ATP-MgCl2 restores renal microcirculation following trauma and severe hemorrhage.

Although ATP-MgCl2 enhances the recovery of renal function after ischemia and reperfusion, it is not known whether this agent has any beneficial effects on renal microcirculation and function in a nonheparinized model of trauma and severe hemorrhage. To study this, a midline laparotomy was performed (i.e., trauma induced) and the rats were bled to and maintained at a mean arterial pressure of 40 mmHg (1 mmHg = 133.32 Pa) until 40% of the maximum shed blood volume was returned in the form of Ringer's lactate (RL) solution. Animals were then resuscitated with 4 times the volume of the shed blood in the form of RL. ATP-MgCl2, 50 mumol/kg body weight, or an equivalent volume of saline, was infused intravenously during and following resuscitation. Renal microcirculation was examined by using colloidal carbon infusion and laser Doppler flow-metry. Glomerular filtration rate (GFR) was assessed with [3H]inulin clearance and cardiac output (CO) was determined by dye dilution technique. The results indicate that the depressed renal microcirculation following hemorrhage and resuscitation was restored by ATP-MgCl2 treatment. GFR was significantly higher in ATP-MgCl2-treated than saline-treated rats. ATP-MgCl2 also increased urine output, restored the decreased CO, and prevented the occurrence of renal edema after hemorrhage and resuscitation. Thus, ATP-MgCl2 appears to be a useful adjunct to crystalloid resuscitation following trauma and severe hemorrhagic shock even in the absence of blood resuscitation.     

Iron-histidine resonance raman band of deoxyheme proteins: effects of anharmonic coupling and glass-liquid phase transition

Weak anharmonic coupling of two soft molecular vibrations is shown to cause pronounced temperature dependence of the corresponding resonance Raman bands. The developed theory is used to interpret the temperature dependence of the iron-histidine band of deoxyheme proteins and model compounds. It is shown that anharmonic coupling of the iron-histidine and heme doming vibrations must cause pronounced broadening of the band, its asymmetry, and shift of its maximum to the red upon heating. It also can lead to a structured shape of this band at room temperature. Proper consideration of the anharmonic coupling allows simulation of the temperature dependence of the iron-histidine band shape of horse heart myoglobin in the temperature interval of 10-300 K, using the minimum number of necessary parameters. Analysis of this temperature dependence clearly shows that the iron-histidine band of deoxyheme proteins is sensitive to the glass-liquid phase transition in the protein hydration shell, which takes place at 160-190 K.     

L-Arginine restores splenocyte functions after trauma and hemorrhage potentially by improving splenic blood flow

Several studiesindicate that immune responses are markedly depressed early after onsetof hemorrhage. Decreased organ blood flow has been implicated in thepathophysiology of altered immune responses after trauma-hemorrhage. Inthis regard, administration ofL-arginine has been shown torestore depressed intestinal and hepatic blood flow aftertrauma-hemorrhage, probably due to provision of substrate forconstitutive nitric oxide synthase (cNOS). It remains unknown, however,whether administration ofL-arginine also amelioratesdepressed splenic blood flow and whether this agent has any salutaryeffects on depressed splenocyte functions after trauma-hemorrhage. Malerats underwent sham operation or laparotomy and were bled to andmaintained at a mean arterial blood pressure of 40 mmHg until 40% ofmaximum shed blood volume (MBV) was returned as Ringer lactate (RL).Hemorrhaged rats were then resuscitated with RL (4 times MBV over 1 h).During resuscitation, rats received 300 mg/kgL-arginine or saline (vehicle)intravenously; 4 h later, splenic blood flow, splenocyte proliferation,and splenocyte interleukin (IL)-2 and IL-3 were determined.Administration of L-arginineimproved depressed splenic blood flow and restored depressed splenocytefunctions after trauma-hemorrhage. Therefore, provision ofL-arginine during resuscitationafter trauma-hemorrhage should be considered a novel and safe approachfor improving splenic organ blood flow and depressed splenocytefunctions under such conditions.

     

Envelope diversity, characteristics of V3 region and predicted co-receptor usage of human immunodeficiency viruses infecting north indians

Subtypes of human immunodeficiency virus type 1 circulating in 21 north Indian patients were characterized based on the partial sequence of the gp120 envelope protein. A majority of viruses (85.7%, 18/21) were subtype C, while 14.3% (3/21) were subtype A. Sequence analysis revealed that the V3 region was highly conserved compared with V4 and V5. The predicted use of co-receptors indicated exclusive usage of R5, except for two subtype A viruses (AIIMS279 and AIIMS281). Our results demonstrate conservation within the V3 loop of subtype C viruses, and suggest the emergence of non-clade C viruses in the north Indian population.