Nutritional deprivation of alpha-linolenic acid decreases but does not abolish turnover and availability of unacylated docosahexaenoic acid and docosahexaenoyl-CoA in rat brain

We applied our in vivo fatty acid method to examine concentrations, incorporation, and turnover rates of docosahexaenoic acid (22:6 n-3) in brains of rats subject to a dietary deficiency of alpha-linolenic acid (18:3 n-3) for three generations. Adult deficient and adequate rats of the F3 generation were infused intravenously with [4, 5-(3)H]docosahexaenoic acid over 5 min, after which brain uptake and distribution of tracer were measured. Before infusion, the plasma 22:6 n-3 level was 0.2 nmol ml(-1) in 18:3 n-3-deficient compared with 10.6 nmol ml(-1) in control rats. Brain unesterified 22:6 n-3 was not detectable, whereas docosahexaenoyl-CoA content was reduced by 95%, and 22:6 n-3 content in different phospholipid classes was reduced by 83-88% in deficient rats. Neither plasma or brain arachidonic acid (20:4 n-6) level was significantly changed with diet. Docosapentaenoic acid (22:5 n-6) reciprocally replaced 22:6 n-3 in brain phospholipids. Calculations using operational equations from our model indicated that 22:6 n-3 incorporation from plasma into brain was reduced 40-fold by 18:3 n-3 deficiency. Recycling of 22:6 n-3 due to deacylation-reacylation within phospholipids was reduced by 30-70% with the deficient diet, but animals nevertheless continued to produce 22:6 n-3 and docosahexaenoyl-CoA for brain function. We propose that functional brain effects of n-3 deficiency reflect altered ratios of n-6 to n-3 fatty acids.

Effects of empiric antibiotic administration for suspected pneumonia on subsequent opportunistic pulmonary infections

Optimal guidelines for empiric antibiotic (EAB) therapy in cases of suspected post-traumatic ventilator-associated pneumonia (VAP) are not well defined. EAB administration is thought to increase the incidence of opportunistic organisms; however, culture-directed (as opposed to empiric) treatment may delay antibiotic administration with possible adverse consequences. Our goal was to examine the impact of EAB administration on the incidence of subsequent VAP and opportunistic organisms in a series of critically injured patients with sepsis syndrome. This is a retrospective review of all patients admitted to a Level I trauma center who underwent multiple fiberoptic bronchoscopies (FOBs) for diagnosis of suspected VAP as the cause of postinjury sepsis syndrome. The relationships between EAB administration, positive cultures (>10(5) colony-forming units) at repeat FOB, and prevalence of opportunistic organisms (methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Stenotrophomonas species, Acinetobacter species, and/or yeast) were evaluated. Over a 13-month period ending on January 1, 1999, 36 intubated trauma patients underwent more than one FOB during their intensive care unit stay. Twenty-nine patients received EAB immediately after the initial FOB. There was no difference in the rate of EAB administration in patients who developed subsequent VAP after initial FOB (19 of 24, 79%) versus those who did not develop VAP (10 of 12, 83%; P = 0.65). There were 30 VAPs diagnosed in 58 subsequent FOBs (i.e., after the initial FOB) of which 23 were due to an opportunistic organism compared with two VAPs due to an opportunistic organism diagnosed at initial FOB (P < 0.001). Twenty-one of the 23 opportunistic VAPs at subsequent FOBs had received EAB before the first FOB compared with four of seven nonopportunistic organisms (P = 0.06). Administration of EAB does not impact the incidence of subsequent VAP. However, EAB may be related to the development of subsequent opportunistic pulmonary infections.

Predictors of survival among elders suffering strokes in Taiwan: observation from a nationally representative sample

BACKGROUND AND PURPOSE

Cerebrovascular disease was the leading cause of death in Taiwan from 1963 to 1982. Deaths due to stroke now rank second only to cancer, with more deaths resulting from strokes than from any other single pathology. It is important to understand stroke prognosis among elderly stroke survivors, with respect to survival and attendant predictive factors, because aged population in Taiwan is growing rapidly. The aim of the present study was to discern factors affecting survival in stroke patients from a nationally representative elderly sample.

METHODS

A total of 99 stroke survivors, from a representative national sample of elders aged >/=65 years on December 31, 1988, whose strokes occurred in the period 1989-1993, were followed for mortality until July 1, 1995. Personal data were gathered through home interviews conducted by well-trained community nurses, and mortality data were obtained from the national census office by using identification card numbers. Cox proportional hazards regression analysis and the stepwise technique were used to search for important prognostic factors of survival.

RESULTS

Women experienced a higher mortality rate (139.8 per 1000 person-years) than men (126.4 per 1000 person-years), as age-adjusted for World Health Organization world-population figures. Stroke patients who received continuous treatment for diabetes experienced mortality risks similar to those of patients without diabetes and much lower risks than those with discontinuous diabetes treatment. Cognitive impairment was also an independent predictor of survival (relative risk 2.69, P<0.05). In addition, patients with both cognitive and mobility impairments had a 2- to 3-fold greater risk of mortality than those with only a single abnormality.

CONCLUSIONS

This first report on the various prognostic factors related to survival of elderly stroke patients in Taiwan's Chinese population emphasized the benefit of continuous diabetes treatment in improving survival chances. These stroke patients should also be monitored for cognitive and mobility impairments and undergo rehabilitation.

Effects of surfactants on extraction of phenanthrene in spiked sand

Problems associated with polynuclear aromatic hydrocarbon (PAH) contaminated site in environmental media have received increasing attention. To resolve such problems, innovative in situ methods are urgently required. This work investigated the feasibility of using surfactants to extract phenanthrene on spiked sand in a batch system. Phenanthrene was spiked into Ottawa sand to simulate contaminated soil. Six surfactants, Brij 30 (BR), Triton X-100 (TR), Tergitol NP-10 (TE), Igepal CA-720 (IG), sodium dodecyl sulfate (SDS) and hexadecyl trimethyl ammonium bromide (HTAB) were used. Adjusting the extraction time, mixing speed and surfactant concentration yielded the optimum extracting conditions. The concentration of phenanthrene was identified with HPLC. Under the experimental conditions, results indicated that those surfactants were highly promising on site remediation since the residual phenanthrene concentration was effectively reduced. The optimum operating conditions were obtained at 30 min, 125 rpm and surfactant concentrations in 4%.

Surgical treatment for peroneal nerve palsy

BACKGROUND

Peroneal nerve palsy is the most frequently encountered mononeuropathy of the lower extremities. Although many studies advocated spontaneous resolution of peroneal nerve palsy, more recent studies confirmed obvious improvement with surgical treatment techniques.

METHODS

This study reviewed the results obtained from surgically treated peroneal nerve palsy in 14 patients who were admitted to our hospital between 1990 and 1996. The patients consisted of 12 males and two females with an average age of 31 years (range, 12-68 years). Peroneal nerve palsy in these patients was caused by direct or indirect injury, as confirmed by clinical examination and electromyography. The status of the nerve was observed for at least 4 months and explored when the nerve failed to reveal evidence of recovery. The nerve was decompressed, repaired or reconstructed by nerve grafting, according to the status of the injury. Weber scales were used to assess the peripheral neuropathies preoperatively and postoperatively.

RESULTS

At a mean of 23 months (range, 11-61 months), nerve palsy scores improved from an average of 5 points to 3.14 points. Despite the small number of patients, our results indicated that the time interval between onset of injury and date of surgical treatment (p < 0.05) was the most significant factor to influence the prognosis of surgery. Results obtained from surgery were not related to the method of treatment, length of nerve graft or mechanism of injury.

CONCLUSIONS

Because peroneal nerve palsy does not always resolve spontaneously, this study favored early surgical exploration for peroneal nerve dysfunction, based on at least 4 months of follow-up.

Areca nut extract up-regulates prostaglandin production, cyclooxygenase-2 mRNA and protein expression of human oral keratinocytes

There are about 600 million betel quid (BQ) chewers in the world. BQ chewing is associated with increased incidence of oral cancer and submucous fibrosis. In this study, areca nut (AN) extract (200-800 microg/ml) induced the prostaglandin E(2) (PGE(2)) production by 1. 4-3.4-fold and 6-keto-PGF(1 alpha) production by 1.1-1.7-fold of gingival keratinocytes (GK), respectively, following 24 h of exposure. Exposure of GK to AN extract (>400 microg/ml) led to cell retraction and intracellular vacuoles formation. At concentrations of 800 and 1200 microg/ml, AN extract induced cell death at 21-24 and 32-52% as detected by MTT assay and cellular lactate dehydrogenase release, respectively. Interestingly, AN-induced morphological changes of GK are reversible. GK can still proliferate following exposure to AN extract. Cytotoxicity of AN extract cannot be inhibited by indomethacin (1 microM) and aspirin (50 microM), indicating that prostaglandin (PG) production is not the major factor responsible for AN cytotoxicity. PGE(2) exhibited little effect on the growth of GK at concentrations ranging from 100-1000 pg/ml. Stimulating GK production of PGs by AN extract could be due to induction of cyclooxygenase-2 (COX-2) mRNA expression and protein production. These results suggest that AN ingredients are critical in the pathogenesis of oral submucous fibrosis and oral cancer via their stimulatory effects on the PGs, COX-2 production and associated tissue inflammatory responses. AN cytotoxicity to GK is not directly mediated by COX-2 stimulation and PG production.

Maintaining survivors' values of left ventricular power output during shock resuscitation: a prospective pilot study

OBJECTIVE

Maintaining left ventricular power output (LVP) > 320 mm Hg x L/min/m2 during resuscitation has been retrospectively associated with faster resolution of acidosis and survival after posttraumatic shock. The purpose of this prospective study was to evaluate the effects of maintaining LVP above this threshold during resuscitation on base deficit clearance, organ failure, and survival.

METHODS

This was a study of a consecutive series of critically injured patients (PWR) monitored with a pulmonary artery catheter during initial resuscitation. LVP, calculated as cardiac index-(mean arterial pressure-central venous pressure), was maintained >320 mm Hg x L/min/m2 via a predefined protocol by using ventricular pressure-volume diagrams. Outcome was assessed by base deficit clearance (<6 mEq/L) in <24 hours, lowest base deficit in the first 24 hours after admission (24-hr base deficit), organ dysfunctions/patient, and survival. Results were compared with 39 control patients (OXY) with identical enrollment criteria from a previous prospective study who were resuscitated based on oxygen transport criteria.

RESULTS

Twenty patients were studied over a 6-month period. Mean LVP during resuscitation in the PWR group was 360 +/- 100 mm Hg x L/min/m2. Admission base deficit was similar between the two groups (PWR 11 +/- 4.2 vs. OXY 11 +/- 5.8 mEq/L;p = 0.66). More PWR patients cleared base deficit in < 24 hours than OXY patients (16 of 20 vs. 17 of 39, p = 0.009, Fisher's exact test), and the PWR patients had a significantly lower 24-hr base deficit (3.9 +/- 3.7 vs. 7.1 +/- 4.6 mEq/L, p = 0.01). Organ dysfunction rate was lower in the PWR group (2.1 +/- 1.5 vs. 3.2 +/- 1.4 organ dysfunctions/patient, p = 0.007). Survival in the PWR group was 15 of 20, versus 21 of 39 in the OXY group (p = 0.10).

CONCLUSION

Prospectively maintaining LVP above 320 mm Hg x L/min/m2 during resuscitation is an achievable goal. It is associated with improved base deficit clearance and a lower rate of organ dysfunction after resuscitation from traumatic shock.

Epstein-Barr virus-associated gastric carcinomas: relation to H. pylori infection and genetic alterations

BACKGROUND & AIMS

The association of Epstein-Barr virus (EBV) and gastric carcinomas (GCs) has been shown to vary among different populations and certain histological subtypes. Few studies have addressed the status of Helicobacter pylori infection and genetic alterations in these EBV-positive or -negative GCs.

METHODS

Eleven gastric lymphoepithelioma-like carcinomas (LELCs) and 139 cases of common non-LELCs were evaluated for the presence of EBV DNA using polymerase chain reaction (PCR) and RNA in situ hybridization. H. pylori infection was determined by anti-H. pylori immunoglobulin G in preoperative sera. Immunostaining for p53, c-erbB-2, and E-cadherin was performed. Microsatellite instability was analyzed by PCR using 10 primers.

RESULTS

EBV was detected in 11 (100%) LELCs and in 19 (13.7%) of 139 common GCs. Compared with EBV-negative GCs, gastric LELCs tended to have a relatively higher frequency of proximal location, diffuse histological subtype, p53 overexpression, and reduced E-cadherin expression but a lower frequency of lymph node metastasis, previous H. pylori infection, and c-erbB-2 overexpression. In contrast, no significant difference of clinicopathologic and genetic profiles was observed between EBV-positive non-LELC GCs and EBV-negative GCs. No correlation of microsatellite instability was found among these 3 subsets of GCs.

CONCLUSIONS

Dissecting clinicopathologic characteristics and infection status of EBV and H. pylori provide additional evidence of etiological and genetic heterogeneity for GC. Distinct clinicopathologic and genetic pathways exist in gastric LELCs, in which EBV may play a more important role than H. pylori infection.

Distinct clinicopathologic and genetic profiles in sporadic gastric cancer with different mutator phenotypes

A subset of sporadic gastric cancers (GC) exhibits microsatellite instability (MSI). To define the precise role of MSI in GC, a total of 100 patients with sporadic GC were classified into three groups, i.e., high-frequency MSI (MSI-H), low-frequency MSI (MSI-L), and microsatellite stable (MSS), based on 10 microsatellite markers. Mutational analyses of TGFbetaRII, IGFIIR, BAX, MSH3, MSH6, E2F4, MSH2, MLH1, and TP53 genes, and methylation and protein expression of MLH1 and MSH2 were performed and correlated. Twenty-seven percent of GC showed MSI at least in one locus and could be further graded as MSI-H (14%) and MSI-L (13%). No clinicopathologic difference was noted between GC with MSI-L and MSS. Compared with GC with MSI-L or MSS, GC with MSI-H had a significantly higher frequency of antral location, intestinal subtype, H. pylori seropositivity, but a lower incidence of lymph node metastasis, and displayed a higher frequency of frameshift mutations of TGFbetaRII, IGFIIR, BAX, MSH3, and E2F4 genes but a lower incidence of TP53 mutations. Furthermore, hypermethylation of the MLH1 promoter was responsible for the loss of protein function in 13 of 14 MSI-H tumors. It was concluded that a specific phenotype and a distinct profile of genetic alterations exist in MSI-H GC. We speculate that epigenetic inactivation of MLH1 by methylation plays a crucial role in initiating such a pathway of carcinogenesis. In contrast, GCs with MSS and MSI-L exhibit clinicopathologic features that are distinct from MSI-H tumors and have a higher frequency of TP53 mutations, suggesting that they may evolve through an entirely different pathway.

Distinct clinicopathologic and genetic profiles in sporadic gastric cancer with different mutator phenotypes

A subset of sporadic gastric cancers (GC) exhibits microsatellite instability (MSI). To define the precise role of MSI in GC, a total of 100 patients with sporadic GC were classified into three groups, i.e., high-frequency MSI (MSI-H), low-frequency MSI (MSI-L), and microsatellite stable (MSS), based on 10 microsatellite markers. Mutational analyses of TGFbetaRII, IGFIIR, BAX, MSH3, MSH6, E2F4, MSH2, MLH1, and TP53 genes, and methylation and protein expression of MLH1 and MSH2 were performed and correlated. Twenty-seven percent of GC showed MSI at least in one locus and could be further graded as MSI-H (14%) and MSI-L (13%). No clinicopathologic difference was noted between GC with MSI-L and MSS. Compared with GC with MSI-L or MSS, GC with MSI-H had a significantly higher frequency of antral location, intestinal subtype, H. pylori seropositivity, but a lower incidence of lymph node metastasis, and displayed a higher frequency of frameshift mutations of TGFbetaRII, IGFIIR, BAX, MSH3, and E2F4 genes but a lower incidence of TP53 mutations. Furthermore, hypermethylation of the MLH1 promoter was responsible for the loss of protein function in 13 of 14 MSI-H tumors. It was concluded that a specific phenotype and a distinct profile of genetic alterations exist in MSI-H GC. We speculate that epigenetic inactivation of MLH1 by methylation plays a crucial role in initiating such a pathway of carcinogenesis. In contrast, GCs with MSS and MSI-L exhibit clinicopathologic features that are distinct from MSI-H tumors and have a higher frequency of TP53 mutations, suggesting that they may evolve through an entirely different pathway.

Effect of exercise on blood pressure in pregnant women with a high risk of gestational hypertensive disorders

OBJECTIVE

To prospectively determine whether moderate exercise during pregnancy lowers blood pressure.

STUDY DESIGN

A randomized, controlled trial with one test group and one control group. All subjects have a history of mild hypertension, gestational hypertensive disorders or a family history of hypertensive disorders. Subjects were recruited before 14 weeks' gestation. After four weeks of observation, the subjects were randomly assigned to either the exercise or control group. The exercise group visited the laboratory three times a week for 10 weeks (18-28 gestation weeks) to perform 30 minutes of exercise at Rating of Perceived Exertion level 13.

RESULTS

A total of 16 pregnant women (mean age, 30 years) participated. The mean metabolic equivalent during exercise sessions was 4.7 (SD = 0.8). Blood pressure measurements were compared before and after the 10-week exercise period in the two groups. Systolic blood pressures did not change significantly, but diastolic blood pressure (DBP) in the exercise group decreased by 3.5 mm Hg, while that in the control group increased by 1.1 mm Hg. Thus, the pre-post change in DBP differed by 4.6 mm Hg between groups. Exercise treatment reduced the diastolic blood pressure to a near-significant level in the exercise group (t = 2.34, df = 7, P = .052). Percent body fat did not differ between the exercise and control groups either before or after exercise treatment. ANOVA revealed that pregnancy had a significant effect (F(1, 14) = 5.7, P = .03) on increasing the percentage of fat, but exercise treatment did not (F(1, 14) = .18, P = .68). Estimated energy expenditure in overall daily physical activities during the intervention did not differ between the two groups despite the inclusion of exercise.

CONCLUSION

This study detected a strong trend that 10 weeks of moderate exercise lowered the diastolic blood pressure among pregnant women at risk of hypertensive disorders. The reductions were probably due to the effect of exercise itself, not to weight or overall daily physical activity levels.

85 kDa cytosolic phospholipase A2 is a target for chronic lithium in rat brain

The mechanism by which chronic lithium exerts its therapeutic effect in brains of bipolar patients is not known. One possibility, suggested by our demonstration in the rat brain, is that chronic lithium inhibits turnover of arachidonic acid (AA) by reducing the activity of an AA-specific phospholipase A2 (PLA2). To test this further, mRNA levels of two AA-specific PLA2s, cytosolic PLA2 (cPLA2) type IV and intracellular PLA2 (iPLA2) type VIII, and protein level of cPLA2 were quantified in the brain of rats given lithium for 6 weeks. Chronic lithium markedly reduced brain mRNA and protein level of cPLA2, but had no effect on mRNA level of iPLA2. These results suggest that the final common path effect of chronic lithium administration is to reduce turnover of AA in brain by down-regulating cPLA2.

Effects of Butyrate and Propionate on the Adhesion, Growth, Cell Cycle Kinetics, and Protein Synthesis of Cultured Human Gingival Fibroblasts

BACKGROUND

Various periodontal and root canal pathogens, such as the Bacteroides species, can produce significant amounts of short chain fatty acids (SCFA). The roles of SCFA in the pathogenesis of periodontal disease are still not fully understood.

METHODS

We therefore investigated 2 main SCFA, butyrate and propionate, on the functional behavior of cultured human gingival fibroblasts (GF) such as cell growth, protein synthesis, cell adhesion capacity, and cell cycle progression.

RESULTS

Butyrate and propionate inhibited the growth of healthy (HGF) and inflamed gingival fibroblasts (IGF) in a dose dependent manner. At concentrations of 4, 8, and 16 mM, butyrate suppressed the cell growth by 11 to 58%, 16 to 60%, and 50 to 71%, respectively. The response of cultured gingival fibroblasts to SCFA showed individual differences. Morphologically, GF became larger and more flattened in appearance following exposure to butyrate (>8 mM) and propionate (>24 mM) for 5 days. Inhibitory effects of butyrate (>2 mM) and propionate (>8 mM) on the growth of GF were due possibly to their inhibition of cell-cycle progression. At concentrations of 2 and 8 mM, butyrate led to G0/G1 arrest. Elevation of the exposure concentration to 8 to 24 mM further result in G2/M phase arrest of GF. On the other hand, propionate, at concentrations ranging from 4 to 24 mM, led to G0/G1 arrest. Butyrate (>2 mM) inhibited the proline-rich protein synthesis of GF. At concentrations of 4, 8, 16, and 24 mM, butyrate inhibited the protein synthesis of HGF-1 by 42%, 43%, 51%, and 54%, respectively. In all strains of cultured GF, the suppressive effect of propionate is less than that of butyrate. At concentration range of 4 to 24 mM, propionate suppressed the protein synthesis of HGF-1 by 23 to 43%. However, both butyrate and propionate (4 to 48 mM) exerted little effects on the adhesion of GF to type I collagen within 3 hours of incubation.

CONCLUSIONS

These results suggested that SCFA released by pathogenic microorganisms can contribute to the gingival tissue dysfunction and breakdown through their actions on specific biological functions of GF.

Systemic inflammatory response syndrome in the trauma intensive care unit: who is infected?

BACKGROUND

Systemic inflammatory response syndrome (SIRS) is common in trauma patients, and infection represents an important and treatable source of SIRS. C-Reactive protein (CRP), an acute phase protein, is elevated in infection and discriminates between infected and uninfected patients in other patient populations. Our goal was to examine the ability of CRP and other commonly used markers of infection (maximum temperature [Tmax], and white blood cell count [WBC]) to distinguish between infectious and noninfectious causes of SIRS.

METHODS

This was a prospective study of a consecutive series of trauma patients who spent greater than 48 hours in the intensive care unit. Studied variables included CRP, Tmax, WBC, and culture-proven infection compared with standard definitions of infection and the presence of SIRS. The ability of these variables to correctly classify patients as infected (INF) or not infected was examined by using receiver operating characteristic curves. Values on the day of infection diagnosis in the INF group and on postadmission day 5 (the mean day of onset of infection in the INF group) in the not infected group were used. Multivariate discriminant analysis was used to examine the relative contributions of Tmax and CRP in predicting infection. Significance was defined as p < 0.05.

RESULTS

Fifty-nine patients were admitted over a 4-month period. Of these, 35 patients (59%) had SIRS at the time of comparison (29 INF, 6 not infected). Thirty-three patients (56%) developed an infection. Both CRP and Tmax discriminated between patients with and without infection whereas WBC did not (areas under receiver operating characteristic curve: 0.86, 0.81, and 0.47, respectively). In patients with SIRS, cutoff values of 17 mg/dL for CRP (specificity 100%) and 102 degrees F for Tmax (specificity 83%) were identified. CRP added significant discriminatory power to Tmax in determining presence of infection in patients with SIRS (p = 0.003).

CONCLUSION

Infection must be presumed to be the source of SIRS in patients with CRP more than 17 mg/dL and Tmax more than 102 degrees F after postinjury day 4. WBC is not useful in determining the presence of infection.

Ligament reconstruction and tendon interpositional arthroplasty for degenerative arthritis of the thumb trapeziometacarpal joint

BACKGROUND

The trapeziometacarpal joint provides important functions for the hand. This joint is often involved in primary osteoarthritis.

METHODS

From November 1982 to December 1995, we encountered 42 patients (47 hands) with osteoarthritis (OA). All the patients were Chinese. Thirty-six patients (36 hands) were treated surgically. Ligament reconstruction and tendon interposition arthroplasty were done with total removal of the trapezium or partial removal of trapeziometacarpal joint depending on the stage of the disease. These patients were monitored for an average of 106 months and evaluated both clinically and roentgenographically.

RESULTS

Of three stage II cases, the results of two were excellent and one was good. Of the 18 stage III patients, 14 had excellent (77.8%) and four had good (22.2%) results. In the 15 stage IV patients, 10 had excellent (66.6%), four had good (26.7%) and one had fair (6.7%) results. No patient had poor results.

CONCLUSIONS

Ligament reconstruction and tendon interpositional arthroplasty is a good alternative in treating degenerative arthritis of the trapeziometacarpal joint of the thumb. Partial removal of the diseased joint is indicated for stage II, and total removal of the trapezium is indicated for stage III and IV patients. Men seek treatment more often than women due to their need to work, even though women are more commonly afflicted with this disorder.

Stress, social relations, and old age mortality in Taiwan

The research analyzed the relationships among stress, social relations, and mortality in a probability sample of 4,049 Taiwanese adults, aged 60 and over. The baseline survey was conducted in 1989 and the survival status of the respondents was ascertained during the subsequent 4 years. Death of a spouse or a child was found to increase the risk of dying directly and indirectly, whereas major financial difficulty during the past 5 years and current financial strain influenced mortality indirectly through their effects on self-rated health disability. In addition to their direct effect on mortality, martial status and work status lowered the probability of dying through decreased disability and subjective ill health. Finally, no buffering effects of social support were substantiated.

Interleukin-6 inhibits transforming growth factor-beta-induced apoptosis through the phosphatidylinositol 3-kinase/Akt and signal transducers and activators of transcription 3 pathways

The multifunctional cytokine interleukin-6 (IL-6) regulates growth and differentiation of many cell types and induces production of acute-phase proteins in hepatocytes. Here we report that IL-6 protects hepatoma cells from apoptosis induced by transforming growth factor-beta (TGF-beta), a well known apoptotic inducer in liver cells. Addition of IL-6 blocked TGF-beta-induced activation of caspase-3 while showing no effect on the induction of plasminogen activator inhibitor-1 and p15(INK4B) genes, indicating that IL-6 interferes with only a subset of TGF-beta activities. To further elucidate the mechanism of this anti-apoptotic effect of IL-6, we investigated which signaling pathway transduced by IL-6 is responsible for this effect. IL-6 stimulation of hepatoma cells induced a rapid tyrosine phosphorylation of the p85 subunit of phosphatidylinositol 3-kinase (PI 3-kinase) and its kinase activity followed by the activation of Akt. Inhibition of PI 3-kinase by wortmannin or LY294002 abolished the protection of IL-6 against TGF-beta-induced apoptosis. A dominant-negative Akt also abrogated this anti-apoptotic effect. Dominant-negative inhibition of STAT3, however, only weakly attenuated the IL-6-induced protection. Finally, inhibition of both STAT3 and PI 3-kinase by treating cells overexpressing the dominant-negative STAT3 with LY294002 completely blocked IL-6-induced survival signal. Thus, concomitant activation of the PI 3-kinase/Akt and the STAT3 pathways mediates the anti-apoptotic effect of IL-6 against TGF-beta, with the former likely playing a major role in this anti-apoptosis.

Treatment of large skeletal defects in the lower extremities using double-strut, free vascularized fibular bone grafting

This article reports on the use of double-strut, free vascularized fibular grafts to treat six patients with infected nonunion or traumatic bone loss in the femur or tibia after prolonged treatment and multiple operations. The defects were 6-13 cm long. Five patients achieved solid union within 6 months, and one patient required additional cancellous grafting to achieve union at the distal end of the fibula. One patient experienced a stress fracture due to strenuous exercise, and union was achieved 3 months after reapplying an external fixator. Although three patients had some restricted knee motion, all patients had a satisfactory outcome in regard to walking, and no limb-length discrepancies were noted in any patient.

Reduced palmitate turnover in brain phospholipids of pentobarbital-anesthetized rats

Our laboratory has reported that pentobarbital-induced anesthesia reduced the incorporation of intravenously injected radiolabeled palmitic acid into brain phospholipids. To determine if this decrease reflected a pentobarbital-induced decrease in palmitate turnover in phospholipids, we applied our method and model to study net flux and turnover of palmitate in brain phospholipids (1). Awake, light and deep pentobarbital (25-70 mg/kg, iv) anesthetized rats were infused with [9,10-3H]palmitate over a 5 min period. Brain electrical activity was monitored by electroencephalography. An isoelectric electroencephalogram characterized deep pentobarbital anesthesia. Net incorporation rates (J(FA,i)) and turnover rates (Fi) of palmitate were calculated. J(FA,i) for palmitate incorporated into phospholipids was dramatically reduced by pentobarbital treatment in a dose-dependent manner, by 70% and 90% respectively for lightly and deeply anesthetized animals, compared with awake controls. Turnover rates for palmitate in total phospholipid and individual phospholipid classes were decreased by nearly 70% and 90% for lightly and deeply anesthetized animals, respectively. Thus, pentobarbital decreases, in a dose-dependent manner, the turnover of palmitate in brain phospholipids. This suggests that palmitate turnover is closely coupled to brain functional activity.

The effects of extracellular citric acid acidosis on the viability, cellular adhesion capacity and protein synthesis of cultured human gingival fibroblasts

Root surface demineralization is widely used as an adjunct to periodontal treatment. To clarify the influence of citric acid root conditioning on periodontal wound healing, the effects of citric acid and associated extracellular acidosis on the viability (MTT assay), attachment and protein synthesis ([3H]-proline incorporation into trichloroacetic acid-precipitated proteins) of human gingival fibroblasts (GF) were investigated. A concentration of 47.6 mmol/L of citric acid (pH 2.3) in water led to total cell death within three minutes of incubation. Media containing 23.8 mmol/L and 47.6 mmol/L of citric acid exerted strong cytotoxicity (47 to 90 per cent of cell death) and inhibited protein synthesis (IC50 = 0.28 per cent) of GF within three hours of incubation. Incubation of cells in a medium containing 11.9 mmol/L of citric acid also suppressed the attachment and spreading of fibroblasts on culture plates and Type I collagen, with 58 per cent and 22 per cent of inhibition, respectively. Culture medium supplemented with 11.9, 23.8 and 47.6 mmol/L of citric acid also led to extracellular acidosis by decreasing the pH value from 7.5 to 6.3, 5.2 and 3.8, respectively. In addition, it was confirmed that the toxic effect of media containing citric acid was due to their acidity rather than the citrate content. Most of the citric acid-induced cell death could be prevented by adjusting the pH value of the culture medium to pH 7.5. Sodium citrate, at a concentration of 47.6 mmol/L, also exerted little cytotoxicity. The results suggested that toxicity of citric acid in specific stages of the healing process must be considered prior to its clinical application. Careful management of citric acid in order to avoid contact with tissue or the development of other demineralizing agents is important in enhancing periodontal wound healing.

"Blind" placement of long-term central venous access devices: report of 589 consecutive procedures

Placement of long-term central venous access devices, such as Hickman catheters and implanted subcutaneous ports, has traditionally been performed in the operating room with fluoroscopy. This study reports our experience with percutaneous placement of these devices in the outpatient clinic setting without the use of real-time imaging. Results were generated from a prospective database of all adult patients undergoing placement of central venous access in the outpatient clinic of the Wake Forest University Baptist Medical Center. This database revealed that during the years 1996 and 1997, long-term central venous catheter placement was attempted in 589 adult patients in the outpatient clinic. Technical success was achieved in 558 patients (92%). This included 278 tunneled catheters and 280 totally implanted devices. Repositioning of the catheter tip was required in 16 patients (2.9%). The incidence of pneumothorax was 1.9 per cent. Late complications, including infection and thrombosis, occurred in 9 per cent. The average procedure-related charge for placement of a single-lumen central venous port in the outpatient clinic was $1691 versus $4559 in the operating room and $3890 in the radiology department. We conclude that routine placement of long-term central venous access devices in the outpatient clinic, without the use of real-time imaging, yields acceptable success rates and may have economic advantages over procedures performed in the operating room or radiology department.

hSK4/hIK1, a calmodulin-binding KCa channel in human T lymphocytes. Roles in proliferation and volume regulation

Human T lymphocytes express a Ca2+-activated K+ current (IK), whose roles and regulation are poorly understood. We amplified hSK4 cDNA from human T lymphoblasts, and we showed that its biophysical and pharmacological properties when stably expressed in Chinese hamster ovary cells were essentially identical to the native IK current. In activated lymphoblasts, hSK4 mRNA increased 14.6-fold (Kv1.3 mRNA increased 1.3-fold), with functional consequences. Proliferation was inhibited when Kv1.3 and IK were blocked in naive T cells, but IK block alone inhibited re-stimulated lymphoblasts. IK and Kv1.3 were involved in volume regulation, but IK was more important, particularly in lymphoblasts. hSK4 lacks known Ca2+-binding sites; however, we mapped a Ca2+-dependent calmodulin (CaM)-binding site to the proximal C terminus (Ct1) of hSK4. Full-length hSK4 produced a highly negative membrane potential (Vm) in Chinese hamster ovary cells, whereas the channels did not function when either Ct1 or the distal C terminus was deleted (Vm approximately 0 mV). Native IK (but not expressed hSK4) current was inhibited by CaM and CaM kinase antagonists at physiological Vm values, suggesting modulation by an accessory molecule in native cells. Our results provide evidence for increased roles for IK/hSK4 in activated T cell functions; thus hSK4 may be a promising therapeutic target for disorders involving the secondary immune response.

Vascularized iliac bone graft for displaced femoral neck fractures in young adults

From November 1989 to September 1994, a total of 26 patients (18 men and 8 women) with acute displaced femoral neck fractures were treated with closed reduction and Knowles pinning combined with vascularized iliac bone grafting. Mean patient age was 37.5 years (range: 24-48 years). The mean time interval from injury to surgery was 3.6 days (range: 1-10 days). One patient experienced loss of the reduction at 6 weeks postoperatively and subsequently went on to hip replacement. Mean follow-up for the remaining 25 patients was 56.2 months (range: 20-78 months). All fractures united within 4 months. The average union time was 3.3 months. Plain radiographs confirmed the presence of avascular necrosis in 2 patients during the final follow-up; 1 of these patients developed systemic lupus erythematous 1 year after the fracture and had been treated with high doses of corticosteroid. Functional and radiographic results were satisfactory in the remaining patients.

Morphological alterations associated with the cytotoxic and cytostatic effects of citric acid on cultured human dental pulp cells

Citric acid exerts potential harmful effects on the pulp when used for root surface demineralization, smear layer removal, and dentin etching. Using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay, we found that incubation of cultured human dental pulp cells in medium containing 0.5% (pH 4.74) or 1.0% (pH 3.42) of citric acid for 2 h lead to 25% and 48% of cell death, respectively. Cytotoxicity of citric acid was associated with its acidity. Exposure of cells to pure 1% citric acid (pH 2.26) for 60 s lead to immediate cell death. Cytotoxicity was usually preceded by cell retraction, cell surface blebbing, and finally uptake of trypan blue, implicating the presence of cell membrane damage. A medium containing 0.05% citric acid can retard the growth of pulp cells. These results indicate that adequate protection of the pulp is important, especially when the remaining dentin is thin in deep carious lesions or in the presence of accessory canals on the root surface.