Future directions

In this final paper, we summarise briefly the principal conclusions to emerge from the conference. We also review possible future directions in the light of the contributions of different authors and discussions at the conference. The paper argues that changes in the Swedish health services are both inevitable and desirable. The challenge is to maintain the strengths of the existing system while tackling widely acknowledged weaknesses. It is not yet clear what will emerge from the process of reform but the probable outcome is a period of innovation and experimentation leading to greater diversity in service provision. We argue that diversity is most likely to develop within the context of a continuing commitment to equity and comprehensiveness in the delivery of health care.     

Abnormalities of cerebral oxidative metabolism in animal models of Parkinson disease

Abnormalities of cerebral oxidative metabolism were investigated in "animal models" of Parkinson disease by in situ optical measurements of local cerebral blood volume and cytochrome oxidase redox shifts in rats two weeks after unilateral 6-hydroxydopamine lesions of the substantia nigra with or without interruption of ascending noradrenergic pathways. The data demonstrate oxidative metabolic dysfunction of ipsilateral cerebral hemispheres caused by lesions that involve both dopaminergic and noradrenergic systems but not when dopaminergic neurons only are affected. We speculate that the dementia of Parkinson disease may be more prevalent when degeneration of catecholaminergic systems is widespread and not restricted to the dopaminergic system.     

Cell-surface characteristics of hairy cell leukemia in seven patients.

Surface marker studies were performed on "hairy cells" from 7 patients with hairy cell leukemia (HCL). Using sensitive analytic techniques including specific antisera and Fluorescence Activated Cell Sorter (FACS-1), further definition of the abnormal cell was achieved. Four different antisera were used in infestigating the cell surface characteristics of these patients: anti-p23,30, an antiserum reactive with B cells and a subset of monocytes, anti-311, which reacts only with T cells, pepsin digested anti-F(ab')2 which reacts with B cells only and pepsin digested anti-lysozyme reactive with monocytes and myeloid cells, but not with B or T cells. In all cases strong reactivity was observed with anti-p23,30 and anti-F(ab')2, but no reactivity with anti-311. Five out of the seven cases were reactive with anti-lysozyme in a pattern similar to normal monocytes. Furthermore, when cells were separated according to binding to anti-p23,30, anti-F(ab')2 and anti-lysozyme and in two cases, according to cell size, the majority of reactivity and large cells were "hairy" when examined under microscopy. In contrast, the small and nonreactive (dull cells) appeared as normal mature lymphocytes. Thus, our data supports the view that HCL cells bear in most cases B cell and monocytic membrane markers.     

The effect of independent collimator misalignment on the dosimetry of abutted half-beam blocked fields for the treatment of head and neck cancer.

BACKGROUND AND PURPOSE: Independent collimation conveniently allows for the junctioning of abutting fields with non-diverging beam edges. When this technique is used at the junction of multiple fields, e.g. lateral and low anterior fields in three-field head and neck set-ups, there should be a dosimetric match with no overdose or underdose at the matchline. We set out to evaluate the actual dosimetry at the central match plane. MATERIALS AND METHODS: Independent jaws were used to mimic two half-beam blocked fields abutting at the central axis. X-Ray verification film was exposed in a water-equivalent phantom and the dose at the matchline was evaluated with laser densitometry. Collimators were then programmed to force a gap or overlap of the radiation fields to evaluate the effect of jaw misalignment within the tolerance of the manufacturer's specification. Diode measurements of the field edges were also performed. Four beam energies from four different linear accelerators were evaluated. RESULTS: Small systematic inhomogeneities were found along the matchline in all linear accelerators tested. The maximum dose on the central axis varied linearly with small programmed jaw misalignments. For a gap or overlap of 2 mm between the jaws, the matchline dose increased or decreased by 30-40%. The region of overdose or underdose around the matchline is 3-4 mm wide. The discrepancy between the width of jaw separation and the width of the region of altered dose is explained by a penumbra effect. CONCLUSION: We recommend that independent jaw alignment be evaluated routinely and provide a simple method to estimate dose inhomogeneity at the match plane. If there is a field gap or overlap resulting in a clinically significant change in dosimetry, jaw misalignment should be corrected. If it cannot be corrected, part of the benefit of asymmetric collimation is lost and other methods of field junctioning may have to be considered. We routinely use a small block over the spinal cord at the mono-isocenter set-up plane for three-field head and neck treatments to prevent an overdose.     

Is there an incremental rise in the risk of obstetric intervention with increasing maternal age?

Objective To determine whether increasing maternal age increases the risk of operative delivery and to investigate whether such a trend is due to fetal or maternal factors.
Design Analysis of prospectively collected data on a maternity unit database.
Setting A postgraduate teaching hospital.
Population 6410 nulliparous women with singleton cephalic pregnancies delivering at term (37–42) weeks of gestation) between 1 January 92 and 31 December 95.
Main outcome measures Mode of delivery, rates of prelabour caesarean section, induction of labour and epidural usage.
Results There was a positive, highly significant association between increasing maternal age and obstetric intervention. Prelabour (  P < 0.001  ) and emergency (   P < 0.001  ) caesarean section, instrumental vaginal delivery (spontaneous labour   P < 0.001  ; induced labour   P = 0.001  ), induction of labour (   P < 0.001  ) and epidural usage in spontaneous labour (  P = 0.005  ) all increased with increasing age. In the second stage of labour fetal distress and failure to advance, requiring instrumental delivery, were both more likely with increasing maternal age (in both   P < 0.001  ). Epidural usage in induced labour and the incidence of small for gestational age newborns did not increase with increasing maternal age (P = 0.68 and  P = 0.50  , respectively).
Conclusions This study demonstrates that increasing maternal age is associated with an incremental increase in obstetric intervention. Previous studies have demonstrated a significant effect in women older than 35 years of age, but these data show changes on a continuum from teenage years. This finding may reflect a progressive, age-related deterioration in myometrial function.     

Mechanisms of systemic hypertension during acute elevation of intraabdominal pressure

INTRODUCTION: In previous studies we described mechanisms by which acute elevation of the intraabdominal pressure (IAP) induces intracranial hypertension (ICHTN). Here we sought to define the role of ICHTN in mediating systemic hypertension (HTN) during CO(2) pneumoperitoneum (PNP). METHODS: Six large animals (swine) were hyperventilated to buffer hypercarbia. Intracranial pressure (ICP) was monitored with a Camino intraparenchymal ICP monitoring system. A Foley catheter was introduced intracranially via a separate burr hole. At phase 1, changes in ICP, central venous pressure (CVP), and mean arterial pressure (MAP) were recorded during periods of CO(2) PNP at IAP levels of 15, 20, 25, and 30 mm Hg. At phase 2, ICHTN was produced directly by inflating the intracranial balloon to the same ICP levels that had been measured in phase 1 for each degree of IAP. CVP and MAP were recorded. Repeated measures analysis of variance was applied. RESULTS: At phase 1, the mean DeltaCVP, DeltaICP, and DeltaMAP increased relative to the degree of IAP (P = 0.0001, 0.0004, and 0.024, respectively). At phase 2, the increments in DeltaMAP were significant (P = 0.024) and in the same direction and amplitude as at phase 1. CONCLUSIONS: In this study, increasing the IAP with CO(2) PNP with a consequent increase of ICP and direct manipulation of the ICP produced a comparable systemic HTN. We believe that this further supports our hypothesis: Elevated IAP produces an immediate increase in the CVP, which impairs venous drainage from the central nervous system (CNS), increases the ICP, and initiates a CNS-mediated response and systemic HTN.