Computerized determination of blood flow in pedicle flaps by the clearance of epicutaneously applied 133Xenon

Determination of the rate of clearance of ¹³³Xe has been used to calculate skin blood flow in pedicle flaps. The epicutaneous route of application was found particularly suitable in reducing artifact. Computer analysis of data simplified and increased the accuracy of calculation of flow and also confirmed the validity of the biexponential model for washout of ¹³³Xe from skin and subcutaneous tissue. Computer analysis of curve fit aided in assessing the reliability of individual clearance studies. Preliminary findings in patients undergoing flap construction have indicated a good correlation between flow measured in this fashion and the clinical-status of flaps.This method holds potential as a tool for investigating the mechanism of delay as well as for evaluating the effects of plasma volume expanders, anticoagulants, antiplatelet agents, and other therapeutic modalities employed when skin blood flow is compromised. Additionally, this computerized method of determining skin blood flow from the clearance of epicutaneously applied ¹³³Xe may be useful in designing flaps, as well as in timing the delay and division of flaps. The method could be applied to determination of level of amputation, assessment of revascularization procedures, and measurement of the effectiveness of pharmacological or surgical sympathectomy.     

Medroxyprogesterone acetate and tamoxifen do not decrease aggressive behavior in CF-1 male mice

Intact CF-1 male mice were given daily injections of either medroxyprogesterone acetate (MPA, an antiandrogen), tamoxifen (TAM, an antiestrogen), or the two drugs in combination and tested for aggressive behavior toward bulbectomized stimulus males. None of the treatments decreased fighting behavior over a 20-day test period and the presence of TAM led to increased aggression even in the presence of MPA. Testis weight was reduced by MPA while both compounds decreased seminal vesicle weight. The mechanisms involved in the observed effects are considered as well as the implications of the results for the clinical use of these compounds as modulators of testosterone-facilitated behaviors.     

The effect of central stimulant drugs on acetylcholine release from rat cerebral cortex

1. The effects of central stimulant drugs injected intraperitoneally were examined on the release of acetylcholine (ACh) from the cerebral cortex of the anaesthetized rat. The effects of the drugs in increasing ACh release were approximately parallel to the increases produced in the electrical activity of the brain.2. Leptazol in a dose of 150 mg/kg increased the release of ACh by 2.9 times the resting release and in a dose of 300 mg/kg by 7.5 times; on the e.e.g. the injection produced a large increase in the electrical activity.3. Picrotoxin in a dose of 12 mg/kg increased the release of ACh by 7.5 times and on the e.e.g. caused a large increase in activity.4. Strychnine in doses of 8 mg/kg and 12 mg/kg increased the release of ACh by 2.0 and 2.4 times and produced a small increase in the activity of the e.e.g.5. Dexamphetamine in a dose of 100 mg/kg increased the release of ACh by 1.9 times and had no appreciable effect on the e.e.g.6. Nikethamide in a dose of 2 g/kg increased the release of ACh by 2.3 times and produced no appreciable change in the e.e.g.7. Caffeine in a dose of 100 mg/kg produced no significant effect on the release of ACh.     

Weak prepulses inhibit but do not elicit startle in rats and humans.

BACKGROUND: Inhibition of startle by weak prestimuli is called prepulse inhibition (PPI). It has recently been reported that 10- to 20-dB prepulses trigger eye-blink motor activity and PPI in normal human subjects. Motor activity after prepulses correlated negatively with PPI in four of nine possible conditions. We now report the relationship between prepulse-elicited startle (PPES) and PPI using weak prepulses. METHODS: We assessed PPI and PPES using 1- to 5-dB prepulses in humans and in rats after treatment with vehicle or apomorphine. RESULTS: Prepulses inhibited startle in an intensity-dependent fashion but elicited no startle activity in humans or rats. Apomorphine eliminated PPI in rats and produced a well-documented increase in stimulus-independent motor activity but did not stimulate PPES. CONCLUSIONS: In humans and rats, PPES is not a necessary condition for either the elicitation or the disruption of PPI.     

Development of tolerance to the effects of vigabatrin (gamma-vinyl-GABA) on GABA release from rat cerebral cortex, spinal cord and retina.

1. The effects of acute and chronic vigabatrin (gamma-vinyl-GABA) (GVG) administration on gamma-aminobutyric acid (GABA) levels and release in rat cortical slices, spinal cord slices and retinas were studied. 2. GVG (250 mgkg-1 i.p.) administered to rats 18 h before death (acute administration) produced an almost 3 fold increase in GABA levels of the cortex and spinal cord and a 6 fold increase in retinal GABA. The levels of glutamate, aspartate, glycine and taurine were unaffected. 3. When GVG (250 mgkg-1 i.p.) was administered daily for 17 days (chronic administration) a similar (almost 3 fold) increase in cortical GABA occurred but the increases in spinal and retinal GABA were reduced by approximately 40%. 4. Acute administration of GVG strikingly increased the potassium-evoked release (KCl 50 mM) of GABA from all three tissues. This enhanced evoked release was reduced by about 50% in tissues taken from rats that had been chronically treated with GVG. 5. Acute administration of GVG reduced GABA-transaminase (GABA-T) activity by approximately 80% in cortex and cord and by 98% in the retina. Following the chronic administration of GVG, there was a trend for GABA-T activities to recover (significant only in cortex). Acute administration of GVG had no effect on glutamic acid decarboxylase (GAD) activity in cortex or spinal cord. However, chronic treatment resulted in significant decreases in GAD activity in both the cortex and cord (35% and 50% reduction respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

Spontaneously resolvingUreaplasma urealyticum meningitis

We report this case of a preterm infant with intraventricular haemorrhage who hadUreaplasma urealyticum isolated from the CSF together with a CSF pleocytosis both of which spontaneously cleared.     

Targeted therapies in colorectal cancer: Complications and management

The promise of targeted therapeutics is tumor selectivity. The gold standard for this approach is monoclonal antibodies with exquisite target specificity. In the case of colorectal cancer, this promise has been partially fulfilled. The epidermal growth factor and vascular endothelial growth factor pathways were identified as putative therapeutic targets and inhibitory antibodies were developed with clinical activity. However, although these reagents are not associated with toxicities characteristic of traditional cytotoxics, they are not devoid of side effects. In fact, these side effects can generally be explained on the basis of expected biologic effects of the reagents, highlighting the notion that targets with true tumor specificity remain elusive. In this review, we will profile the unique toxicities associated with monoclonal antibody inhibitors of the epidermal growth factor receptor and vascular endothelial growth factor, and offer suggestions for management.