Simulation of laser tomoscopy in a heterogeneous biological medium

A Monte Carlo model has been developed to study the propagation of an ultrashort light pulse through a heterogeneous thick biological specimen. A circular blood vessel is moved within a tissular slab to simulate biological specimen scanning using a picosecond laser source and a collimated ultrafast multichannel opticl shutter. Features of the transmitted light are computed for each position of the blood vessel. The computer program gives an account of the transmitted photons, the flight time which does not exceed straightforward crossing time plus time gate of known duration. A small blood vessel (radius R=2 mm) placed in a 40 mm thick slab is easily located when a time gate of 10 ps duration is employed. Such a time gate also allows the detection of a middle-sized vessel (R=4 mm) embedded in a thicker sample (80 mm). The contrast computed for the transmittance profile is greatly improved when a time gate is used. In addition, shifting of the blood vessel towards the unilluminated side of the sample decreases the contrast. We demonstrate that the time selection process may provide a substantial improvement to the laser tomoscopy technique when used for imaging biological media.     

Bacterial lipopolysaccharide mediates the loss of CD4 from the surface of purified peripheral blood monocytes.

In this study we have looked at the effect of lipopolysaccharide (LPS) on the surface antigen expression of cultured monocytes. Monocytes were purified from peripheral blood mononuclear cells (PBMC) and cultured in the presence or absence of LPS. The cultured cells were then stained with anti-MO3, anti-IL-2R and anti-CD4 MoAbs. We have shown that freshly isolated monocytes are IL-2R- and MO3-negative and express CD4 in low density. After overnight culture, without LPS, the expression of these surface markers remained relatively unchanged. However, in the presence of LPS (1 microgram/ml) CD4 expression was reduced to undetectable levels while the expression of IL-2R and MO3 was induced to maximal density. This effect of LPS on monocyte surface antigen expression was demonstrated with LPS preparations from Escherichia coli, Salmonella typhi and Vibrio cholerae. Surface antigen expression after 7 days culture in medium supplemented with non-heat-inactivated serum was essentially as seen after overnight culture, with the exception that LPS-induced IL-2R expression was transient. The ability to prepare monocytes that maintained surface CD4 expression after overnight culture was donor dependent.     

Envenomation by the inland taipan, Oxyuranus microlepidotus

A case of envenomation by a three-week-old inland taipan (Oxyuranus microlepidotus)-the second recorded case of a bite by possibly the most venomous snake in the world - is reported. Evidence which supports the use of the term "inland taipan", and confirms the effectiveness of taipan antivenom in the treatment of bites by this snake, is presented.     

Achieving hospital operating objectives in the light of patient preferences

Patient satisfaction is becoming increasingly important for the successful operation of private and public hospitals. The quality of the service provided can be improved if internal and external customers' opinions are taken into account during the definition of hospital operating objectives. This research presents a new methodology, called the simulation service quality system (SSQS), developed to improve operating performance measures in the light of customer preferences. The motivation for the development of the SSQS methodology arose from the need to achieve timeliness standards at United States Veterans' Hospitals. The Harry S. Truman Memorial Veterans' Hospital in Columbia Missouri served as the validation and initial application site for the SSQS methodology. Details one such project: the objective of reducing customer waiting times to 30 minutes or less at an outpatient treatment clinic. Through the identification of relationships and interactions, discrete-event simulation techniques are applied to model and experiment with the system to ultimately arrive at recommended changes in hospital operating policies which achieve the objective.     

Patients with lower motor spinal cord lesion: a decrease of vasoactive intestinal polypeptide, calcitonin gene-related peptide and substance P, but not neuropeptide Y and somatostatin-immunoreactive nerves in the detrusor muscle of the bladder.

Specimens of the detrusor muscle of the bladder from four patients with lower motor neurone lesion and three patients with carcinoma of the bladder used as "controls", were studied immunohistochemically for vasoactive intestinal polypeptide, neuropeptide Y, calcitonin-gene related peptide, substance P and somatostatin. The greatest density of nerves in the bladder from "control" patients contained neuropeptide Y, followed in a decreasing order by vasoactive intestinal polypeptide, calcitonin gene-related peptide, substance P and somatostatin. Neuropeptide Y- and vasoactive intestinal polypeptide-immunoreactive nerves were found throughout the smooth muscle and the base of the mucosa, while calcitonin gene-related peptide-, substance P- and somatostatin-immunoreactive nerves were found predominantly in nerve bundles with a few single fibres at the base of the mucosa. Vasoactive intestinal polypeptide-, neuropeptide Y- and calcitonin gene-related peptide-immunoreactive nerves were also located around blood vessels. In patients with lower motor neurone lesion, there was a decrease in the density of vasoactive intestinal polypeptide-, calcitonin gene-related peptide- and substance P-immunoreactive nerves, but there was little change in neuropeptide Y- or somatostatin-immunoreactive nerves. Urinary retention, bladder areflexia and deficient sensation may be directly linked to neuropeptide neuropathy in patients with lower motor neurone lesion.     

Out-of-hours calls in a Leicestershire practice.

In one year, 920 "out-of-hours" calls were received by a partnership of three general practitioners working from a health centre in semi-rural Leicestershire. The partners on duty saw 588 patients. Out of 898 patients on whom information was available only 75 (8-5%) were referred to hospital, mainly as casualties. The results are compared with a study of deputising services, and it is concluded that a partnership covering its own out-of-hours calls can provide a more personal service and appears to make fewer demands on NHS resources.     

Mitral stenosis obscuring the diagnosis of plexogenic pulmonary arteriopathy and familial pulmonary hypertension

A patient who died after surgery for critical mitral stenosis was found to have underlying unrecognised plexogenic pulmonary arteriopathy and familial pulmonary hypertension. The importance of recognising familial pulmonary hypertension is discussed, together with the contribution of genetic and other risk factors to plexogenic pulmonary arteriopathy.