Trypsin induces epidermal proliferation and inflammation in murine skin

Human keratinocytes are known to express the protease-activated receptors, PAR-1 and PAR-2. Activation of PAR-1 results in increased proliferation, whereas PAR-2 activation results in decreased keratinocyte proliferation. Trypsin activates PAR-1 and in higher concentrations, PAR-2. The aim of this study was to evaluate the overall effect of trypsin on keratinocyte proliferation in a mouse in vivo and in vitro model. Daily topical application of 0.3-300 pmol trypsin/cm2 on hairless mouse skin induced dose-dependent epidermal hyperproliferation as determined by an increase in 5-bromo-2'-deoxyuridine incorporation of up to eight-fold in basal keratinocytes and an up to three-fold increase in keratinocyte layers. This was accompanied by an increased transepidermal water loss. These effects of trypsin were abolished by the addition of the trypsin inhibitor n-p-tosyl-l-lysine-chloromethyl ketone. Histological analysis revealed acanthosis, hypergranulosis, and spongiosis in the epidermis as well as vasodilatation and an inflammatory infiltrate in the upper dermis. In the murine keratinocyte cell line PAM-212 activation of PAR-1 with specific activating peptides resulted in a calcium influx and an increase of proliferation, whereas activation of PAR-2 caused a diminished proliferation. Incubation with trypsin, PAR-1-, and PAR-2-activating peptides induced cytokine-induced neutrophil chemoattractant (KC) mRNA expression as a marker for inflammation in PAM-212 in a dose-dependent manner. In conclusion, our results suggest that trypsin induces in vivo epidermal proliferation and inflammation. Proliferation seems not to be signaled by PAR activation, but PAR-2-induced KC chemokine expression may contribute in part to trypsin-induced inflammation.     

Low-field magnetic stimulation in bipolar depression using an MRI-based stimulator

OBJECTIVE: Anecdotal reports have suggested mood improvement in patients with bipolar disorder immediately after they underwent an echo-planar magnetic resonance spectroscopic imaging (EP-MRSI) procedure that can be performed within clinical MR system limits. This study evaluated possible mood improvement associated with this procedure. METHOD: The mood states of subjects in an ongoing EP-MRSI study of bipolar disorder were assessed by using the Brief Affect Scale, a structured mood rating scale, immediately before and after an EP-MRSI session. Sham EP-MRSI was administered to a comparison group of subjects with bipolar disorder, and actual EP-MRSI was administered to a comparison group of healthy subjects. The characteristics of the electric fields generated by the EP-MRSI scan were analyzed. RESULTS: Mood improvement was reported by 23 of 30 bipolar disorder subjects who received the actual EP-MRSI examination, by three of 10 bipolar disorder subjects who received sham EP-MRSI, and by four of 14 healthy comparison subjects who received actual EP-MRSI. Significant differences in mood improvement were found between the bipolar disorder subjects who received actual EP-MRSI and those who received sham EP-MRSI, and, among subjects who received actual EP-MRSI, between the healthy subjects and the bipolar disorder subjects and to a lesser extent between the unmedicated bipolar disorder subjects and the bipolar disorder subjects who were taking medication. The electric fields generated by the EP-MRSI scan were smaller (0.7 V/m) than fields used in repetitive transcranial magnetic stimulation (rTMS) treatment of depression (1-500 V/m) and also extended uniformly throughout the head, unlike the highly nonuniform fields used in rTMS. The EP-MRSI waveform, a 1-kHz train of monophasic trapezoidal gradient pulses, differed from that used in rTMS. CONCLUSIONS: These preliminary data suggest that the EP-MRSI scan induces electric fields that are associated with reported mood improvement in subjects with bipolar disorder. The findings are similar to those for rTMS depression treatments, although the waveform used in EP-MRSI differs from that used in rTMS. Further investigation of the mechanism of EP-MRSI is warranted.     

Tyrosine phosphatase inhibition induces loss of blood-brain barrier integrity by matrix metalloproteinase-dependent and -independent pathways

Tight junctions between endothelial cells of brain capillaries form the structural basis of the blood-brain barrier (BBB), which controls the exchange of molecules between blood and CNS. Regulation of cellular barrier permeability is a vital and complex process involving intracellular signalling and rearrangement of tight junction proteins. We have analysed the impact of tyrosine phosphatase inhibition on tight junction proteins and endothelial barrier integrity in a primary cell culture model based on porcine brain capillary endothelial cells (PBCEC) that closely mimics the BBB in vitro. The tyrosine phosphatase inhibitor phenylarsine oxide (PAO) induced increased matrix metalloproteinase (MMP) activity, which was paralleled by severe disruption of cell-cell contacts and proteolysis of the tight junction protein occludin. ZO-1 and claudin-5 were not affected. Under these conditions, the transendothelial electrical resistance (TEER) was markedly reduced. PAO-induced occludin proteolysis could be prevented by different MMP inhibitors. Pervanadate (PV) reduced the TEER similar to PAO, but did not increase MMP activity. Cell-cell contacts of PV-treated cells appeared unaffected, and occludin proteolysis did not occur. Our results suggest that tyrosine phosphatase inhibition can influence barrier properties independent of, but also correlated to MMPs. Evidence is given for a role of MMPs in endothelial tight junction regulation at the BBB in particular and probably at tight junctions (TJs) in general.     

Sciatic nerve regeneration in mice and rats: recovery of sensory innervation is followed by a slowly retreating neuropathic pain-like syndrome

Peripheral nerve regeneration has been studied extensively in the sciatic nerve crush model, at the level of both function and gene expression. The crush injury allows full recovery of sensory and motor function in about 3 weeks as assessed by the foot reflex withdrawal test and De Medinacelli walking patterns. We used the recently developed CatWalk paradigm to study walking patterns in more detail in mice and rats. We found that, following the recovery of sensory function, the animals developed a state of mechanical allodynia, which retreated slowly over time. The motor function, although fully recovered with the conventional methods, was revealed to be still impaired because the animals did not put weight on their previously injured paw. The development of neuropathic pain following successful sensory recovery has not been described before in crush-lesioned animals and may provide an important new parameter to assess full sensory recovery.     

Strict bed rest following lumbar puncture in children and adolescents is of no benefit

The effect of 24-hour bed rest or free mobility on the frequency of complaints following diagnostic lumbar puncture was studied in a randomized trial of 111 patients aged 2 to 17 years. Patients of the bed-rest group encountered significantly more head- or backaches (positional headache 15 vs 2%; all headaches 39 vs 21%; backaches 42 vs 23%). There were no differences in the frequencies of nausea or neck stiffness. Prophylactic bed rest following lumbar puncture in children and adolescents is of no benefit and may actually be disadvantageous.     

Effects of alcohol and drug use on inpatient and residential treatment among youth with severe emotional disturbance in Medicaid-funded behavioral health care plans

This study examined the use of alcohol and recreational drugs among 875 youth with severe emotional disturbance (SED) enrolled in Medicaid-funded behavioral health care plans, and whether co-occurring SED and substance use affected the subsequent likelihood of receiving inpatient and/or residential treatment. Youth at five sites nationwide were interviewed about their use of drugs and alcohol, while interviews with their caregivers elicited information about youths' service utilization, degree of functional impairment, and a series of demographic and environmental variables. Results indicated that half of the youth (52%) reported lifetime use of alcohol, street drugs, or over-the-counter medications for recreational purposes, while 18% reported use in the past 30 days. Among those reporting recent use, 32% reported using drugs only, 34% alcohol only, and 33% reported use of both drugs and alcohol. In multivariate logistic regression analyses, the effect of recent use was stronger than that of lifetime use; however, the largest effect occurred for those reporting recent use of both drugs and alcohol, versus either alone, or none. Differences remained significant when controlling for managed care versus fee for service enrollment as well as child, family, and environmental characteristics including study site. These results mirror those of prior studies that found an association between substance use and greater likelihood of inpatient services, even in managed care settings.     

Effect of maltose-containing sports drinks on exercise performance

This study examined the effect of maltose-containing sports drinks on exercise performance. Ten subjects completed 4 trials. Each trial consisted of a glycogen depletion protocol, followed by a 15-min refueling, after which subjects performed an 1-h performance test while consuming one of the experimental drinks (HGlu, glucose; HMal, maltose; MalMix, sucrose, maltose, and maltodextrin; Plac, placebo). Drinks provided 0.65 g/kg body weight carbohydrates during refueling and 0.2 g/kg every 15 min during the performance test. Although no significant differences were found in performance (HGlu: 67.2 +/- 2.0; HMal: 68.6 +/- 1.7; MalMix: 66.7 +/- 2.0; Plac: 69.4 +/- 3.0 min, P> 0.05), subjects completed the MalMix trial 3.9%; faster than the Plac. Carbohydrate drinks caused comparable plasma glucose values that were significantly higher during refueling and at the end of exercise, compared to Plac. The data suggest that although carbohydrate drinks help to maintain plasma glucose at a higher level, no differences in performance could be detected after glycogen-depleting exercise.