Collaboration between the military and a charity: delivering care to patients, training to defence medical staff and defence engagement overseas

The Royal College of Anaesthetists Military Anaesthesia higher training module was approved in 2008. The opportunities for trainee deployments to operational environments are limited, and while the need to ensure training and demonstrate the unique military skill set remains, these may not be consistently attainable within NHS posts. This paper proposes a template for the successful integration of military training with a charity mission by describing experiences in Addis Ababa over the two weeks of Project Harar's 2020 Complex Surgery Mission. This model not only benefits patients and military trainees by providing opportunities to gain the skills and attributes required by the Armed Services Consultant Appointment Board, but also by projecting the Defence Medical Services on the global stage.

Optimizing a therapeutic humanized follicle-stimulating hormone-blocking antibody formulation by protein thermal shift assay

Biopharmaceutical products are formulated using several Food and Drug Administration (FDA) approved excipients within the inactive ingredient limit to maintain their storage stability and shelf life. Here, we have screened and optimized different sets of excipient combinations to yield a thermally stable formulation for the humanized follicle-stimulating hormone (FSH)-blocking antibody, MS-Hu6. We used a protein thermal shift assay in which rising temperatures resulted in the maximal unfolding of the protein at the melting temperature (T_m ). To determine the buffer and pH for a stable solution, four different buffers with a pH range from 3 to 8 were screened. This resulted in maximal T_m s at pH 5.62 for Fab in phosphate buffer and at pH 6.85 for Fc in histidine buffer. Upon testing a range of salt concentrations, MS-Hu6 was found to be more stable at lower concentrations, likely due to reduced hydrophobic effects. Molecular dynamics simulations revealed a higher root-mean-square deviation with 1 mM than with 100 mM salt, indicating enhanced stability, as noted experimentally. Among the stabilizers tested, Tween 20 was found to yield the highest T_m and reversed the salt effect. Among several polyols/sugars, trehalose and sucrose were found to produce higher thermal stabilities. Finally, binding of recombinant human FSH to MS-Hu6 in a final formulation (20 mM phosphate buffer, 1 mM NaCl, 0.001% w/v Tween 20, and 260 mM trehalose) resulted in a thermal shift (increase in T_m ) for the Fab, but expectedly not in the Fc domain. Given that we used a low dose of MS-Hu6 (1 μM), the next challenge would be to determine whether 100-fold higher, industry-standard concentrations are equally stable.

FSH-blocking therapeutic for osteoporosis

Pharmacological and genetic studies over the past decade have established the follicle-stimulating hormone (FSH) as an actionable target for diseases affecting millions, namely osteoporosis, obesity, and Alzheimer's disease. Blocking FSH action prevents bone loss, fat gain and neurodegeneration in mice. We recently developed a first-in-class, humanized, epitope-specific FSH-blocking antibody, MS-Hu6, with a K_D of 7.52 nM. Using a GLP-compliant platform, we now report the efficacy of MS-Hu6 in preventing and treating osteoporosis in mice and parameters of acute safety in monkeys. Biodistribution studies using ⁸⁹Zr-labelled, biotinylated or unconjugated MS-Hu6 in mice and monkeys showed localization to bone and bone marrow. MS-Hu6 displayed a β phase t_½ of 7.5 days (180 hours) in humanized Tg32 mice. We tested 217 variations of excipients using the protein thermal shift assay to generate a final formulation that rendered MS-Hu6 stable in solution upon freeze-thaw and at different temperatures, with minimal aggregation, and without self-, cross-, or hydrophobic interactions or appreciable binding to relevant human antigens. MS-Hu6 showed the same level of 'humanness' as human IgG1 in silico and was non-immunogenic in ELISPOT assays for IL-2 and IFNg in human peripheral blood mononuclear cell cultures. We conclude that MS-Hu6 is efficacious, durable, and manufacturable, and is therefore poised for future human testing.

An electron holography study of perpendicular magnetic tunnel junctions nanostructured by deposition on pre-patterned conducting pillars

The fabrication of multi-gigabit magnetic random access memory (MRAM) chips requires the patterning of magnetic tunnel junctions at very small dimensions (sub-30 nm) and a very dense pitch. This remains a challenge due to the difficulty in etching magnetic tunnel junction stacks. We previously proposed a strategy to circumvent this problem by depositing the magnetic tunnel junction material on prepatterned metallic pillars, resulting in the junction being naturally shaped during deposition. Upon electrical contact, the deposit on top of the pillars constitutes the magnetic storage element of the memory cell. However, in this process, the magnetic material is also deposited in the trenches between the pillars that might affect the memory cell behaviour. Here we study the magnetic interactions between the deposit on top of the pillars and in the trenches by electron holography, at room temperature and up to 325 °C. Supported by models, we show that the additional material in the trenches is not perturbing the working principle of the memory chip and can even play the role of a flux absorber which reduces the crosstalk between neighboring dots. Besides, in the studied sample, the magnetization of the 1.4 nm thick storage layer of the dots is found to switch from out-of-plane to an in-plane configuration above 125 °C, but gradually decreases with temperature. Electron holography is shown to constitute a very efficient tool for characterizing the micromagnetic configuration of the storage layer in MRAM cells.

The Role of Biomarkers for the Prediction of Response to Checkpoint Immunotherapy and the Rationale for the Use of Checkpoint Immunotherapy in Cervical Cancer

Checkpoint immunotherapy has revolutionised the way that melanoma is treated and has also shown significant effectiveness in lung, bladder, renal, and head and neck cancers. At the present time, trials of checkpoint immunotherapy in cervical cancer are at early phases, but there is very good rationale for pursuing this as a treatment option, especially as cervical cancer is a virally driven cancer and therefore should be recognised by the immune system as being foreign. This review explores the biomarkers for the selection of patients for immunotherapy in other cancers, such as programmed death ligand 1 (PD-L1) expression, tumour infiltrating lymphocytes and total mutational burden, and relates these biomarkers to cervical cancer. A PubMed search was carried out for publications published in English with the terms 'immunotherapy' OR 'cervical cancer' OR 'checkpoint blockade' OR 'tumour infiltrating lymphocytes' OR 'total mutational burden'. Articles that met these criteria and were available on PubMed before 8 October 2018 were included. The results showed that PD-L1 is positive in up to 90% of cervical cancers and that the total mutational burden is moderately high, with 5-6 mutations per megabase. In addition, the tumour microenvironment in cervical cancer has an impact on prognosis, with higher ratios of CD8+ tumour infiltrating lymphocytes to CD4+ T regulatory cells being associated with improved survival. Clinical studies to date have shown the response rate of cervical cancer to checkpoint immunotherapy to be in the region to 10-25%. Cervical cancer exhibits many of the features that have been shown to be correlated with response to checkpoint immunotherapy in other tumour sites. However, response rates to date are in the region of 10-25%. Therefore, combinations of immunotherapeutic agents or checkpoint inhibitors with radiotherapy may be required to maximise the therapeutic benefit of harnessing the host immune system to fight cancer.

Combinatorial Characterization of Saliva for Oral Precancer Diagnostics

Background: Saliva based diagnostic can play an important role in the translational research related to cancer diagnostics and treatment. It is easily available, noninvasive, low storage cost, has less contamination chances with simple collection procedure. Cancers related to tobacco use, including oral cancer account for about 30% of all cancers in males and females. Five years' survival rate remains the same even after decades of advancement of detection, prevention, and treatment of OSCC (oral squamous cell carcinoma) mainly due to late diagnosis of oral potentially malignant disorders (OPMDs). Aim: Combinatorial characterization of saliva, endorsing multidimensional spectroscopic signatures using suitably designed biochamber. Methods: Eighteen saliva samples (6 normal, 6 OSF [oral submucous fibrosis, a type of OPMD] and 6 confirmed OSCC) were collected from GNIDSR (Guru Nanak Institute of Dental Science and Research) Kolkata. Ethical approval was obtained for the study and all the participants were explained the objectives of the study and a written informed consent was obtained from them. Participant's demographic detail and clinical characteristics were also recorded. The participants were asked not to consume food 1 hour before sample collection and were suggested to rinse their mouth 30 minutes prior to saliva expectoration to minimize the contamination of food in saliva. Empty, sterile, graded tubes were used for this purpose. The subjects were asked not to clear nose or throat during the process of saliva expectoration to avoid forced phlegm from other part of the respiratory tract. The saliva samples were then immediately transferred to −20 degrees and later in −80 degrees for long storage. The electrical impedance (EI) of saliva was measured in custom made biochambers with copper electrodes. The EI was measured for the frequency sweep from 20 Hz to 2 MHz using an impedance analyzer. Apart from EI measurement, the corresponding samples were subjected to FTIR (Fourier-transform IR spectroscopy) analysis. SPSS and OMNIC software were used for the data analysis of EI and FTIR respectively. Results: [Table: see text][Table: see text][Table: see text][ Table A , B & C represents descriptive statistics, correlation matrix and component matrix respectively. The multivariate analysis of the FTIR data indicates the significant differences ( P < 0.005) among the different study groups such as normal, OSF and OSCC. The eigen values (normal 0.917, OSF 0.962, OSCC 0.975) from component matrix analysis also indicate the same. Conclusion: The spectroscopic characterization (EI and FTIR) of saliva was effective in evaluating normal and OPMD condition. This noninvasive paradigm can serve as a complimentary technique to the existing gold standard methods for the early detection of oral cancer.

Epithelial mesenchymal transition in lung cancer cells: A quantitative analysis

Cellular auto-fluorescence along with morphological and cytoskeletal features were assessed in lung cancer cells undergoing induced epithelial mesenchymal transition (EMT). During EMT progression, significant increase was observed in cellular aspect ratio (AR), filamentous (F)-actin and green auto-fluorescence intensities while blue intensity decreased. These features were provided to a kernel classification framework. The classification accuracy were impressive, thus these features along with the classification technique can be considered as suitable tools for automated grading of lung cancer cells undergoing EMT progression.

The role of cytology and other prognostic factors in endometrial cancer

The clinical and prognostic value of positive cytology in women with endometrial cancer remains uncertain. The aim of our retrospective observational study was to determine whether in women with disease confined to the uterus, positive peritoneal cytology adversely affects disease-free (DFS) or overall survival (OS); to assess whether positive or negative cytology affects survival in women irrespective of stage and to assess whether the use of hysteroscopy or Pipelle for diagnosis affected cytology positivity rates. We have shown that median DFS and OS were almost identical for tumours confined to the uterus with and without positive peritoneal cytology. Women with tumours extending to the serosa or adnexa had a non-statistically significant shorter survival in comparison with women with stage I disease and negative cytology. Out of 59 women that had their cancer diagnosis based on a Pipelle biopsy of the endometrium, five had positive peritoneal washings. A total of 150 women had pre-treatment hysteroscopy; seven of these had positive peritoneal washings. There was no significant difference in the rates of positive cytology between these groups (4.6% vs 8.4%). In our cohort of un-staged women, positive peritoneal cytology did not adversely affect prognosis when disease was confined to the uterus.

Personal professional indemnity and contractual issues for trainees in obstetrics and gynaecology

Over the last few decades, more healthcare professionals have faced investigation into complaints about medical care and healthcare outcomes (Department of Health 2003). With increasing medical negligence cases being brought against doctors, it is time to carefully consider the implications of such actions to ensure appropriate safeguards (Ferner and McDowell 2006). At a time when the culture of 'no win, no fee' is rampant, the jobbing frontline doctor is on the back-foot trying to untangle the legalities of a malpractice claim (Ferner and McDowell 2006). Reassuringly, the numbers of doctors referred to the GMC or having to face legal procedures or claims for compensation are still very small (National Audit Office 2001). An essential issue for all doctors is having appropriate indemnity cover in the event that their practice is challenged. The opt-out for the European Working Time Regulations (EWTR) has caused further confusion as to what is covered for junior doctors by individual indemnity policies and the employer's liability scheme. Recently, the RCOG Trainees committee and the BMA Junior Doctors Association issued a joint advice regarding this issue (RCOG 2010). In this paper, we consider the differences in cover provided by the employer's liability scheme, individual professional indemnity schemes and the role of professional bodies. We also seek to clarify the understanding of these surrounding EWTR and the voluntary opt-out clause and provide up-to-date information on medico-legal issues and protection schemes regarding legal liabilities.

Training the trainees: an evaluation exercise using the TLH and BSO model

Our aim was to evaluate surgical training in gynaecological oncology by assessing the time required by a trainee to complete a single laparoscopic gynaecologic-oncological operation. A total of 135 patients with a BMI < 40 kg/m2, diagnosed with endometrial cancer, underwent a total laparoscopic hysterectomy and bilateral salpingo-oophorectomy (TLH and BSO). Patients in Group I (n = 78) were operated on by a consultant gynaecological oncology surgeon and in Group II (n = 57) by sub-specialist trainees (SSTs). The mean patient age and BMI was 63.5 years and 29.6 kg/m2, respectively, in Group I and 64.5 years and 29.9 kg/m2, respectively, in Group II. Median operating times for Groups I and II were 58 and 90 min, respectively (p < 0.05). Furthermore, significant improvement was noted when comparing the average operating time between the first and second half of SST training. Even experienced gynaecological trainees take significantly longer to perform a reproducible laparoscopic operation. At the completion of training, an SST demonstrates improvement with respect to operation duration but is still not as fast as the trainer.

Microtrap electrode devices for single cell trapping and impedance measurement

This paper reports the design and fabrication of electrode microtraps for single cell trapping and impedance measurement. In this work, the microtrap electrodes of parallel and elliptical geometry have been fabricated by electroplating of gold electrodes of optimum thickness. This has enabled the formation of electrode traps without requiring any precision alignment between separate insulating traps like PDMS and the bottom gold electrodes. Further the improved uniformity of the electric field between the trapping electrodes as observed from COVENTORWARE simulation significantly reduces the effect of cell position inside the microwell on the electrical measurement unlike previous reports. This makes it possible to directly extract the equivalent cell parameters from the electrical measurement without introducing any correction factor corresponding to cell position. We have performed impedance spectroscopy with both the microwell electrode structures with single HeLa cell at two different positions of trapping. It has been observed that there is almost no change in the extracted values of cell resistance and capacitance for different positions within parallel electrodes and there is only 0.7 % and 0.85 % change in cell resistance and capacitance for the two positions within elliptical electrodes. Thus these microwell electrode structures can be used as an improved and a more convenient platform for single cell electrical characterization.

A novel wavelet neural network based pathological stage detection technique for an oral precancerous condition

AIM

To describe a novel neural network based oral precancer (oral submucous fibrosis; OSF) stage detection method.

METHOD

The wavelet coefficients of transmission electron microscopy images of collagen fibres from normal oral submucosa and OSF tissues were used to choose the feature vector which, in turn, was used to train the artificial neural network.

RESULTS

The trained network was able to classify normal and oral precancer stages (less advanced and advanced) after obtaining the image as an input.

CONCLUSIONS

The results obtained from this proposed technique were promising and suggest that with further optimisation this method could be used to detect and stage OSF, and could be adapted for other conditions.

Excess chromium alters uptake and translocation of certain nutrients in citrullus

Citrullus plants were grown in refined sand with varying levels of chromium to determine their tolerance limit to excess chromium. The plants were maintained in control nutrient solution for 24 days and on the 25th day chromium as dichromate was added at 0.05, 0.1, 0.2, 0.3 and 0.4 mM. A control set of plants was grown in the same nutrient solution without chromium. At chromium levels >0.2 mM plants showed growth depression, with chlorosis and loss of turgor of middle leaves. Affected leaves had narrow lamina; tendrils were thin, short and did not have coiling property. Later chlorosis became severe and changed to necrosis in patches. Petiole along with lamina became wilted, rugged and hung down due to complete loss of water. At lower chromium concentration, (0.05, 0.1 and 0.2 mM) only depression in growth was observed. With increase in chromium concentration of nutrient solution accumulation of chromium in different parts of Citrullus was increased. Increase in concentrations of phosphorus, manganese and decrease in iron, copper, zinc and sulphur were observed in leaves. Toxicity of chromium was greater at 0.2-0.4 mM, compared to lower concentrations. Threshold of toxicity and toxicity of Cr in old leaves were, respectively, 0.9 and 3.9 microg g(-1) dry matter of citrullus.

Historical introduction of acupuncture in India

Acupuncture, though originated in oriental countries in the ancient times but, its philosophical understanding is amazingly wide open to the modern medical science. Historically, records are there regarding its Indian origin. However, acupuncture practised today in Indian sub-continent mainly shows Chinese origin and its introduction to India was pioneered by Dr. B.K. Basu, the first Indian who learned Chinese acupuncture from mainland China during 1959. It is interesting enough to note that though acupuncture is successfully practised in India in a rejuvenated form for the last few decades but due to lack of proper Governmental support this thereby suffers from under utilization and under development. While WHO suggested for its wider application and development through concerted Governmental efforts.

Primary malignant giant cell tumour of bone--a study of two cases with short review

Primary malignant giant cell tumour of bone is extremely rare. It is distinctly separate from benign metastasising giant cell tumour of bone and secondary malignant giant cell tumour which occurs in response to radiotherapy and repeated curettage of benign giant cell tumor. The tumor has high mortality rate. It usually affects lower end of femur and upper end of tibia. Two usually affects lower end of femur and upper end of tibia. Two cases, on involving upper end of tibia and other in vertebra are discussed. Extreme paucity of literature prompted to publish this article. A short review of radiological appearance, histopathological findings and treatment modalities is highlighted.

Phytotoxicity of cobalt, chromium and copper in cauliflower

Cauliflower (Brassica oleracea L. var. Botrytis cv. Maghi) was grown in refined sand with complete nutrition (control) and at 0.5 mM each of Co, Cr and Cu. In cauliflower, compared to that of excess Cu or Cr, the visible effects of excess Co appeared first and were most pronounced. Excess of each heavy metal restricted the biomass of cauliflower, concentrations of Fe, chlorophylls a and b, protein and activity of catalase in leaves in the order Co>Cu>Cr. The translocation of Cr from roots to tops was minimum and that of Co was maximum when cauliflower was individually supplied with excess Co, Cu or Cr. In cauliflower each heavy metal inhibited the concentration of most of the macro- and micronutrients. The translocation of P, S, Mn, Zn and Cu from roots to tops of cauliflower were affected most significantly by Co and least by Cr. In contrast to excess Cu or Cr, Co significantly decreased the water potential and transpiration rates and increased diffusive resistance and relative water content in leaves of cauliflower.

Ultrastructural and trace metal studies on radiographers' hair and nails

Scalp hair and fingernail samples of 42 medical radiographers and 42 nonradiographers (control) with matching age groups and food habits were collected for this study. Trace metal estimation by atomic absorption spectrometry (AAS) has indicated a significant increase (P < 0.001) in Zn, Cu, and Cd contents in the radiographers' hair and nails. Scanning electron microscopy (SEM) revealed structural changes in the hair and nails of radiographers. Significant alterations in the Zn and Cd contents along with extensive structural damage in the hair and nails probably indicate that low-dose X-radiation imposes stress on these radiation workers.

A trace metal (zinc and iron) study on low dose x-radiation response in rat skin

There is no reliable bio-dosimeter regarding low dose radiation effects in mammalian systems. In this study, chronic low dose (< 1 cGy) whole body x-irradiated rat skin have shown altered trace metal (zinc and iron) content which clearly indicated the redistribution of these metals in the integumentary system. The decreased zinc to iron ratios suggested enhanced oxidative stress of the tissue. Changes in trace metal content in irradiated rat skin, as a biological response to low dose radiation, were non-linear. Moreover, the lowered zinc content of E2, E3, E4 and E5 dose groups suggested a different steady state, compared to the control. The Zn: Fe ratio decreased with increasing radiation dose.

Hepatotoxicity of diazepam. Structural and trace metal studies in rat

Studies of effects of diazepam on liver parenchyma are very scanty. In this study, adult albino rats were treated with diazepam in two different doses (0.25 mg and 0.30 mg/kg body wt) daily for 30 and 60 d. Through light microscopy and electron microscopy, prenecrotic and necrotic changes were noted in the high-dose group. Trace metal analysis indicated that zinc (Zn) was reduced by 30 and 60 day under both the doses, whereas iron (Fe) and copper (Cu) were reduced significantly in these groups only after 60 d of treatment. This reduction in metal contents may have some correlations with necrotic changes in liver parenchyma.

Zinc and iron as bioindicators of precancerous nature of oral submucous fibrosis

Oral Submucous Fibrosis (OSF) is a precancerous condition of oral cavity and oropharynx. Its etiopathogenesis is still obscure. Epithelial dysplasia is considered an important indicator of it. In the present study, the authors try to ascertain bioinorganic parameters as alternate indicators of malignant potential of OSF along with other clinicopathological attributes. They also try to identify causative factors. Thirty-six OSF patients, showing different degrees of epithelial dysplasia, and 12 normal individuals are studied with special reference to trace metal contents (Zn and Fe) in oral tissues. Statistical analyses of data indicate that trace metal contents can be regarded as an alternate indicator of the precancerous nature of OSF. Some clinicopathological attributes that are easier and cheaper to measure may also indicate OSF.

Autoregulation of luxR: the Vibrio harveyi lux-operon activator functions as a repressor

Mobility-shift assays have been used to demonstrate that the activator of the Vibrio harveyi lux operon, LuxR, binds independently, and with similar affinity, to two sites upstream of its own open reading frame. One site was located between 52 and 107 bp upstream of, and the other site in a region 25 bp downstream of, the transcriptional start site. The luxR promoter, in a transcriptional fusion with the chloramphenicol acetyl transferase (cat) gene, could readily be expressed in Escherichia coli as well as V. harveyi in the absence of LuxR. In both species, the presence of the luxR gene product resulted in repression of luxR promotion. These results show that LuxR directly regulates its own expression by functioning as an autorepressor. A mechanism for this repression is suggested by evidence showing that LuxR has a negative effect on RNA polymerase binding to the luxR promoter. In light of the fact that LuxR is also part of a regulatory family of repressors, the mechanism by which LuxR functions as a transcriptional activator of the lux operon has been re-examined.

The role of lux autoinducer in regulating luminescence in Vibrio harveyi; control of luxR expression

Analysis of Vibrio harveyi dark autoinducer mutants has demonstrated that the level of LuxR was much lower than that observed in wild-type cells. Complementation with luxR fully restored luminescence suggesting that the lux autoinducer may control expression of the luxR regulatory gene. By primer extension, the transcriptional start site of luxR was located 78 bp from the initiation codon. The level of the primer-extended product was enhanced upon addition of the lux autoinducer to the autoinducer mutants, which was confirmed by hybridization of lux mRNA with specific probes. By using chloramphenicol acetyltransferase as a reporter gene in a transcriptional fusion with luxR, the stimulatory effect of autoinducer on luxR expression was shown to occur at the level of the luxR promoter. The results provide evidence that the autoinducer signal in V. harveyi can be transduced through luxR, resulting in stimulation of luminescence.

Low-level X-ray exposures on rat skin. Hyperkeratinization and concomitant changes in biometal concentration

Integumentary structures naturally are more exposed to solar radiation than other body tissues, so there is a big question regarding the biological threshold of skin in respect to low-dose ionizing radiation. In this study, adult male albino rats were exposed chronically to low-dose (0.015 cGy/sec) X-rays for 9 and 18 mo, with total X-ray dose of 2.025 and 4.050 cGy, respectively. In both the dose groups, hyperkeratinization was noted in skin by transmission electron microscopic (TEM) study. Atomic absorption spectrometric (AAS) study revealed decreased zinc concentration (p < 0.01), increased iron concentration (p < 0.001), and status quo cadmium concentration. Moreover, the ratio between zinc and iron became highly depleted in both the irradiated groups. Hence it may be stated that chronic low-level X-rays induce redistribution of biometals in the skin. Nevertheless, specific concentrations of biometals indicate the risk-prone status of irradiated skin.

Trace metal levels of X-ray technicians' blood and hair

Medical X-ray technicians are exposed to low-level ionizing radiation in their occupational field. There are very few data on low-dose radiation effects. The present study was designed to estimate few vital trace metals (Zn, Cu, Fe) in indicator tissues (blood and hair) of X-ray technicians and non-X-ray technicians (hospital employees were used as controls) by Atomic Absorption Spectrometry (AAS). This analysis noted a significant increase in Zn, Cu, and Fe concentrations in X-ray technicians' hair. But in blood, Zn and Cu were depleted, whereas Fe was increased. Such changes in trace metal concentrations among X-ray technicians were noted where occupational exposure to radiation was for longer than three years. Through composite risk analysis, by using Zn:Fe as an indicator, it was noted that blood gave a stronger indication than hair in analyzing and estimating risk.

99Tcm-cystine, a renal function and imaging agent: a comparative study in dog with 131I-hippurate and 99Tcm-glucoheptonate to evaluate its functional and imaging characteristics

99Tcm-cystine, which has been proposed as a renal radiopharmaceutical for evaluating renal morphology and function in a single experiment, is compared with 131I-orthoiodohippurate (OIH) with respect to its renal clearance and extraction parameters and with 99Tcm-glucoheptonate (GHA) regarding its imaging characteristics. In spite of its comparable renal accumulation with 131I-OIH, its clearance (10.1 +/- 1.0 ml min-1 kg-1) was lower than that of 131I-OIH (21.5 +/- 0.9 ml min-1 kg-1) but was higher than that of 125I-iothalamate (5.4 +/- 0.6 ml min-1 kg-1). Extraction efficiencies of 99Tcm-cystine, 131I-OIH and 125I-iothalamate were 39 +/- 5, 64 +/- 4 and 27 +/- 3, respectively. The glomerular filtration components of 99Tcm-cystine and 131I-OIH were 26 and 16% of their respective clearances. In probenecid-treated animals the clearance of both agents was affected to a similar extent and fell to half of their respective control values, whereas tubular secretory components were found to be 19 and 31% of the controls. The kidney images obtained with 99Tcm-cystine were superior to those obtained with 99Tcm-GHA at different time points. Therefore, considering both renal function and imaging properties of 99Tcm-cystine it appears that this radiopharmaceutical offers some definite advantages over the currently available renal agents and commands further study.

Anoxic changes in cerebral cortex of albino rats following experimental carotid occlusion

Neuronal and glial changes following experimental cerebral ischaemia showed neuronal shrinkage and astrocytic proliferation after temporary bilateral clamping of carotid arteries, and extensive neuronal damage with areas of haemorrhage following bilateral carotid ligations in rats.

Alteration of spermatozoal structure and trace metal profile of testis and epididymis of rat under chronic low-level X-ray irradiation

This study investigates the short-term as well as long-term effects of low-level X-ray irradiation on the Spermatozoal structure and trace metal (Zn, Fe, Cu, and Cd) contents in the testis and epididymis of whole-body irradiated albino rats. Male rats were exposed to 0.675, 1.350, 2.700, and 4.050 cGy of X-ray intermittently in 45, 90, 180, and 270 equal fractions (each fraction of 0.015 cGy s-1), respectively. SEM study had revealed numerous fusiform swelling in sperm tail in most of the x-irradiated groups. Moreover, in 2.700 and 4.050 cGy dose groups, the tail sheath of several sperm were eroded out. In the TEM study, damage in microtubules of sperm tail in 4.050 cGy irradiated group was noted. The AAS study showed a transient increase in Zn content in 0.675 and 1.350 cGy dose groups, but its concentration was decreased in 2.700 and 4.050 cGy dose groups. Fe concentration was increased in all the cases in comparison to that of control group. Nevertheless, Cu and Cd contents were increased mostly in 2.700 and 4.050 cGy doses. Thus present findings probably throw some light regarding mammalian response threshold at low-level X-ray irradiation. Moreover, it raises questions regarding the validity of "safe dose ionizing radiation."

Collagen, zinc & iron contents of rat skin irradiated with chronic low-dose X-ray

The effects of very low-dose X-ray on collagen and Zn and Fe contents of rat skin were studied. CFS male rats were exposed to chronic, intermittent low dose X-radiation at the dose rate of 0.015 cGy/sec/day (7 days irradiation alternating with 7 days rest) for periods of three months and six months. Transmission electron microscopy showed hyalinization collagen on days 180 and 360 in the six months group. Atomic absorption spectrometry revealed significantly decreased zinc levels (P < 0.001) only on day 360 in six months group whereas iron increased significantly (P < 0.001) in all treated groups. This radiation induced redistribution of zinc and iron and subsequent changes in dermal collagen possibly confirm the hazardous effect of long term exposure to X-rays. Our findings also provide some information on the mammalian response threshold at low dose X-irradiation.