesia or sedation as a day-case procedure; 83 patients were treated, 5 of them with bilateral stones. Seventy patients required 1 treatment session, 17 required 2 and 1 patient required 3. There were no serious complications but 3 patients needed ureteroscopy to remove obstructing stones. The overall success rate was 86%. The cost to treat each NHS patient was 253 pounds. Mobile lithotripsy as a day-case procedure is a safe and cost-effective means of treating urolithiasis and can be performed in a District General Hospital.

Strictures of the penile urethra

One hundred and eighty-seven patients with urethral strictures have been treated over a period of 2 1/2 years. In nearly 50%, strictures were confined to the penile urethra, involving the meatus, the fossa navicularis or varying lengths of the urethra up to the bulb. Of these, 95.3% were inflammatory in nature. Overall, 85.5% were managed with a single surgical procedure. The single-stage technique using a skin inversion pedicled flap was done in 15 cases and was found to be useful, with less morbidity than the staged procedure.

Does abscisic acid influence proline accumulation in stressed leaves?

Root treatments of barley (Hordeum distichum L.) plants with 10(-7) to 10(-4) M abscisic acid (ABA) caused an increase in proline content, especially at higher concentrations, within 2-3 h. Even 3 h after the removal of ABA from the medium the plants continued to accumulate proline. The higher the concentration of the ABA, the higher was the proline level at 6 h. When the highest ABA concentration, 10(-4) M, was tested with polyethylene glycol (PEG) (-5.0 bars) in the medium, the ABA treatment resulted in a higher proline content than in control plants. The treatments "PEG alone" and "PEG + ABA" resulted in heavy accumulation of proline, especially, 3 h after releasing the plants from the stress. The proline content in PEG+ABA-treated plants was always higher than plants treated with PGE or ABA alone. In peas (Pisum sativum L. cv Alaska) the same trend occurred although to a lesser degree. These findings indicate an influence of ABA on proline accumulation in water-stressed plants.