Biomedical subjects

R D Helme

Publications and source records attributed to R D Helme.

89 records · Page 5Linked to original sources

PubMed1985

The prognostic significance of intraventricular haemorrhage.

It is a generally held view that intraventricular haemorrhage carries a poor prognosis in cases of intracranial haemorrhage. We tested this view by retrospective analysis of the records of 258 patients who had intracranial blood on CT scans seen over a seven-year period. The mortality and morbidity for intraventricular and non-intraventricular haemorrhage were compared for the three major causes of intracranial bleeding, viz. aneurysm, trauma, and spontaneous intracerebral haemorrhage. No significant difference was found between the two groups for each aetiological category. It was concluded that the CT scan finding of intraventricular blood has no prognostic significance.

Brain Injuries↗

PubMed1983

Immunohistochemical localization of substance P in postmortem rat and human spinal cord.

The stability of substance P-like immunoreactivity was examined in postmortem rat and human spinal cord using radioimmunoassay and indirect fluorescence immunohistochemistry. The distribution of fluorescence in rat and human spinal cord was unchanged at intervals up to 48 hours (h) and 87 h, respectively. Fine linear fluorescent fibers were seen only in rat spinal cord processed at time intervals up to two h postmortem; they were never observed in human spinal cord, which was routinely obtained more than 6 h postmortem. The content of substance P-like material in human spinal cord nd its immunohistochemical appearance was not affected by age, the nature of the terminal illness, or autopsy delay. However, no correlation was found between intensity of fluorescent staining and content as measured by radioimmunoassay. It may be possible to use postmortem analysis of substance P in diseases of the central nervous system, but radioimmunoassay and immunohistochemistry should be used concurrently.

Animals↗

PubMed1983

Enkephalins and Endorphins. Clinical, pharmacological and therapeutic implications.

During the past 8 years there has been substantial progress in our understanding of the structure, distribution and action of endogenous opioid peptides. Currently, there appear to be 2 groups of peptides; those derived from beta-lipotropin and an enkephalin-related group. Some of these peptides have been shown to be distributed widely in the central nervous system and in endocrine tissues. The activity of the peptides probably occurs at several receptors but only 1 relatively specific (mu-receptor) antagonist, naloxone, is well studies. Although there have been many clinical studies of the action of opioids in man, no novel therapeutic applications have yet been established in clinical practice. Of the many areas of involvement attributed to opioids, those of analgesia, reproductive endocrinology, opiate dependence, and certain as yet undefined subtypes of major psychoses seem reasonably promising. Speculation surround opioid involvement in other disorders such as spinal trauma, septic shock, alcohol dependence, "functional' gastrointestinal disease, diabetes and asthma is of considerable interest but is supported by less clinical evidence. It seems that as research in opioids advances, the putative physiological opioid "spheres of influence' widen. At the same time, opioid mechanisms of action are being revealed to be more subtle and complex than previously thought. As a consequence, the expectations of rapid therapeutic application of opioid peptides and their antagonists are being modified and refined and realistic research strategies applied. In view of the work reviewed in this paper it seems reasonable to expect that such work will pay dividends in the not too distant future.

Acupuncture Therapy↗

PubMed1983

Substance P in the trigeminal system at postmortem: evidence for a role in pain pathways in man.

It is suspected that substance P has a role in primary afferent neurotransmission specifically concerned with nociception. This hypothesis has been developed from studies using experimental animals. In the present study indirect immunofluorescence has been used to examine the distribution of substance P-containing neurones in the human trigeminal system. The 5 specimens examined were obtained at autopsy. The antibody has been characterised by radio-immunoassay. In addition, neutralisation tests were performed. Approximately 15% of the neuronal perikarya observed in the trigeminal ganglia contained substance P-like material. The central nerve terminal distribution of these neurones was observed in the peripheral layers of nucleus caudalis and the caudal regions of the nucleus interpolaris. Peripheral distribution of fibres, presumably axon terminals, was observed in the dermis of the scalp subjacent to the epidermis. Rarely, fibres penetrated the lower layers of the epidermis. Nerve fibres were seen in the media and adventitia at the origin of the major cerebral vessels, the middle meningeal, muscular and scalp arteries. Nerve fibres were not observed elsewhere in muscle, in the leptomeninges or dura mater, except in and immediately adjacent to the venous sinuses. The distribution of substance P-containing neurones correlates closely with clinical studies which document the blood vessels and skin as the major pain sensitive structures of the scalp and cranium. This is evidence in man that substance P is involved in nociceptive pathways.

Blood Vessels↗

PubMed1981

Immunological studies of brain-specific antigens.

Central nervous system antigens have been investigated, using immunofluorescence, to demonstrate the presence of antisera raised against regional homogenates of neonatal and adult rat brain. Heterologous antisera raised in rabbits against regions of rat brain contained several antibodies demonstrated by immunofluorescence. Brain-specific activity directed against neuronal and glial elements was difficult to characterise. Regional and age-dependent specificity of the antisera was not demonstrated. Homologous antisera could not be raised against neonatal rat brain regions, but low titre antibodies to neurones were detected in rats over 21 days old. These animals did not develop experimental allergic encephalomyelitis (EAE). In other rats which developed EAE following a different immunisation schedule similar antibodies were seen. It is concluded that heterologous antisera raised against unpurified antigens have too wide a spectrum of antibody specificities for use as anatomic markers. Homologous antisera are difficult to obtain in sufficiently high titre. There is production of antibodies towards neurones in one form of EAE.

Animals↗

PubMed1981

Substance P in the central nervous system.

A radioimmunoassay has been developed for measuring substance P-like immunoreactivity. Assay sensitivity was 0.7fmoles of substance P. Using the radioimmunoassay substance P-like immunoreactivity was detected in postmortem tissue samples from the central nervous system of rats and humans. Immunofluorescence studies confirmed the localisation of substance P in the dorsal horn of the spinal cord.

Animals↗

PubMed1974