Ongoing and stimulus-evoked activity of sympathetically correlated neurons in the intermediate zone and dorsal horn of acutely spinalized rats

We have shown previously that in the acutely spinalized anesthetized rat the activities of many dorsal horn interneurons (DHN) at the T(10) level are correlated positively with both ongoing and stimulus-evoked renal sympathetic nerve activity (RSNA) and therefore may belong to networks generating RSNA after acute, cervical, spinal transection. In the present study, we recorded from both DHN and interneurons in the intermediate zone (IZN) of the T(10) spinal segment in acutely C(1)-transected, chloralose-anesthetized, artificially respired rats. The activities of a similar percentage of IZN and DHN were correlated positively with ongoing RSNA, but the peaks of spike-triggered averages of RSNA based on the activity of IZN were larger, relative to dummy averages, than spike-triggered averages of RSNA based on the activity of DHN. Sympathetically correlated DHN and IZN differed in their responses to noxious somatic stimuli. Most correlated DHN had relatively simple somatic fields; they were excited by noxious stimulation of the T(10) and nearby dermatomes and inhibited by stimulation of more distal dermatomes. As we have shown previously, the excitatory and inhibitory fields of these neurons were very similar to fields that, respectively, excited and inhibited RSNA. On the other hand, the somatic fields of 50% of sympathetically correlated IZN were significantly more complex, indicating a difference between either the inputs or the processing properties of IZN and DHN. Sympathetically correlated IZN and DHN also differed in their responses to colorectal distension (CRD), a noxious visceral stimulus. CRD increased RSNA in 11/15 rats and increased the activity of most sympathetically correlated T(10) IZN. On the other hand, CRD decreased the activity of a majority of sympathetically correlated T(10) DHN. These observations suggest that the same stimulus may differentially affect separate, putative, sympathoexcitatory pathways, exciting one and inhibiting the other. Thus the magnitude and even the polarity of responses to a given stimulus may be determined by the modality and location of the stimulus, the degree to which multiple pathways are affected by the stimulus, and the ongoing activity of presympathetic neurons, at multiple rostrocaudal levels, before stimulation. A multipathway system may explain the variability in autonomic responses to visceral and somatic stimuli exhibited in spinally injured patients.     

Simple high-performance liquid chromatographic method to analyze serum creatinine has several advantages over the Jaffé picric acid reaction as demonstrated with a cimetidine dose response in rhesus monkeys

The reversed-phase HPLC methods were developed to determinate the covalently bound protein adducts of the novel anti-cancer drug 5,6-dimethylxanthenone-4-acetic acid (DMXAA) via its glucuronides after releasing aglycone by alkaline hydrolysis in human plasma and human serum albumin (HSA). An aliquot of 75 microl of the mixture was injected onto a Spherex C18 column (150x4.6 mm; 5 microm) at a flow-rate of 2.5 ml/min. The mobile phase comprising of acetonitrile:10 mM ammonium acetate buffer (24:76, v/v, pH 5.8) was used in an isocratic condition, and DMXAA was detected by fluorescence. The method was validated with respect to recovery, selectivity, linearity, precision, and accuracy. Calibration curves for DMXAA were constructed in the concentration range of 0.5-40 microM in washed blank human plasma or HSA prior to alkaline hydrolysis. The difference between the theoretical and calculated concentration and the relative standard deviation were less than 10% at all quality control (QC) concentrations. The limit of detection for the covalent adduct in human plasma or HSA is 0.20 microM. The methods presented good accuracy, precision and sensitivity for use in the preclinical and clinical studies.     

Enduring effects of prenatal cocaine administration on emotional behavior in rats

The present studies sought to determine whether prenatal cocaine administration (15 mg/kg b.i.d. between gestational ages 1-20) had enduring effects on emotional behavior of rats. Rats prenatally treated with cocaine interacted less with other rats in the social interaction test of anxiety at both 30 and 120 days of age. However, there were no differences in the elevated plus maze test of anxiety. Rats prenatally treated with cocaine were significantly more immobile in the forced-swim test at 60 and 120 days of age. In addition, animals exposed to prenatal cocaine were more sensitive to the enhancing effect of phencyclidine (2.0 mg/kg) on startle responses to an acoustic stimulus. The cocaine-treated animals tested at 50 to 60 days of age showed higher levels of prepulse inhibition, in comparison to the saline group, after vehicle pretreatment, but not after phencyclidine. Although there were gender differences in the expression of some of these behavioral tasks, there were no gender differences in the effects of cocaine. These findings indicate that when emotional behavior is altered by prenatal cocaine administration, the effects are enduring.     

Baroreceptor and somatic sensory regulation of kidney function in two-kidney, one-clip Goldblatt hypertensive rats.

The aim of this investigation was to characterize the renal haemodynamic and tubular responses to somatic afferent nerve stimulation following the removal of afferent nerve input from the atria or the carotid sinuses in chloralose-urethane-anaesthetized Sprague-Dawley rats and two-kidney, one-clip Goldblatt hypertensive rats. Bilateral stimulation of the brachial nerve plexi at 15 V, 1.3 Hz for 0.2 ms resulted in an increase in systemic blood pressure in each group of 10-40%, while renal perfusion pressure was maintained at a constant level. There were significantly larger falls in left renal blood flow and combined left and right glomerular filtration rate in all groups following selective denervation of either the cardiopulmonary or the carotid sinus baroreceptors, respectively. Brachial nerve stimulation decreased urine flow rate and absolute and fractional sodium excretion from both kidneys in Sprague-Dawley intact animals by 53, 65 and 59%; in vagotomized animals by 68, 77 and 63%; and in carotid sinus denervated animals by 86, 90 and 48%, respectively. The renal response in the Goldblatt group were similar to the normotensive group, but the main contribution of the total response was from the untouched left kidney. The inhibitory influence of the vagus and carotid sinuses on the renal sympathetic nerve-mediated sodium and water resorption appeared to be enhanced in the Goldblatt hypertensive rats when compared with the normotensive rats. The renal functional responses to somatic afferent nerve stimulation appeared to be well preserved in the renovascular hypertensive rats, although there were important differences in the contributions to the responses from the left and right kidneys. Furthermore, the baroreceptors exerted a greater influence on basal renal function in the hypertensive rats.     

Malignant ameloblastoma,spindle cell variant

In this report, we document the histologic and clinical features of a previously undefined spindle cell variant of ameloblastoma that eventually behaved in a malignant fashion during a protracted course. The predominant histologic pattern was a well-differentiated, cellular, spindled epithelial proliferation arising in the maxilla of a 14-year-old African American girl. Over 19 years, the patient experienced numerous local recurrences, metastases to distant bones after 15 years, and finally bulky local recurrence with intracranial extension resulting in death. This ameloblastic malignancy histologically simulates a low-grade true sarcoma or an ameloblastic sarcoma, but differs in that the extensive spindle cell proliferation is epithelial, characterized by strong cytokeratin immunoreactivity and negative vimentin staining.     

Decreased lung capillary blood volume post-exercise is compensated by increased membrane diffusing capacity

The diffusing capacity of the lung for carbon monoxide (DLCO) decreases to below the pre-exercise value in the hours following a bout of intense exercise. Two mechanisms have been proposed: (1) development of pulmonary oedema and (2) redistribution of central blood volume to peripheral muscles causing a reduction in pulmonary capillary blood volume (V_c). In the present study DLCO, V_c and the membrane diffusing capacity (D_m) were measured in nine healthy females using a rebreathing method, in contrast to the single breath technique employed in previous studies. DLCO, V_c and D_m were measured before and at 1, 2, 3, 16 and 24 h following maximal treadmill exercise. Compared with pre-exercise values, DLCO was depressed by up to 8.9 (3.0)% (P<0.05) for the first 3 h following exercise, but had returned to pre-exercise values by 16 h post-exercise. V_c fell by 21.2 (4.1)% (P<0.05) at 3 h post-exercise, but at the same time D_m increased by 14.7 (9.1)%. It was concluded that: (1) the increase in D_m made it unlikely that the fall in DLCO was due to interstitial oedema and injury to the blood gas barrier; (2) on the other hand, the reduction in DLCO following exercise was consistent with a redistribution of blood away from the lungs; and (3) the trend for D_m and V_c to reciprocate one another indicates a situation in which a fall in V_c nevertheless promotes gas transfer at the respiratory membrane. It is suggested that this effect is brought about by the reorientation of red blood cells within the pulmonary capillaries following exercise.     

Closed Incision Negative Pressure Wound Therapy for Elective Hip and Knee Arthroplasty: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BackgroundPersistent wound drainage after total joint arthroplasty (TJA) increases the risk of surgical site infections (SSIs). Closed incision negative pressure wound therapy (ciNPWT) decreases infections in traumatic wounds, but evidence for its use after elective TJA is limited. The purpose of this meta-analysis of level I studies is to determine the effect of ciNPWT on risk of SSI and wound complications following TJA.MethodsMEDLINE, EMBASE, CINAHL, and Cochrane Library were searched for randomized controlled trials comparing ciNPWT vs standard dressings after total hip (THA) and total knee arthroplasty (TKA). Studies exclusively involving THA for femoral neck fractures were excluded. Risk of SSI and noninfectious wound complications (blisters, seroma, hematoma, persistent drainage, dehiscence, and wound edge necrosis) following TJA were analyzed.ResultsSSI risk was lower with ciNPWT compared to standard dressings (3.4% vs 7%; relative risk [RR] 0.48, P = .007), specifically in revision THA and TKA (4.1% vs 10.5%; RR 0.41, P = .03). ciNPWT increased the noninfectious complication risk after primary TKA (RR 4.71, P < .0001), especially causing wound blistering (RR 12.66, P < .0001). ciNPWT decreased hospital length of stay by 0.73 days (P = .04) and reoperation rate (RR 0.28, P = .01).ConclusionciNPWT decreases SSI risk compared to standard dressings after revision TJA, but not primary TJA. ciNPWT is associated with >12-fold increased risk of wound blistering after primary TKA. ciNPWT plays a role in revision TJA management, but additional randomized controlled trials with uniform wound assessment methods must be performed to sufficiently power findings and draw conclusions on the use of ciNPWT after primary TJA.