A method for the localization of adrenergic nerves during early development

Summary Problems associated with the low intensity and fast fading of the formaldehydeinduced fluorescence of adrenergic nerves in young foetal human and rat gut have been overcome by loading the nerves with a primary catecholamine. This has been achieved by incubating the tissue, before freeze-drying, in Krebs solution containing added noradrenaline or -methyl-noradrenaline. With this method fluorescent nerves have been revealed at a stage before any were demonstrable by normal procedures.This work was supported by the Australian Research Grants Committee and the National Heart Foundation of Australia. One of us (J. B. R.) was in receipt of a Commonwealth of Australia Postgraduate Award. We thank Prof. C. Wood for the human foetal material obtained, by hysterotomy, at legal terminations of pregnancy.     

A new technique for the long-term study of the physiology of plant fruit tissue slices

Parkin, K. L. 1987. A new technique for the long-term study of the physiology of plant fruit tissue slices.
A modified tissue culture medium, devoid of plant growth hormones, was evaluated as a means to allow long-term study of the physiology of plant fruit tissue slices. Tomato ( Lycopersicon esculentum Mill, cvs New Yorker and Caruso) tissue slices, prepared from mature green fruits, were mounted in this medium and examined for their capability to undergo ripening. Over a 30 day period the changes in color, firmness and respiratory activity for the slices appeared to be temporally associated as is the case for the intact fruit. A less distinct respiratory climacteric was noted for the incubated discs compared to the intact fruit. This new technique might be applicable to long-term study of other plant tissues.     

A new approach to teaching human cardiovascular physiology using Doppler ultrasound

Doppler ultrasound techniques are used extensively in clinical investigations to detect blood flow and measure its velocity. The application of these techniques in the teaching of cardiovascular physiology is of enormous potential educational value. A number of cardiovascular parameters that are difficult or even impossible to illustrate by conventional non-invasive methods can be demonstrated effectively, safely, and easily using Doppler ultrasound.

The principle of the technique is explained followed by examples of its potential use.     

A new protocol for studying the early events during liver regeneration

Hepatic amino acid transport and ornithine decarboxylase (ODC) activity were measured as early events during liver regeneration in rats adapted to a meal-feeding protocol in which food was presented during the first 2 hr of a daily 12-hr dark period. Surgeries were performed during the early hours of the light period, and food was withheld on the day following surgery to control the effect of feeding on the parameters measured. Initial experiments indicated that rats maintained on this schedule were capable of surviving partial hepatectomy. The survival rate was greater and the fat pads larger among 56-day-old than among 42-day-old rats; this indicated that animals with greater metabolic reserves were better suited for these experiments. The hepatic α-aminoisobutyric acid (α-AIB) distribution ratio and ODC activity increased above control values by 2 hr following partial hepatectomy. The α-AIB distribution ratio peaked at 10 hr after surgery and remained above control values for an additional 16 hr. In contrast, ODC activity peaked by 4 hr after surgery, followed by two smaller peaks at 10 and 20 hr. In sham-hepatectomized rats both the α-AIB distribution ratio and the ODC activity increased above control values by 3 hr after surgery, but fell to control values by 15 hr. These findings show that increases in amino acid transport and ODC activity following partial hepatectomy occur independently of feeding. The identical time course for the initiation of both of these events suggests that they result from a common effector.     

A new method for the early diagnosis of brain edema/brain swelling. An experimental study in rabbits

The aim of the present work is to develop a non-destructive, non-invasive technique for the early diagnosis of an oncoming brain edema based on the variation of vibration characteristics of the head system (i.e. eigenfrequency spectrum and modal damping). Besides the theoretical model that supports the basic principle, the proposed technique has been verified experimentally in animal tests. The advantage of such an approach is that the relative information is available well in advance an increase of intracranial pressure is detected. The uncontrolled intracranial hypertension is associated with increased mortality or vegetative state in head trauma. Traumatic lesions located on temporal lobe render particularly impeding the transtendorial herniation. From the medical point of view, intracranial pressure (ICP) monitoring represents an effective way for early consideration of neurological decompensation in various neurosurgical conditions particularly in the head-injured setting. However, the use of ICP monitoring is not an effective way of brain edema detection, since ICP increase very often causes irreversible problems to the patient's brain. Therefore, the determination of an earlier, less invasive and more sensitive indicator of the oncoming intracranial hypertension and of the impeding neurological deterioration is of profound importance.

The present work aims at experimental verification of both eigenfrequency shifting and modal damping increase of the spectral response of the head system of rabbits, wherever a mass increase in the content of cranial shell appears. The conducted analysis concludes that the eigenfrequency spectrum and its modal damping characteristics are sufficiently sensitive parameters in order to characterize mass increase in the cranial shell.

Therefore the combination of both the above parameters could be used with confidence for the early diagnosis of brain edema.     

A new dried nutrient medium for the isolation of Corynebacterium diphtheriae (its development and experimental study)

A new dried diagnostic medium for the isolation of C. diphtheriae has been developed on the basis of aminopeptide. This new aminopeptide-based medium compares favorably with Buchin's medium in its growth and inhibitory properties.     

A quantitative study of epithelial alterations during the early stages of experimental colonic tumorigenesis in mice

The weekly administration of 1,2-dimethyl-hydrazine (DMH) by subcutaneous injection for a period of 16-20 weeks is a well known procedure for producing colonic tumors in mice and rats. Quantitative histomorphological, histochemical and kinetic studies, as well as investigation of the significance of epithelial cell density were carried out in mice between the 7th and the 91st day after the first DMH injection. These studies showed that between the 28th and the 35th day, several simultaneous alterations in the colonic epithelium involving modification of glandular form, decreased mucus secretion, an increase in epithelial cell density and an increase in the number of S phase cells (BrdU labeling index: LI). Around the 35th day, the glands tended to expand and from the 35th to the 63rd day, they were stretched and displayed compartments of dedifferentiated and non-mucinous crypts (DNMC). In these crypts the cell density became very high, reaching twice the control value on the 91st day. This feature was accompanied by alteration in cell morphology and by an increase in the available basement membrane area. A decrease in mucus secretion was apparent from the 14th day and by the 63rd day, mucus secretion was only about 60% of the control value in all crypts. The LI was increased until the 35th day following which a paradoxical and progressive decrease occurred in all glandular compartments.     

A new experimental system for study on adaptive mutations

A super-repressed mutant of purR (purRs), which encodes a repressor protein controlling expression of purine biosynthetic genes in Salmonella typhimurium, grew very slowly on NCE medium with 10 μg/mL Ade and lactose as sole carbon source (cannot form colonies). However, a phenomenon of late-arising mutations was observed when purRs mutants were spread on NCE+lactose plates and subjected to a prolonged non-lethal selection. The reconstruction experiments of revertants showed that the late-arising "lac+" mutants are not slow growing mutants. Statistical analysis indicated that the distribution of late-arising mutants is Poisson distribution, showing that reversion occurred after plating. The result of co-transductional analysis preliminarily showed that late-arising mutation occurred at selected gene purR or 16 bp PUR box, cis element of structural gene purD. The above results suggest that the phenomenon of late-arising mutation observed by our system is a result of adaptive mutations which are different     

A new experimental system for study on adaptive mutations

A super-repressed mutant of purR (purR^S), which encodes a repressor protein controlling expression of purine biosynthetic genes inSalmonella typhimurium, grew very slowly on NCE medium with 10 μg/mL Ade and lactose as sole carbon source (cannot form colonies). However, a phenomenon of late-arising mutations was observed when purR^S mutants were spread on NCE+lactose plates and subjected to a prolonged non-lethal selection. The reconstruction experiments of revertants showed that the late-arising “lac⁺” mutants are not slow growing mutants. Statistical analysis indicated that the distribution of late-arising mutants is Poisson distribution, showing that reversion occurred after plating. The result of co-transductional analysis preliminarily showed that late-arising mutation occurred at selected genepurR or 16 bp PUR box,cis element of structural genepurD. The above results suggest that the phenomenon of late-arising mutation observed by our system is a result of adaptive mutations which are different from random mutations. This is the first time to extend target genes at which adaptive mutations could occur from structural genes involved in carbon metabolism and amino acid biosynthesis totrans regulatory gene coding repressor protein. Our results have provided not only a new proof for generality of adaptive mutations but also a new system for study on adaptive mutations.     

Nanoparticle-biomolecular corona: A new approach for the early detection of non-small-cell lung cancer

Lung cancer (LC) is the most common type of cancer and the second cause of death worldwide in men and women after cardiovascular diseases. Non-small-cell lung cancer (NSCLC) is the most frequent type of LC occurring in 85% of cases. Developing new methods for early detection of NSCLC could substantially increase the chances of survival and, therefore, is an urgent task for current research. Nowadays, explosion in nanotechnology offers unprecedented opportunities for therapeutics and diagnosis applications. In this context, exploiting the bio-nano-interactions between nanoparticles (NPs) and biological fluids is an emerging field of research. Upon contact with biofluids, NPs are covered by a biomolecular coating referred to as “biomolecular corona” (BC). In this study, we exploited BC for discriminating between NSCLC patients and healthy volunteers. Blood samples from 10 NSCLC patients and 5 subjects without malignancy were allowed to interact with negatively charged lipid NPs, leading to the formation of a BC at the NP surface. After isolation, BCs were characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). We found that the BCs of NSCLC patients was significantly different from that of healthy individuals. Statistical analysis of SDS-PAGE results allowed discriminating between NSCLC cancer patients and healthy subjects with 80% specificity, 80% sensitivity and a total discriminate correctness rate of 80%. While the results of the present investigation cannot be conclusive due to the small size of the data set, we have shown that exploitation of the BC is a promising approach for the early diagnosis of NSCLC.     

A combined bioinformatics and chemoinformatics approach for the development of new antiparasitic drugs

A modern concept for the development of novel antiparasitic drugs is the combination of bioinformatics and chemoinformatics approaches. This covers, for example, the identification of target proteins serving as molecular points of attack for parasiticides--the idea is that, owing to some essential role, inhibition of a target protein should eradicate the parasite. To prevent toxicity problems for vertebrate host organisms, it is advantageous that these proteins show significant differences from their vertebrate counterparts. In the present work, we identified potential target proteins in parasitic nematodes (Ascaris suum, Brugia malayi, and Haemonchus contortus) and arthropods (Boophilus microplus and Rhipicephalus appendiculatus) using bioinformatic sequence comparison methods on expressed sequence tags. Interesting target proteins (e.g., S-adenosyl-l-methionine synthetase) were characterized in detail by subjecting them to in-depth bioinformatic analysis. S-Adenosyl-l-methionine synthetase was also used to elucidate chemoinformatics approaches like homology modeling and docking, which represent appropriate methods for generating valuable data for the development of new drug candidates.     

A new parametric approach for modeling hip forces during gait

An analytical parametric model was developed to estimate the natural biological variations in muscle forces and their effect on the hip forces subject only to physiological constraints and not predefined optimization criterion. Force predictions are based on the joint kinematics and kinetics of each subject, a previously published muscle model, and physiological constraints on the muscle force distributions. The model was used to determine the hip contact forces throughout the stance phase of gait of a subject with a total hip replacement (THR). The parametrically modeled peak hip force without antagonistic muscle activity varied from 2.7 to 3.2 Body Weights (mean 2.9 Body Weights), which agreed well with published in vivo measurements from instrumented THRs in other subjects. For every 10% increase in antagonistic activity, the mean peak hip force increased by 0.2 Body Weights. The parametric model allows one to examine the effect of specific muscle weaknesses or increased antagonistic muscle activity on the hip forces. The model also provides a tool for studying the effect of gait adaptations on hip forces, as predictions are based on each individual's gait data. Differences in peak forces between subjects can then be evaluated relative to the uncertainty in not knowing the precise muscle force distributions.