[Detection of human papillomavirus DNA sequence in esophageal carcinoma using polymerase chain reaction]

Human Papillomavirus (HPV) DNA sequence in 68 paraffin-embedded specimens of esophageal carcinoma collected from high-risk Shantou City was detected and typed by polymerase chain reaction (PCR) technique. The results showed a 66.18% (45/68) positive rate of HPV DNA. Among these esophageal carcinoma specimens, 44 out of the 45 positive specimens were squamous cell carcinoma and one was adenosquamous carcinoma. The HPV DNA types detected were mostly HPV-6, -11, and -16. HPV-6 DNA was found in 19 (27.94%) of the 68 specimens, HPV-11 DNA in 25 (36.76%) and HPV-16 in 19 (27.94%) specimens. Among these three types, the difference gave no statistical significance (P > 0.05). But HPV-18 DNA was detected in only 6 (8.82%) specimens and the HPV in other 6 specimens was unidentified. It should be noted that as many as 24 (53.33%) of the 45 positive cases had multi-infection (coinfection of 2 or 3 types). Our results suggested that a higher detectable rate of HPV DNA was found in Shantou City as a high-risk region and that HPVs might be closely associated with the pathogenesis of the esophageal carcinoma.

[A seroepidemiological survey: antibody to HTLV-1 in sera from various populations in Guangdong Province]

A seroepidemiological survey of HTLV-1 infection in Guangdong Province was reported. 2224 serum samples from various populations were collected and antibodies to HTLV-1 in sera were detected with indirect immunofluorescent assay. Total seropositive rate was 1.57% (35/2224). The antibody positive rates of HTLV-1 in sera from healthy individuals (n = 1810), blood donors (n = 248), patients with T cell leukemia (n = 109) and patients with neurological diseases (n = 57) were 1.27%, 0.40 %, 7.30% and 5.26% respectively. There was a significant difference between the patients with T cell leukemia and the healthy individuals (P<0.005).

The Campylobacter jejuni porin trimers pack into different lattice types when reconstituted in the presence of lipid

Purified major outer membrane protein of Campylobacter jejuni exhibited different classes of molecules by SDS/PAGE and immunoblotting. A high-molecular-mass product (120-140 kDa) was observed under mild conditions of solubilization, a folded monomeric form of 35 kDa was seen when treated at high SDS concentrations and finally, a single band around 45 kDa occurred when the sample was heated to 96 degrees C [Bolla, J. M., Loret, E., Zalewski. M. & Pages, J. M. (1995) J. Bacteriol. 177, 4266-4271]. The high-molecular-mass product was reconstituted into two-dimensional crystals in the presence of phospholipids and Mg2+. The C. jejuni porin required different conditions for successful reconstitution into two-dimensional crystals than the Escherichia coli porin OmpF. Electron microscopy and digital image processing of negatively stained specimens revealed a rectangular lattice with a unit cells size of a = 8.9 nm, b = 14.9 nm, an oblique lattice with a = 8.9 nm, b = 30.1 nm, gamma = 98 degrees, and a trigonal lattice with a = b = 9.6 nm. Projection maps were calculated to a resolution of 2 nm, and exhibited a trimeric protein with three stain-filled indentations.

Dantrolene, an inhibitor of intracellular calcium release, fails to increase survival in a rat model of intra-abdominal sepsis

OBJECTIVE

Increased release of intracellular calcium has been implicated in cell death and organ failure in endotoxemia and sepsis. We sought to test this hypothesis in a rat model of antibiotic-treated intraperitoneal sepsis with the use of dantrolene sodium, a specific inhibitor of intracellular calcium release.

DESIGN

A prospective, randomized controlled trial.

SETTING

An experimental animal laboratory in a university hospital.

SUBJECTS

Two hundred fourteen male Sprague-Dawley rats.

INTERVENTIONS

Rats were rendered septic by intraperitoneal implantation of sterile feces mixed with live Escherichia coli and allocated to control, vehicle, or dantrolene treatment. A separate group of rats had arterial catheters implanted to allow blood sampling for determination of circulating tumor necrosis factor (TNF)-alpha and lactate concentrations. Additional rats were randomized to receive vehicle or dantrolene after intravenous injection of endotoxin.

MEASUREMENTS AND MAIN RESULTS

Over the 7-day study period, survival was significantly worse among rats that received dantrolene at a dose of 10 mg/kg, irrespective of whether treatment was started before or after induction of peritonitis. Mean whole blood lactate for each group peaked at 6 hrs after induction of infection. There were no significant differences in lactate concentration among the groups at any of the time points examined. Similarly, there were no differences among any of the groups for circulating concentrations of TNF-alpha. In rats challenged with endotoxin, dantrolene affected neither survival nor circulating concentrations of TNF-alpha.

CONCLUSIONS

We conclude that dantrolene decreases survival in bacterial sepsis and has no effect on survival in endotoxemia in rats. The importance of excessive intracellular calcium release in sepsis remains to be elucidated.

Breathing and brain blood flow during sleep in patients with chronic mountain sickness

Chronic mountain sickness (CMS) patients have lower arterial O2 saturation (SaO2) during sleep compared with healthy high-altitude residents, but whether nocturnal arterial O2 content (CaO2) and brain O2 delivery are reduced is unknown. We measured SaO2, CaO2, sleep-disordered breathing (SDB), and internal carotid artery flow velocity in 8 CMS patients, 8 age-matched healthy CMS controls, 11 healthy younger-aged Han, and 11 healthy younger-aged Tibetan male residents of Lhasa, Tibet (3,658 m). CMS patients spent a greater portion of the night in SDB (total no. of episodes of apnea, hypopnea, and hypoventilation) than did the CMS controls, young Han, or young Tibetans (15% vs. 5, 1, and 1%, respectively; P < 0.05) because of more frequent apnea and hypoventilation episodes and longer duration of all types of episodes. SDB and unexplained arterial O2 desaturation caused nocturnal SaO2 to be lower and more variable in CMS patients than in CMS controls or in younger-aged Han or Tibetan men. Average CaO2 was similar, but the CMS patients spent 29%, whereas the other groups spent < 4%, of the night at values < 18 ml O2/100 ml whole blood. Internal carotid artery flow velocity during wakefulness was similar in CMS patients and CMS controls despite higher end-tidal PcO2 values in the CMS patients. When contiguous sleep stages are compared, flow velocity rose from stage 2 to rapid-eye-movement sleep in both groups. Whereas flow velocity remained elevated from awake to rapid-eye-movement sleep in the CMS controls, it fell in the CMS patients. During episodes of SDB, internal carotid flow velocity increased in CMS controls but did not change in the CMS patients such that values were lower in the CMS patients than in CMS controls at the end and after SDB episodes. We concluded that SDB and episodes of unexplained desaturation lowered nocturnal SaO2 and CaO2, which, together with a lack of compensatory increase in internal carotid artery flow velocity, likely decreased brain O2 delivery in CMS patients during a considerable portion of the night.

Effect of human hemoglobin on systemic and regional hemodynamics in a porcine model of endotoxemic shock

OBJECTIVE

Excessive release of nitric oxide has been implicated as being an important factor contributing to systemic arterial hypotension in septic shock. Hemoglobin is an effective nitric oxide scavenger. The purpose of this study was to test the hypothesis that treatment with cross-linked human hemoglobin can ameliorate systemic arterial hypotension and improve organ perfusion in a porcine model of normodynamic endotoxemic shock.

DESIGN

Prospective, randomized, controlled trial.

SETTING

Laboratory at a university medical center.

SUBJECTS

Fourteen, male, random-bred swine.

INTERVENTIONS

All animals were challenged with Escherichia coli lipopolysaccharide (400 microg/kg) infused from t = 0 to 90 mins. Pigs in group 1 (n = 7) were infused with cross-linked human hemoglobin (150 mg/kg) at t = 30 mins. Pigs in group 2 (n = 7) were infused at t = 30 mins with 150 mg/kg of dextran (average molecular weight 70,000 daltons) as a 5% (weight per volume) solution.

MEASUREMENTS AND MAIN RESULTS

After infusion of endotoxin, mean arterial pressure decreased significantly (p < .05) but baseline cardiac index was maintained in both groups. In hemoglobin-treated pigs (group 1), mean arterial pressure was higher than in controls (group 2) from t = 60 to 120 mins (p < .05). There were no significant differences between the two groups in systemic vascular resistance index, renal blood flow, mesenteric blood flow, systemic oxygen delivery, or systemic oxygen extraction. Ileal mucosal blood flow was lower (p < .07) in group 1 than in group 2. Mean pulmonary arterial pressure increased relative to baseline in both groups, but was significantly greater in group 1 as compared with group 2. Compared with controls, infusion of hemoglobin significantly exacerbated endotoxin-induced arterial hypoxemia (p < .05).

CONCLUSIONS

Treatment with hemoglobin improved mean arterial pressure in endotoxemic swine without significantly impairing blood flow to the renal or mesenteric vascular beds. Infusion of hemoglobin, however, significantly exacerbated endotoxin-induced pulmonary hypertension and arterial hypoxemia. Additional pharmacologic strategies may be necessary to ameliorate the potential adverse pulmonary effects of administering hemoglobin solutions to patients with sepsis.

A selective inhibitor of inducible in nitric oxide synthase prolongs survival in a rat model of bacterial peritonitis: comparison with two nonselective strategies

We evaluated the effects on survival of three different strategies for blocking the actions of nitric oxide (NO) during Gram-negative sepsis in rats. Male Sprague-Dawley rats underwent placement of a jugular vein catheter and i.p. implantation of a gelatin capsule containing a paste (.11 +/- 0.1 g final weight) consisting of sterile rat feces mixed with a suspension (.2 mL) of viable Escherichia coli (strain sm 18; 5.7 x 10(5) colony-forming units) in saline. Beginning at T = 6h, all animals received i.v. ampicillin (85 mg/kg every 12 h) until death or the administration of five doses. At the same time points, pairs of animals received an i.v. dose of either an experimental treatment agent or an appropriate control substance. The following experimental regimens were tested: 5 mg/kg per dose of S-methylisothiourea sulfate (SMT), a selective inhibitor of the inducible isoform of nitric oxide synthase (NOS); 10 mg/kg per dose or 25 mg/kg per dose of NG-nitro-L-arginine methyl ester (L-NAME), an inhibitor of the inducible and constitutive isoforms of NOS; 200 mg/kg per dose of cross-linked human hemoglobin (HGB), an NO scavenger. SMT significantly prolonged survival in septic rats, although cumulative survival at T = 168 h was approximately equivalent in SMT- or saline-treated animals. In contrast, HGB and the higher dose of L-NAME significantly shortened survival times. At T = 20 h, arterial PO2 was significantly lower in rats treated with HGB as compared to time-matched controls. We conclude that SMT, a compound with reported activity as a selective inhibitor of the inducible isoform of NOS, prolongs survival in a rat model of antibiotic-treated Gram-negative sepsis.

The effect of lesion volume on cerebral vasomotor tone after focal brain injury and shock

We have previously shown that the volume of a focal brain injury influences cerebral blood flow. We hypothesized that the cerebral vasomotor tone after traumatic brain injury and shock is related to lesion volume and that the size of the lesion would affect vasomotor reactivity. Swine were randomized to receive either a large or small cryogenic injury followed by shock, and were studied for 5 h postresuscitation. A small brain injury and shock produced a significant and sustained increase in bihemispheric pial arteriolar diameter when compared to the large lesion group and controls. A large brain injury and shock resulted in a significant decrease in the pial arteriolar diameter in the injured hemisphere. We also noted significant differences between and within groups in interhemispheric pial arteriolar diameter and pial arteriolar reactivity to acetylcholine and hypocarbia. These data suggest that the volume of injured tissue influences cerebral blood flow by a vascular mechanism, which may be due in part to an alteration in cerebral endothelial cell function.

Substitution of arginine for glycine at position 154 of the alpha 1 chain of type I collagen in a variant of osteogenesis imperfecta: comparison to previous cases with the same mutation

A substitution of arginine for glycine at amino acid position 154 of the alpha 1(I) collagen chain was found in a father and his three children. The phenotype of the patients includes manifestations of types I and III/IV osteogenesis imperfecta, but appears to be milder than that of the previously described two unrelated patients that had the identical mutation in the alpha 1(I) collagen chain. The variability in the phenotype raises the possibility of epistatic loci or environmental effects on expression of the disorder.

Smaller alveolar-arterial O2 gradients in Tibetan than Han residents of Lhasa (3658 m)

Previous studies have indicated that native Tibetans have a larger lung capacity and better maintain arterial O2 saturation during exercise than Han ("Chinese") acclimatized lowlanders. To test if differences in ventilation or alveolar-arterial O2 gradient (A-aDO2) were responsible, we compared 10 lifelong Tibetan and 9 Han acclimatized newcomer residents of Lhasa (3658 m) at rest and during progressive exercise. Resting blood gas tensions and arterial O2 saturation in the two groups were similar. During exercise the Tibetans had lower total ventilation and higher arterial CO2 tensions than the Han (both P < 0.01) and markedly lower A-aDO2 (7 +/- 1 vs. 11 +/- 1, 13 +/- 1 vs. 18 +/- 1, and 14 +/- 1 vs. 20 +/- 1 mmHg at light, medium, and heavy workloads respectively, all P < 0.01). The Tibetans' narrower A-aDO2 compensated for their lower exercise ventilation such that arterial O2 tension and saturation were raised above acclimatized newcomer values and better maintained during exercise. We concluded that the Tibetans exhibited more efficient pulmonary gas exchange which compensated for reduced ventilation and lessened respiratory effort.

Direct sequencing of PCR products derived from cDNAs for the pro alpha 1 and pro alpha 2 chains of type I procollagen as a screening method to detect mutations in patients with osteogenesis imperfecta

More than 150 mutations in the genes for type I procollagen have been found in unrelated patients with osteogenesis imperfecta (OI), but mutations have been difficult to define in many patients with the mildest forms of the disease. Here, we have used robotically automated sequencing of the cDNAs for type I procollagen to screen for mutations in 12 patients suspected of having nonlethal OI (types I, III, and IV). Single base mutations that changed codons for obligate glycine residues were found in seven of the patients. Altogether, we analyzed 4,379 bp of sequences of both alleles of the pro alpha 1 (I) collagen (8,758 bp of allelic sequences) and 4,200 bp of sequences of both alleles of the pro alpha 2(I) collagen (8,400 bp of allelic) from each patient.

Arterial oxygen saturation in Tibetan and Han infants born in Lhasa, Tibet

BACKGROUND

Reduced oxygen availability at high altitude is associated with increased neonatal and infant mortality. We hypothesized that native Tibetan infants, whose ancestors have inhabited the Himalayan Plateau for approximately 25,000 years, are better able to maintain adequate oxygenation at high altitude than Han infants, whose ancestors moved to Tibet from lowland areas of China after the Chinese military entered Tibet in 1951.

METHODS

We compared arterial oxygen saturation, signs of hypoxemia, and other indexes of neonatal wellbeing at birth and during the first four months of life in 15 Tibetan infants and 15 Han infants at 3658 m above sea level in Lhasa, Tibet. The Han mothers had migrated from lowland China about two years previously. A pulse oximeter was placed on each infant's foot to provide measurements of arterial oxygen saturation distal to the ductus arteriosus.

RESULTS

The two groups had similar gestational ages (about 38.9 weeks) and Apgar scores. The Han infants had lower birth weights (2773 +/- 92 g) than the Tibetan infants (3067 +/- 107 g), higher concentrations of cord-blood hemoglobin (18.6 +/- 0.8 g per deciliter, vs. 16.7 +/- 0.4 in the Tibetans), and higher hematocrit values (58.5 +/- 2.4 percent, vs. 51.4 +/- 1.2 percent in the Tibetans). In both groups, arterial oxygen saturation was highest in the first two days after birth and was lower when the infants were asleep than when they were awake. Oxygen saturation values were lower in the Han than in the Tibetan infants at all times and under all conditions during all activities. The values declined in the Han infants from 92 +/- 3 percent while they were awake and 90 +/- 5 percent during quiet sleep at birth to 85 +/- 4 percent while awake and 76 +/- 5 percent during quiet sleep at four months of age. In the Tibetan infants, oxygen saturation values averaged 94 +/- 2 percent while they were awake and 94 +/- 3 percent during quiet sleep at birth and 88 +/- 2 percent while awake and 86 +/- 5 percent during quiet sleep at four months. Han infants had clinical signs of hypoxemia--such as cyanosis during sleep and while feeding--more frequently than Tibetans.

CONCLUSIONS

In Lhasa, Tibet, we found that Tibetan newborns had higher arterial oxygen saturation at birth and during the first four months of life than Han newborns. Genetic adaptations may permit adequate oxygenation and confer resistance to the syndrome of pulmonary hypertension and right-heart failure (subacute infantile mountain sickness).

EUK-8, a synthetic superoxide dismutase and catalase mimetic, ameliorates acute lung injury in endotoxemic swine

Reactive oxygen metabolites are believed to be important mediators of sepsis- or lipopolysaccharide (LPS)-induced adult respiratory distress syndrome. EUK-8 is a novel, synthetic, low-molecular-weight salen-manganese complex that exhibits both superoxide dismutase and catalase activities in vitro. We hypothesized that treatment with EUK-8 would ameliorate pulmonary dysfunction in a porcine model of LPS-induced adult respiratory distress syndrome. At T = -18 h, pigs received an intravenous priming dose of LPS (20 micrograms/kg). Anesthetized ventilated swine were randomized to receive 1) no further treatment (n = 5); 2) LPS (250 micrograms/kg from T = 0 to 60 min, n = 6); 3) LPS and a low dose of EUK-8 (10-mg/kg bolus at T = -15 min and 1 mg/kg.h from T = 0 to 240 min, n = 6) or 4) LPS and a higher dose of EUK-8 (10-mg/kg bolus and 3 mg/kg.h, n = 6). Treatment with EUK-8, particularly at the higher dose, significantly attenuated many of the features of LPS-induced acute lung injury, including arterial hypoxemia, pulmonary hypertension, decreased dynamic pulmonary compliance and pulmonary edema. LPS caused an increase in lung tissue malondialdehyde content that was abrogated in both EUK-8-treated groups. EUK-8 treatment had no effect on circulating plasma levels of tumor necrosis factor-alpha, thromboxane B2 or 6-keto-prostaglandin F1 alpha. We conclude that EUK-8 prevents many of the manifestations of LPS-induced adult respiratory distress syndrome in pigs by detoxifying reactive oxygen metabolites without affecting the release of other important proinflammatory mediators.

Hypoxic ventilatory responses in Tibetan residents of 4400 m compared with 3658 m

Lifelong Tibetan residents of 3658 m ventilate as much and have hypoxic and hypercapnic ventilatory responsiveness as least as great as acclimatized newcomers, and likely greater than lifelong North or South American high-altitude residents. To determine whether Tibetans residing at altitudes > 3658 m maintained similar levels of ventilation, hypoxic and hypercapnic ventilatory responses, we transported 20 lifelong residents of > or = 4400 m to 3658 m for comparison with 27 similarly-aged male Tibetan residents of 3658 m. At 3658 m, the 4400 m compared with the 3658 m Tibetans had similar levels of minute ventilation and arterial O2 saturation, higher respiratory quotients but lower hypoxic ventilatory responses. We conclude that Tibetan residents of > or = 4400 m ventilate as much as Tibetan residents of 3658 m despite an altitude-associated blunting of their hypoxic ventilatory responses. Thus, factors other than hypoxic ventilatory chemosensitivity are likely to be important contributors to resting ventilation among Tibetan high altitude residents.

Protective effects of a novel 32-amino acid C-terminal fragment of CAP18 in endotoxemic pigs

BACKGROUND

Cationic antimicrobial protein of 18 kd (CAP18) is a neutrophil-derived peptide that binds lipopolysaccharide (LPS) with high affinity. We hypothesized that CAP18(106-137), a novel synthetic 32-amino acid C-terminal fragment of CAP18, would neutralize the physiologic derangements induced by LPS in anesthetized swine.

METHODS

Pigs were randomly allocated into three groups. Those in the LPS group (n = 6) were infused with LPS (3 micrograms/kg/hr for 4 hours). Pigs in the LPS/CAP18 group (n = 6) were challenged with LPS (3 micrograms/kg/hr for 4 hours) and also treated with CAP18(106-137) (4 mg/kg/hr for 4 hours). Pigs in the RL group (n = 4) received neither LPS nor CAP18(106-137).

RESULTS

Treatment with CAP18(106-137) blocked LPS-induced increases in plasma levels of 6-keto-prostaglandin F1 alpha and tumor necrosis factor-alpha and prevented LPS-induced changes in cardiac output, arterial PO2, phagocyte activation, and peripheral leukocyte count. Changes in circulating concentrations of thromboxane B2, mean pulmonary artery pressure, and dynamic pulmonary compliance were attenuated in the LPS/CAP18 group.

CONCLUSIONS

Treatment with CAP18(106-137) neutralizes many of the deleterious effects of LPS in pigs.

Colloid infusion after brain injury: effect on intracranial pressure, cerebral blood flow, and oxygen delivery

OBJECTIVES

We sought to determine the effects of colloid osmotic pressure on cerebral edema formation after brain injury. We hypothesized that an increase in plasma oncotic pressure accompanying a colloid infusion would be associated with a decrease in intracranial pressure and increases in cerebral blood flow and oxygen delivery when compared with isotonic crystalloid.

DESIGN

Prospective, laboratory study.

SETTING

University surgical research laboratory.

SUBJECTS

Adult swine, both genders.

INTERVENTIONS

Cryogenic brain injury with intravenous fluid infusion of either lactated Ringer's solution or 6% dextran-70 in normal saline. The effect of this intervention was monitored for 24 hrs.

MEASUREMENTS

Mean arterial pressure, central venous pressure, intracranial pressure, hemoglobin concentration, plasma oncotic pressure, serum osmolality, cerebral blood flow, and specific gravity of cortical biopsies.

RESULTS

Cryogenic injury significantly increased the cortical water content and the intracranial pressure and significantly decreased the cerebral blood flow and oxygen delivery (p < .05). Dextran infusion significantly increased the colloid oncotic pressure. There were no differences between the lactated Ringer's solution and dextran groups in intracranial pressure, cerebral oxygen delivery, or cortical water content after 24 hrs.

CONCLUSIONS

Colloid infusion after a focal cryogenic injury does not increase cerebral oxygen delivery or reduce either cerebral edema formation or intracranial pressure when compared with lactated Ringer's solution. Colloid is not superior to isotonic crystalloid in the management of isolated brain injury.

The effect of hypertonic resuscitation on pial arteriolar tone after brain injury and shock

Acute brain injury followed by hemorrhagic shock (HEM) causes prohibitive mortality in trauma patients because these combined events lead to low cerebral blood flow (CBF) and cerebral oxygen delivery (co2del). Proper treatment therefore requires rapid correction of cerebral perfusion deficits. Previous studies have shown that hypertonic crystalloid resuscitation significantly improves CBF and co2del in a model of brain injury and HEM when compared to lactated Ringer's (LR) solution. The mechanism or mechanisms for this advantage, however, are not well understood. We hypothesized that hypertonic fluid resuscitation would reduce pial arteriolar tone after brain injury and HEM resulting in an increase in CBF when compared to LR resuscitation. We measured cerebral and systemic variables in a porcine model of focal cryogenic brain injury and hemorrhagic shock over a 5-hour period. Swine were randomized to receive either hypertonic sodium lactate (HSL) or LR fluid resuscitation. The HSL resuscitation produced a significant and sustained elevation in cerebral perfusion pressure and pial arteriole diameter (p < 0.05), and a sustained elevation in CBF after brain injury and HEM when compared with LR. These data suggest that hypertonic fluid resuscitation following brain injury and HEM improves CBF, at least in part, by causing vasodilation of cerebral resistance vessels.

The relationship of fluid balance and sodium administration to cerebral edema formation and intracranial pressure in a porcine model of brain injury

BACKGROUND

Fluid and sodium restriction have been advocated after brain injury as a means of controlling intracranial pressure (ICP). Recent clinical data showing no significant relationships between the amount of fluid infused or sodium administered (Na) and ICP question this practice.

OBJECTIVE

To analyze the relationship of amount of fluid, Na, and fluid balance to cerebral edema formation and ICP.

METHODS

A cryogenic brain injury with and without hemorrhagic shock was studied after 24 hours in swine (n = 35) randomized to receive either lactated Ringer's solution (LR) or hypertonic sodium lactate (HSL). Cerebral edema formation as indicated by cortical water content (CWC) was determined by measurement of specific gravity.

RESULTS

There was a significant positive correlation between the following variables: (1) amount of fluid and ICP (r = 0.598; p < 0.01); (2) fluid balance and ICP (r = 0.684; p < 0.01); and (3) free water and ICP (r = 0.614; p < 0.01). There was a significant negative correlation between serum osmolarity and ICP (r = -0.654; p < 0.01). The study failed to demonstrate a significant correlation between Na and ICP, amount of fluid and CWC, or fluid balance and CWC.

CONCLUSIONS

These data suggest that both the volume of fluid infused and the fluid balance do affect the ICP, but the amount of Na infused does not. The lack of a significant correlation between any of the independent variables and CWC suggests that their effect on ICP is not related to cerebral edema formation. These findings, combined with the observed significant positive correlation between free H2O infused and ICP, and the significant negative correlation between serum osmolarity and ICP, suggest that HSL resuscitation increases intracranial compliance after brain injury while LR decreases it. The data also suggest that free water restriction is warranted in patients with head injuries.

Brain edema formation after brain injury, shock, and resuscitation: effects of venous and arterial pressure

BACKGROUND

Recent work suggests that increased intracranial pressure (ICP) following brain injury and shock is related to increased central venous pressure (CVP) following resuscitation.

OBJECTIVE

To analyze the relationship of intravascular pressures to edema formation and ICP in an experimental model.

METHODS

In a porcine model of cryogenic brain injury and hemorrhagic shock, we studied CVP, mean arterial pressure (MAP), ICP, and cortical water content (CWC, as cortical specific gravity) at baseline (BL), 45 minutes after shock (H45), and 1, 3, 6, 12, and 24 hours (H) after resuscitation. Group 1 was the control group, group 2 brain injury only, group 3 shock only, and group 4 brain injury and shock.

RESULTS

Brain injury significantly increased ICP and CWC. Mean arterial pressure significantly correlated with ICP (r = 0.54, p = 0.02) and with CWC (r = -0.48, p = 0.03) in group 4 at 24H but not in the other groups at any time period. There was no significant correlation between CVP and ICP or CWC in any group at any time interval.

CONCLUSIONS

These data suggest that brain edema formation in the injured hemisphere is related to MAP and not CVP, but variability in MAP accounts for only 29% of the variability in CWC and ICP, suggesting the importance of factors other than hydrostatic pressure in determining the amount of edema and the ICP after brain injury. Previous work demonstrating the significant correlation of polymorphonuclear leukocyte infiltration with ICP (r = 0.71, p < 0.001) and with CWC (r = -0.63, p < 0.001) suggests that inflammation may be one of these factors.

RFLP-based phylogenetic analysis of wide compatibility varieties in Oryza sativa L

Twenty-one wide compatibility varieties (WCVs) of rice together with three indica and three japonica testers were assayed with 160 DNA probes that were selected to represent the entire RFLP map at an average interval of 11 cM. On the basis of four enzyme digestion 125 probes detected polymorphisms among the WCVs and subspecies' testers. Among these polymorphic probes there were 68 that could distinguish the indica from the japonica testers. Two dendrograms were constructed on the basis of 398 polymorphic fragments of 125 probes and 139 polymorphic fragments of 68 subspecies' differentiating probes in combination with single enzymes, respectively. The reliability and representativeness of the testers and the levels of DNA variations among WCVs were estimated. The potential of WCVs in the utilization of intersubspecific heterosis is discussed.

Mitochondrial DNA analysis in Tibet: implications for the origin of the Tibetan population and its adaptation to high altitude

Mitochondrial DNAs (mtDNAs) of 54 Tibetans residing at altitudes ranging from 3,000-4,500 m were amplified by polymerase chain reaction (PCR), examined by high-resolution restriction endonuclease analysis, and compared with those previously described in 10 other Asian and Siberian populations. This comparison revealed that more than 50% of Asian mtDNAs belong to a unique mtDNA lineage which is found only among Mongoloids, suggesting that this lineage most likely originated in Asia at an early stage of the human colonization of that continent. Within the Tibetan mtDNAs, sets of additional linked polymorphic sites defined seven minor lineages of related mtDNA haplotypes (haplogroups). The frequency and distribution of these haplogroups in modern Asian populations are supportive of previous genetic evidence that Tibetans, although located in southern Asia, share common ancestral origins with northern Mongoloid populations. This analysis of Tibetan mtDNAs also suggests that mtDNA mutations are unlikely to play a major role in the adaptation of Tibetans to high altitudes.

Autonomic regulation of heart rate response to exercise in Tibetan and Han residents of Lhasa (3,658 m)

To test the hypothesis that native high-altitude residents have less beta-sympathetic and more parasympathetic tone than newcomers, we compared the effects of beta-sympathetic and parasympathetic blockade in 10 Tibetan and 9 Han acclimatized male residents of Lhasa, Tibet Autonomous Region, China (elevation 3,658 m). Each subject was studied during cycle ergometer exercise at 70, 132, and 191 W after placebo (normal saline), beta-sympathetic (propranolol, 0.2 mg/kg iv), or parasympathetic (atropine, 0.04 mg/kg iv) blockade in random order on different days. At rest, the fall in resting heart rate with propranolol and the rise with atropine were equal in Tibetan and Han subjects. During exercise, the fall in heart rate with propranolol relative to placebo values was greater in the Han than in the Tibetan group, whereas the rise in heart rate with atropine was greater in the Tibetans. Propranolol or atropine administration did not change minute ventilation per unit O2 consumption in either group. At the highest level of exercise on the placebo day, the Tibetans achieved a higher work load and level of O2 consumption than the Han subjects. Propranolol or atropine reduced O2 consumption and work load similarly in the two groups at the highest exercise level. The results supported our hypothesis that native Tibetan residents of high altitude exhibit more para-sympathetic and less beta-sympathetic tone during exercise. Neither relatively greater parasympathetic nor less sympathetic activation appeared implicated in the greater exercise capacity of Tibetans compared with that of acclimatized newcomer residents of high altitude.

Effect of lesion volume on cerebral hemodynamics after focal brain injury and shock

Cerebral blood flow (CBF) varies unpredictably in patients after head injury and hemorrhagic shock. Proper treatment requires knowledge of ischemic versus hyperemic flow. The degree to which the size or severity of the injury may contribute to CBF abnormalities is unknown. We hypothesized that lesion size is a determinant of postinjury CBF. We measured cerebral and systemic variables in a porcine model of focal cryogenic brain injury and hemorrhagic shock over a 5-hour period. Swine were randomized to receive either a large or small lesion followed by hemorrhage. In the small lesion group traumatic brain injury, followed by shock and resuscitation, produced a significant and sustained elevation in bihemispheric regional CBF and cerebral oxygen delivery that was significantly greater than that observed in either the large lesion group or the controls (p < 0.05). There were no significant differences between the experimental groups in volume of hemorrhage, intracranial pressure, cerebral perfusion pressure, arterial oxygen content, or PaCO2. These data suggest that the volume of injured tissue may determine post-resuscitation CBF, and that interventions to reduce cerebral blood volume (i.e., hyperventilation) may not be universally applicable in all head injured patients.

The association of leukocytes with secondary brain injury

Shock increases mortality from brain injuries, but the mechanism is poorly understood. We hypothesized that brain injury followed by shock and resuscitation leads to a secondary reperfusion injury mediated in part by polymorphonuclear leukocytes (PMNs). To validate this hypothesis, we studied cerebral perfusion pressure (CPP), intracranial pressure (ICP), cerebral blood flow (CBF), cortical water content (CWC), and hemodynamic variables in a porcine model of focal cryogenic brain injury and hemorrhagic shock. Cerebral PMN accumulation (CPMN) in the injured and uninjured hemispheres was determined histologically from the total PMNs in five high-power fields (400x). Twenty-nine mature swine were randomized to four groups. Group 1, the control group, was instrumented only. Group 2 animals had a brain injury alone and were studied for 24 hours. Group 3 animals had a brain injury and hemorrhagic shock. Group 4 animals had hemorrhagic shock alone. Brain injury followed by shock caused a significantly greater ICP and a significantly lower CBF than brain injury or shock alone. There was no significant difference in CPP between groups after resuscitation. The CWC of the lesioned area was similar in both brain-injured groups but was significantly increased when compared with the controls and the shock-only group. The CWC of the nonlesioned hemisphere was higher in group 3 than in group 2. The CPMN in both hemispheres in group 3 was significantly greater than in either group 2 or group 4. There was a significant positive correlation between CPMN and both ICP and CWC, and a significant negative correlation between CPMN and CBF. These data suggest an association between CPMN accumulation and secondary brain injury.

Sequencing of cDNA from 50 unrelated patients reveals that mutations in the triple-helical domain of type III procollagen are an infrequent cause of aortic aneurysms

Detailed DNA sequencing of the triple-helical domain of type III procollagen was carried out on cDNA prepared from 54 patients with aortic aneurysms. The 43 male and 11 female patients originated from 50 different families and five different nationalities. 43 patients had at least one additional blood relative who had aneurysms. Five overlapping asymmetric PCR products, covering all the coding sequences of the triple-helical domain of type III procollagen, were sequenced with 28 specific sequencing primers. Analysis of the sequencing gels revealed only two nucleotide changes that altered the structure of the protein. One was a substitution of threonine for proline at amino acid position 501 and its functional importance was not clearly established. The other was a substitution of arginine for an obligatory glycine at amino acid position 136. In 40 of the 54 patients, detection of a polymorphism in the mRNA established that both alleles were expressed. The results indicate that mutations in type III procollagen are the cause of only about 2% of aortic aneurysms.

Deletion of 19 base pairs in intron 13 of the gene for the pro alpha 2(I) chain of type-I procollagen (COL1A2) causes exon skipping in a proband with type-I osteogenesis imperfecta

Skin fibroblasts from a proband with mild osteogenesis imperfecta (type I) synthesized normal pro alpha 2(I) chains and shortened pro alpha 2(I) chains of type-I procollagen. The type-I collagen that contained the shortened alpha 2(I) chains was thermally unstable in that it was cleaved at 30 degrees C by a mixture of trypsin and chymotrypsin. The mutation generating the shortened pro alpha 2(I) chains was shown to be a deletion of 19 base pairs from +4 to +22 of intron 13 of the COL1A2 gene by sequencing of genomic DNA and allele-specific oligonucleotide hybridization. The same mutation was found in the proband's affected father. Probe-protection experiments with S1 nuclease demonstrated that about 88% of the RNA transcripts from the mutated allele were spliced by exon skipping from exon 12 to exon 14 and that about 12% of the RNA transcripts were normally spliced. There was no evidence for use of cryptic splice sites, even though two cryptic splice sites had more favorable statistical scores and delta G degree 37 values than the new site that was created by the mutation and that was used for splicing of 12% of the transcripts into a normal mRNA. Comparison of the results with observations on 17 previously reported mutations that produced in-frame deletions of amino acids from the triple-helical domain of type-I collagen indicated that deletions in the N-terminal half of the alpha 2(I) chain tended to produce milder phenotypes than similar deletions elsewhere in the alpha 1(I) or alpha 2(I) chains.

Self-pumped phase conjugation induced by an incoherent beam

An incoherent beam was used to induce the self-pumped phase-conjugate output in a (BaSr) TiO(3) crystal. It was found that, in terms of the alteration of the signal-beam parameters, the induced self-pumped phase-conjugate output could be eliminated or maintained after the incoherent beam was removed. The observed effects were attributed to the local modification of the fanning geometry of the signal beam.

Hypoxic ventilatory responsiveness in Tibetan compared with Han residents of 3,658 m

Lifelong high-altitude residents of North and South America acquire blunted hypoxic ventilatory responses and exhibit decreased ventilation compared with acclimatized newcomers. The ventilatory characteristics of Himalayan high-altitude residents are of interest in the light of their reportedly lower hemoglobin levels and legendary exercise performance. Until recently, Sherpas have been the only Himalayan population available for study. To determine whether Tibetans exhibited levels of ventilation and hypoxic ventilatory drives that were as great as acclimatized newcomers, we compared 27 lifelong Tibetan residents of Lhasa, Tibet, China (3,658 m) with 30 acclimatized Han ("Chinese") newcomers matched for age, body size, and extent of exercise training. During room air breathing, minute ventilation was greater in the Tibetan than in the Han young men because of an increased respiratory frequency, but arterial O2 saturation and end-tidal PCO2 did not differ, indicating similar levels of effective alveolar ventilation. The Tibetan subjects had higher hypoxic ventilatory response shape parameter A values and hypercapnic ventilatory responsiveness than the Han subjects. Among the Han subjects, duration of high-altitude residence correlated with the degree of blunting of the hypoxic ventilatory drive. Paradoxically, hyperoxia (inspired O2 fraction 0.70) increased minute ventilation and decreased end-tidal PCO2 in the Tibetan but not in the Han men. We concluded that lifelong Tibetan residents of high altitude neither hypoventilated nor exhibited blunted hypoxic ventilatory responses compared with acclimatized Han newcomers, suggesting that the effects of lifelong high-altitude residence on ventilation and ventilatory response to hypoxia differ in Tibetan compared with other high-altitude populations.

Minimal hypoxic pulmonary hypertension in normal Tibetans at 3,658 m

Elevated pulmonary arterial pressure in high-altitude residents may be a maladaptive response to chronic hypoxia. If so, well-adapted populations would be expected to have pulmonary arterial pressures that are similar to sea-level values. Five normal male 22-yr-old lifelong residents of > or = 3,600 m who were of Tibetan descent were studied in Lhasa (3,658 m) at rest and during near-maximal upright ergometer exercise. We found that resting mean pulmonary arterial pressure [15 +/- 1 (SE) mmHg] and pulmonary vascular resistance (1.8 +/- 0.2 Wood units) were within sea-level norms and were little changed while subjects breathed a hypoxic gas mixture [arterial O2 pressure (PaO2) = 36 +/- 2 Torr]. Near-maximal exercise [87 +/- 13% maximal O2 uptake (VO2max)] increased cardiac output more than threefold to values of 18.3 +/- 1.2 l/min but did not elevate pulmonary vascular resistance. Breathing 100% O2 during near-maximal exercise did not reduce pulmonary arterial pressure or vascular resistance. We concluded that this small sample of healthy Tibetans with lifelong residence > or = 3,658 m had resting pulmonary arterial pressures that were normal by sea-level standards and exhibited minimal hypoxic pulmonary vasoconstriction, both at rest and during exercise. These findings are consistent with remarkable cardiac performance and high-altitude adaptation.

Internal carotid arterial flow velocity during exercise in Tibetan and Han residents of Lhasa (3,658 m)

Cerebral blood flow increases with acute exposure to high altitude, but the effect of hypoxia on the cerebral circulation at rest and during exercise appears influenced by the duration of high-altitude exposure. To determine whether internal carotid artery flow velocity increased with exercise in long-term residents of high altitude and whether resting values and the response to exercise differed in lifelong vs. acclimatized newcomer male residents of high altitude, we studied 15 native Tibetan and 11 Han ("Chinese") 6 +/- 2-yr residents of Lhasa (3,658 m), Tibet Autonomous Region, China. Noninvasive Doppler ultrasound was used to measure internal carotid artery diameter, mean flow velocity, and, in combination, hemoglobin and arterial O2 saturation to assess cerebral O2 delivery. Tibetan and Han groups were similar in body size and resting internal carotid artery diameter, blood pressure, hemoglobin concentration, internal carotid artery mean flow velocity, and calculated cerebral O2 delivery. Submaximal exercise increased internal carotid artery mean flow velocity and cerebral O2 delivery in the Tibetan and Han subjects. At peak exercise, the Tibetans sustained the increase in flow velocity and cerebral O2 delivery, whereas the Hans did not. Across all exercise levels up to and including peak effort, the Tibetans demonstrated a greater increase in internal carotid artery flow velocity and cerebral O2 delivery relative to resting values than did the Hans. The greater cerebral O2 delivery was accompanied by increased peak exercise capacity in the Tibetan compared with the Han group. Our findings suggest that the cerebral blood flow response to exercise is maintained in Tibetan lifelong residents of high altitude.

The deleterious effects of intraoperative hypotension on outcome in patients with severe head injuries

Prehospital or admission hypotension doubles the mortality for patients with severe head injury (SHI = Glasgow Coma Scale score less than or equal to 8). To our knowledge no study to date has determined the effects of intraoperative hypotension [IH: systolic blood pressure (SBP) less than 90 mm Hg] on outcome in patients with SHI. This study examined 53 patients who had SHI and required early surgical intervention (surgery within 72 hours of injury). All patients were initially normotensive on arrival. There were 17 patients (32%) who developed IH and 36 (68%) who remained normotensive throughout surgery. The mortality rate was 82% in the IH group and 25% in the normotensive group (p less than 0.001). The duration of IH was inversely correlated with Glasgow Outcome Scale using linear regression (R = -0.30; p = 0.02). Despite vigorous fluid resuscitation in the IH group, additional pharmacologic support was used in only 32%. These data suggest that IH is not uncommon after SHI (32%) and that it does have a significant effect on patient outcome.

[The use of 6-flavor Rehmannia decoction with additives in the prevention of ototoxic deafness induced by gentamicin in guinea pigs]

The purpose of this study is to discuss the effects of the Chinese medicine six-flavor Rehmannia Decoction with additives on preventing deafness induced by gentamicin (GM) in guinea pig by means of testing the thresholds of Preyer's reflex (PR) cochlear microphonic potential (CM), action potential of the auditory nerve (N1) and scanning electron microscope of inner ear (SEM). The results showed that the medicine is effective in reducing the ototoxic effect of GM on inner ear.

Focal brain injury results in severe cerebral ischemia despite maintenance of cerebral perfusion pressure

Severe head injury often causes an increase in intracranial pressure (ICP) and decreases in cerebral blood flow (CBF) and cerebral oxygen delivery (CO2del). To determine if this reduction in CBF and CO2del would produce cerebral ischemia and if this reduction would be abrogated by maintaining global cerebral perfusion pressure (CPP), we studied CPP, ICP, CBF, CO2del, cerebral oxygen extraction ratio (CO2ER), and cortical water content (CWC) in a porcine model of focal cryogenic brain injury. Fifteen mature swine were randomized to two groups. The experimental group (n = 7) had a brain lesion and was studied for 24 hours. The control group (n = 8) was instrumented only. Cryogenic injury significantly increased ICP and decreased CBF and CO2del compared with controls. There were no significant differences in CPP between the groups for the entire experiment, and the CPP was well above the ischemic threshold. The CO2ER significantly increased in the first three hours after brain injury. However, CO2ER in experimental animals tended to decrease 12 hours after brain injury and was not significantly different from that in controls. Cryogenic injury significantly increased the CWC in the lesioned hemisphere. These data indicate that focal brain injury results in persistent ischemia despite the normalization of CPP, suggesting that a significant increase in cerebral vascular resistance (CVR) occurs after brain injury. We conclude that in addition to maintenance of CPP, intervention to reduce CVR may be important in the management of brain injury.

Hemorrhagic hypotension after brain injury causes an early and sustained reduction in cerebral oxygen delivery despite normalization of systemic oxygen delivery

Morbidity and mortality are doubled when hemorrhagic hypotension (HEM) accompanies a traumatic brain injury (TBI). Hemorrhagic hypotension initiates a "secondary" injury (SI) that has been attributed to ischemia, but this has not been confirmed in the laboratory. All previous studies have been of relatively short duration (less than 6 hours), allowing insufficient time to study the pathophysiology of SI, since maximal intracranial pressure (ICP) elevations may occur 16 to 20 hours after injury. We hypothesized that HEM combined with TBI would reduce cerebral oxygen delivery (cO2del) and cerebral metabolic rate for oxygen (cMRO2) to a greater degree than would occur with TBI alone. In a porcine model of TBI and HEM we recorded systemic oxygen delivery (sO2del), ICP, cerebral blood flow (CBF), cO2del, cMRO2, brain oxygen extraction ratio (cO2ER), and cortical water content (CWC) over a 24-hour study period. Controls (n = 7) were instrumented only, group 1 (n = 14) received a focal cryogenic lesion only, group 2 (n = 21) received a cryogenic lesion plus hemorrhage to 50 mm Hg for 45 minutes. Animals were resuscitated with crystalloid solutions; shed blood in group 2 animals was returned after one hour. Hemorrhagic hypotension following TBI produced a significant and sustained reduction in cO2del associated with a lower cMRO2 and cO2ER, and higher ICP and CWC, than seen with lesion alone. This occurred despite adequate early restoration of sO2del. This confirms that cerebral ischemia is ongoing despite restoration of systemic hemodynamics.

Intravenous fluid tonicity: effect on intracranial pressure, cerebral blood flow, and cerebral oxygen delivery in focal brain injury

An investigation into the role of intravenous fluid tonicity in determining intracranial pressure (ICP) after brain injury is described. The authors compare the results of infusion of a hypotonic fluid (Ringer's lactate, 270 mOsm/liter) to those of a hypertonic fluid (hypertonic sodium lactate, 500 mOsm/liter) in a porcine model of focal cryogenic brain injury. Hemodynamic parameters (ICP, regional cerebral blood flow (CBF), and oxygen delivery) and serum osmolarity were measured every 3 hours for 24 hours after injury. At sacrifice, the water content of the lesioned and nonlesioned cortex was determined by specific gravity. The cryogenic injury produced a significant increase in ICP and a significant decrease in CBF in all experimental groups. Maintenance infusion of hypertonic sodium lactate for 24 hours resulted in significantly lower ICP, higher CBF and oxygen delivery, and higher serum osmolarity than Ringer's lactate infusion. Cortical water content in the area of the lesion was similar in both groups, but in the uninjured hemisphere it was significantly lower in the hypertonic group. These data suggest that hypertonic maintenance fluid improves intracranial compliance by dehydrating uninjured cortex. Improved CBF in the hypertonic group may be due to dehydration of cerebrovascular endothelium and erythrocytes. By reducing ICP and improving CBF, hypertonic fluid administration may thus reduce secondary brain injury after head trauma.

Hypertonic fluid resuscitation improves cerebral oxygen delivery and reduces intracranial pressure after hemorrhagic shock

Prospective clinical studies have shown that hypotension from hemorrhage contributes to increased morbidity and mortality in patients with traumatic brain injury. It is implied that poorer outcome is the result of secondary brain injury from impaired cerebral oxygen delivery (cO2del). We studied the early and late effects of hypertonic sodium lactate (HSL: 500 mOsm/L) resuscitation on mean arterial pressure (MAP), cardiac output (CO), systemic oxygen delivery (sO2del), cerebral perfusion pressure (CPP), intracranial pressure (ICP), cO2del, cerebral blood flow (CBF), serum osmolality, and cortical water content (CWC) in a porcine model of hemorrhagic shock. Swine were randomized to receive a bolus (4 mL/kg) of either lactated Ringer's solution (LR: 274 mOsm/L) or HSL after shock, followed by either LR or HSL to return MAP to baseline levels. Shed blood was returned 1 hour after resuscitation, and all animals were studied for 24 hours. Control animals were instrumented only. The HSL resuscitation significantly increased cO2del and CBF for 24 hours postresuscitation when compared with LR. The ICP in the HSL-treated animals was significantly lower throughout the postresuscitation phase when compared with the LR-treated animals (p less than 0.05). The CWC was significantly lower in the HSL-treated animals (p less than 0.05). We attribute these effects to hypertonic dehydration of both the brain parenchyma and the cerebrovascular endothelium. These data suggest that by decreasing ICP and improving cO2del after shock, HSL could decrease secondary brain injury when brain injury and shock occur together.

PvuII polymorphism at the COL1A2 locus

Images