Optimal Dose of Hypertonic Saline/Dextran in Hemorrhaged Swine

BACKGROUND

Hypertonic saline/dextran (HSD) fluid resuscitation has been demonstrated to be effective in alleviating the adverse effects of hemorrhagic hypotension. The optimal dose of HSD has not been defined.

METHODS

he comparative effectiveness of various dosages of HSD for the treatment of severe hemorrhage was investigated in conscious swine bled 46 mL/kg over 15 minutes, a lethal procedure. Five minutes after the completion of hemorrhage, animals were treated with 1, 2, 4, or 11.5 mL/kg HSD and observed over the next 96 hours.

RESULTS

The 11.5-mL dose resulted in 100% survival, which was statistically superior to the 1- and 2-mL doses but not the 4-mL dose. Survival incidences with 4, 2, and 1 mL/kg were 83%, 64%, and 13%, respectively.

CONCLUSION

In terms of survival time, the 11.5- and 4-mL/kg doses were not significantly different. Therefore, optimum resuscitative effectiveness of HSD is achieved within the dose range of 4 to 11.5 mL/kg.

Hydroxyurea in combination with didanosine and stavudine in antiretroviral-experienced HIV-infected subjects with a review of the literature

The safety and efficacy of hydroxyurea with didanosine in combination with stavudine in nucleoside reverse-transcriptase inhibitor (NRTI)-experienced patients was investigated. Entry criteria included HIV-1 infected, NRTI-experienced adults, with CD4(+) counts 50-550 cells/mm(3) and viral loads >or=12,500 copies/mL. Subjects were treated with didanosine 200 mg twice a day (BID), stavudine 40 mg BID, and hydroxyurea 1000 mg daily for 16 weeks. Thirty-one HIV-1 subjects with mean bDNA viral load 1x10(5) log(10) copies/mL and mean CD4(+) T-cell counts of 231 cells/mm(3) were enrolled. A 1.3 log(10) decrease in mean viral load was seen at 12 weeks of therapy. Prior didanosine use resulted in a more rapid response to therapy compared with prior zidovudine use. Side effects consisting of neutropenia, pancreatitis, and peripheral neuropathy occurred in four subjects and resolved upon withdrawal of therapy. This non-randomized study in subjects with a mean CD4(+) T-cell count of 230 cells/mm(3) demonstrates the antiviral activity of hydroxyurea+didanosine and stavudine. Toxicities related to therapy need to be followed closely. The results support the need for a randomized, prospective study to determine the safety and efficacy of hydroxyurea plus didanosine in antiretroviral-experienced patients with CD4(+) cell counts below 300 cells/mm(3).

Efficacy of hypertonic saline dextran fluid resuscitation for patients with hypotension from penetrating trauma

BACKGROUND

The purpose of this study was to assess whether the administration of hypertonic saline dextran (HSD) was detrimental when administered to patients who were hypotensive because of penetrating injuries to the torso. The administration of HSD causes an immediate and sustained increase in blood pressure that could contribute to an increase in bleeding in the presence of uncontrolled hemorrhage. We prospectively designed a series of questions to be addressed by a meta-analysis of individual patient data using a computerized data file and case report forms from a multicenter study of HSD.

METHODS

The investigators were "blind" as to the treatment the patient received. Patients (n = 230) with penetrating injuries to the torso were studied as to survival until discharge. The patients were administered 250 mL of HSD or normal saline (standard of care [SOC]) as the initial fluid therapy.

RESULTS

Of the 120 patients treated with HSD, 82.5% survived compared with 75.5% for 110 SOC patients (p = 0.19). Sixty-eight percent (n = 157) of these patients required surgery. HSD treatment (n = 84) in this population improved survival, 84.5% compared with 67.1% with SOC (n = 73) (p = 0.01). HSD resulted in an increase in blood pressure and a reduction in hematocrit, with no differences noted in fluid requirements or indices of clotting.

CONCLUSION

For patients with penetrating injuries to the torso that result in hypotension, initial fluid resuscitation with HSD is beneficial in improving survival, especially if surgery is subsequently required.

Seroprevalence of Kaposi's sarcoma-associated herpesvirus infection among blood donors from Texas

PURPOSE

Kaposi's sarcoma-associated herpesvirus (KSHV), a gammaherpesvirus recently discovered among AIDS patients with Kaposi's sarcoma, is a potential candidate for screening in blood and plasma donors. While a number of studies have assessed KSHV infection among U.S. blood donors, larger-scale population-based studies would be necessary to develop more refined estimates of the magnitude and variation of KSHV infection across different geographic regions of the U.S. blood supply. The goal of the present study, therefore, was to determine the seroprevalence of KSHV infection and to assess demographic correlates of KSHV infection among south Texas blood donors.

METHODS

KSHV infection was determined using specific serologic assays that measure antibodies to KSHV latent and lytic antigens.

RESULTS

The overall seroprevalence of KSHV in Texas blood donors (15.0%) is substantially higher than previously reported among blood donor and general population samples in the United States. This high rate of KSHV infection persisted across most of the sociodemographic subgroups under study but was particularly elevated among participants with less than a high school education. The infection rate also increased linearly with age.

CONCLUSIONS

The elevated infection rate reported in the present study suggests that screening methods to detect KSHV infection in blood donors should be considered. In view of the etiologic role of KSHV for several malignancies, it would be important for future studies to directly assess the risk of KSHV transmission via blood transfusion.

A prospective, controlled study of the effects of hormonal contraception on bone mineral density

OBJECTIVE

To compare the effect of depot medroxyprogesterone acetate (DMPA) and two types of oral contraceptives (OC) on bone mineral density (BMD) among women 18-33 years of age with those not using hormonal contraception.

METHODS

Data from 155 women were analyzed. Depot medroxyprogesterone acetate was administered to 33 women; 63 women who chose oral contraception were randomly assigned to receive either a norethindrone-containing pill (n = 28) or a desogestrel-containing pill (n = 35). Fifty-nine women who did not use hormonal contraception served as controls. Lumbar spine BMD was determined using dual-energy x-ray absorptiometry at baseline and after 12 months of contraceptive use. We analyzed method-related percent change in BMD while controlling for body mass index, calcium intake, exercise, and smoking. We had approximately 90% power to detect a 2.5% difference between any two groups.

RESULTS

Users of DMPA experienced a mean BMD loss of 2.74% over 12 months compared with controls who sustained a 0.37% loss (P = .01). Users of OCs generally demonstrated a gain (2.33% for norethindrone-containing pills, 0.33% for desogestrel-containing pills), which was different from controls among users of norethindrone-containing pills (P = .01), but not among users of desogestrel-containing pills (P = .99). Observed changes in BMD among DMPA users differed from women who used either type of pill (P < .002).

CONCLUSION

Depot medroxyprogesterone acetate has an adverse effect on BMD, in comparison with OCs or nonhormonal methods, when used for 12 months. Results must be interpreted cautiously until it is determined whether these effects endure or are reversible.

Changes in exploratory behavior as a measure of chronic central pain following spinal cord injury

Spinal cord injury (SCI) produces abnormal pain syndromes in patients that lead to changes in evoked and spontaneous behaviors. To test if a spontaneous component of pain-like behavior could be measured in a rodent model of chronic central pain (CCP), exploratory behavior (rearing events, rearing time, active time, rest time, distance traveled, and total activity) of adult male rats, subjected to sham surgery or spinal cord contusion injury treated with either vehicle (saline) or gabapentin (30 mg/kg, i.p.), was recorded. SCI was produced at spinal segment T10 using the NYU impactor device (10-g rod, 2.0-mm diameter, 12.5-mm drop height). Activity measures were collected on postsurgical days (PSD) 14, 28, and 60, and compared to presurgical activity. Sham control activity was not significantly different compared to presurgical activity in any measured parameter. SCI vehicle-treated rats demonstrated a significant decrease in total rearing time on PSD 14 and by PSD 28 significant differences in total activities where seen in all parameters measured. SCI gabapentin-treated rats did not display differences in total rearing time until PSD 28 and a significant difference in total activity of all measured parameters was not seen until PSD 60. No difference in hindlimb locomotor ability between SCI groups or sedation effects of gabapentin was found using open field BBB scores. We interpret the differences in exploratory behavior to reflect spontaneous behavioral changes due to CCP since (1) when locomotor ability was greatest, activity was lowest and (2) gabapentin attenuates the temporal decrease in activity. This study demonstrates that spontaneous as well as evoked behaviors may be used to evaluate CCP following SCI.

HIV Seroprevalence among newly incarcerated inmates in the Texas correctional system

PURPOSE

The seroprevalence of HIV infection was examined among a sample of incoming inmates in the Texas Department of Criminal Justice prison system. Rates were compared across sociodemographic factors and three types of prison facilities: substance abuse felony punishment units (SAFPs), state jails, and prisons.

METHODS

The study sample consisted of 4386 incoming inmates incarcerated for any duration, dating from November 1, 1998, to May 31, 1999.

RESULTS

Among males, inmates entering state jails had a higher HIV infection rate (3.7%) than either inmates entering prisons (1.9%) or those entering SAFPs (0.5%). Among females, inmates entering prisons had a higher rate of infection (9.3%) than those entering state jails (2.5%) or SAFPs (4.5%).

CONCLUSIONS

Although a number of blinded HIV seroprevalence studies have been conducted in U.S. prison systems, scarce information is currently available on HIV infection rates in alternative correctional facilities. The present study shows that HIV seropositivity varied substantially according to race, gender, and prison facility type. Given the shorter incarceration periods for inmates held in alternative facilities, understanding how infection rates vary according to type of incarceration facility holds particular public health relevance.

Effects of an isoflavone-free soy diet on ovarian hormones in premenopausal women

Soy intakes have been associated with reduced rates of breast cancer in some Asian populations. The isoflavones daidzein and genistein and other components of soybeans may modulate endocrine function and lead to beneficial health effects. This study determined the effects of a soy diet containing minimum amounts of isoflavones on circulating levels of ovarian hormones and gonadotropins. Nine healthy, regularly cycling women consumed a constant soya-containing diet on a metabolic unit starting on day 2 of a menstrual cycle until day 2 of the next cycle. The soy diet was calculated to maintain constant body weight and included a 36-oz portion of soymilk that provided 334 kilocalories and less than 5 mg/day of total isoflavones. The energy distribution of the soy diet was 35.9% fat, 14.0% protein, and 49.8% carbohydrate whereas the home diets averaged 39% fat, 16.6% protein, and 42.5% carbohydrate. For the group, the soya diet provided more carbohydrate (P = 0.002) and less protein (P = 0.005) than the home diets. Daily consumption of the soya diet reduced daily circulating levels of 17beta-estradiol over the entire menstrual cycle by 20% (P < 0.01, paired t test, two-tailed) and progesterone by 33% (P < 0.0001) compared with levels during the home diet period, but had no effect on LH, FSH, or sex hormone-binding globulin. The decreases in follicular phase 17beta-estradiol during the soy diet can be accounted for by changes in energy intakes, nutrient density, and fiber intake, whereas changes in luteal phase 17beta-estradiol were most strongly associated with differences in fiber intake. Changes in progesterone levels were most strongly associated with changes in protein intake and much less with other nutrients. Isoflavones were not detectable in plasma and urine during either the soy or home diet periods. These results suggest that at least under the conditions of this study, a soy diet with low levels of isoflavones and low energy intake from protein can reduce circulating ovarian steroids without altering gonadotropins. Our results are consistent with previous studies showing decreased ovarian hormone levels and decreased risk of breast cancer in populations consuming soya diets and an inverse relationship between animal protein intake and breast cancer risk and, therefore, may have implications for breast cancer prevention.

Effect of nasal continuous positive airway pressure on neuropsychological function in sleep apnea-hypopnea syndrome. A randomized, placebo-controlled trial

A placebo-controlled, partial cross-over, double-blind, randomized study was performed with 46 adults with sleep apnea-hypopnea syndrome (SAHS) to determine the effect of therapeutic and subtherapeutic (0-1 cm H(2)O) nasal continuous positive airway pressure (CPAP) treatment on polysomnographic and neuropsychological testing. The following neuropsychological tests were administered: Geriatric Depression Scale, Trail Making A and B, Digit Span Test Forward and Backward, Epworth Sleepiness Scale, SteerClear, Digit Symbol, Controlled Oral Word Association, and Complex Figure Recall. Compared with results without CPAP, subtherapeutic CPAP did not affect any measured polysomnographic parameter. Comparison of neuropsychological test results obtained between the initial periods of effective treatment (Group 1, 16.1 d; Group 2, 19.6 d; p = NS) in all subjects showed significant improvements in Digit Symbol, Digit Span Backward, and Complex Figure tests. However, there were no group differences in changes in test results during the period when one group was on effective CPAP and the other on ineffective CPAP (Group 1, 16.1 d; Group 2, 13.9 d; p = NS). The results indicate the feasibility and importance of using ineffective CPAP as a placebo treatment and the importance of including a placebo control in studies evaluating the effect of treatment on neuropsychological function in SAHS.

A flow cell assay for evaluation of whole cell drug efflux kinetics: analysis of paclitaxel efflux in CCRF-CEM leukemia cells overexpressing P-glycoprotein

P-glycoprotein (Pgp) mediates drug accumulation defects in malignant cells in vitro. It confers resistance to multiple drugs including paclitaxel, an agent useful in treating malignancies including acute leukemia. Pgp-mediated drug resistance appears to be due to primary active drug-transport as well as other effects on membrane permeability, but the relative contribution of each is unclear. Flow cells are useful for differentiating transport-mediated efflux from altered membrane permeability, but their utility is limited to attached cells. We developed a novel flow cell to study drug efflux kinetics in suspension culture cells and examined paclitaxel efflux in resistant CEM/VLB100 leukemia cells, which overexpress Pgp, compared with its sensitive CEM parent line. Paclitaxel efflux from both cell lines was described by bi-exponential kinetics. The predominant initial rapid component increased linearly with paclitaxel concentration, consistent with passive efflux, and was faster in CEM/VLB100 than CEM cells. The slow terminal component of efflux was also more rapid for CEM/VLB100 than CEM, and was saturable (V(max)= 9.1 +/- 1.1 versus 3.5 +/- 0.3 pmol/min/10(7) cells, respectively) at a lower paclitaxel concentration than the parental CEM cells (k(m) = 63 +/- 46 nM versus 144 +/- 56 nM, respectively). In CEM/VLB100 cells, this saturable component was inhibited by verapamil and was temperature-sensitive, consistent with Pgp-mediated transport. Verapamil also inhibited the rapid component of efflux, suggesting additional effects on membrane permeability. Our studies show that the present technique is useful for studying drug transport and that effects of Pgp on membrane permeability contribute significantly to the net drug-accumulation defect.

Compliance with antidepressant medication among prison inmates with depressive disorders

This study assessed correlates of antidepressant medication compliance among 5,305 inmates of the Texas Department of Criminal Justice prison system who were diagnosed as having a depressive disorder. Use of tricyclic antidepressants, male gender, and higher age were all positively associated with medication compliance scores. This investigation provided no evidence that broader use of selective serotonin reuptake inhibitors would improve adherence to pharmacologic treatment in this population. The results also suggest that correctional administrators may wish to target younger inmates and women with interventions to improve medication compliance.

Decreased ovarian hormones during a soya diet: implications for breast cancer prevention

Ovarian hormones are biomarkers for breast cancer risk. Soybean consumption may be responsible in part for lower levels of ovarian hormones and decreased rates of breast cancer in women in Asia compared with Western populations. Soybeans contain a significant amount of the isoflavones daidzein and genistein, which are weak estrogens. The purpose of this study was to determine whether soya feeding decreases circulating levels of ovarian hormones and gonadotropins. Ten healthy, regularly cycling women consumed a constant soya-containing diet on a metabolic unit, starting on day 2 of a menstrual cycle until day 2 of the next cycle. Blood and urine samples were obtained daily for one menstrual cycle before and during soy feeding. The diet was calculated to maintain constant body weight, included 400 kilocalories from a 36-ounce portion of soymilk, and provided 113-207 mg/day (154.0+/-8.4 mg/day, mean +/- SE) of total isoflavones. For the group, the soya diet provided more carbohydrate and less protein than the home diets. Daily consumption of the soya diet reduced circulating levels of 17beta-estradiol by 25% (P<0.01, Wilcoxon signed rank test, two-tailed) and of progesterone by 45% (P<0.0001) compared with levels during the home diet period but had no effect on luteinizing hormone or follicle-stimulating hormone. Mean menstrual cycle length did not change during the soya diet; a slight decrease in mean luteal cycle length was marginally statistically significant (P = 0.06). Urinary excretion of isoflavones was 33.8+/-5.3 mg/day (mean +/- SE) and when expressed as percentage of intake, varied substantially (21.9+/-3.3% of intake; range, 9.1-36.7%) among the subjects. Mean daily serum levels of daidzein and genistein (free and conjugated forms) 15 h after soymilk were 2.89+/-0.53 microg/ml and 0.85+/-0.22 microg/ml, respectively, indicating systemic bioavailability of these substances. Secondary analyses by multiple regression showed that decreases in follicular and luteal phase 17beta-estradiol levels were positively associated with urinary isoflavone excretion, an association affected by age, and were inversely associated with decreases in protein intake. Decreases in progesterone levels during the soya diet were inversely associated with increases in intakes of genistein and were affected by the interaction of the intakes of daidzein with energy or with fiber. Consumption of an isoflavone-containing soya diet reduced levels of ovarian steroids in normal women over the entire menstrual cycle without affecting gonadotropins. This suggests that at least under the conditions of this study, soya-induced reductions of circulating ovarian steroids are not mediated by gonadotropins. Decreases in ovarian hormones are related to isoflavones contained in soy and also to energy intake and other components such as protein and fiber but not fat. Our results may explain decreased ovarian hormone levels and decreased risk of breast cancer in populations consuming soya diets and have implications for reducing breast cancer risk by dietary intervention.

DNA adducts of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) in fetal tissues of patas monkeys after transplacental exposure

Transplacental genotoxicity of the heterocyclic amine food-derived mutagen/carcinogen 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) has been investigated by (32)P-postlabeling assay for IQ-DNA adducts in maternal liver, placenta, and several fetal tissues of patas monkeys, after exposure to 15, 35, or 50 mg/kg IQ near the end of gestation or to the highest dose in the first or second trimester. Dose-dependent adduct formation occurred in all tissues, with the highest levels occurring in maternal liver. Adduct amounts were similar among fetal tissues and placenta, except for lower levels in fetal brain and slightly more adducts in fetal liver. Adducts in placenta, fetal liver, lung, kidney, skin, and adrenal gland, but not in maternal liver or fetal brain, increased significantly as gestation progressed. Pretreatment with phenobarbital, which induces CYP enzymes that detoxify IQ, decreased adducts in maternal liver and possibly placenta, but not in fetal tissues. The CYP inducer beta-naphthoflavone caused a significant increase in IQ-DNA adducts in fetal lungs. Regression analysis suggested that IQ activation in maternal and fetal liver and possibly placenta contributed to adduct formation in fetal tissues; adducts in placenta and/or fetal liver were strong predictors for those in most fetal tissues. The results indicate that exposure of pregnant primates to IQ results in DNA adduct formation in most fetal tissues, especially late in gestation; that upregulation of maternal detoxification does not provide fetal protection; and that adducts in placenta indicate adduct levels in fetal tissues.

A case-control study of anatomic changes resulting from sexual abuse

OBJECTIVE

Our goal was to identify vulvar and hymenal characteristics associated with sexual abuse among female children between the ages of 3 and 8 years.

STUDY DESIGN

Using a case-control study design, we examined and photographed the external genitalia of 192 prepubertal children with a history of penetration and 200 children who denied prior abuse. Bivariate analyses were conducted by chi(2), the Fisher exact test, and the Student t test to assess differences in vulvar and hymenal features between groups.

RESULTS

Vaginal discharge was observed more frequently in abused children (P =.01). No difference was noted in the percentage of abused versus nonabused children with labial agglutination, increased vascularity, linea vestibularis, friability, a perineal depression, or a hymenal bump, tag, longitudinal intravaginal ridge, external ridge, band, or superficial notch. Furthermore, the mean number of each of these features per child did not differ between groups. A hymenal transection, perforation, or deep notch was observed in 4 children, all of whom were abused.

CONCLUSION

The genital examination of the abused child rarely differs from that of the nonabused child. Thus legal experts should focus on the child's history as the primary evidence of abuse.

Punctate midline myelotomy for the relief of visceral cancer pain

OBJECT

This study offers clinical support for the concept that neurosurgical interruption of a midline posterior column pathway by performing a punctate midline myelotomy (PMM) provides significant pain relief without causing adverse neurological sequelae in cancer patients with visceral pain refractory to other therapies.

METHODS

A PMM of the posterior columns was performed in six cancer patients in whom visceral pain had been refractory to other therapies. The cause of the visceral pain was related to residual, progressive, or recurrent local cancer or postirradiation effects. Clinical efficacy of the procedure was examined by comparing patient pain ratings and narcotic usage pre- and post-PMM. Follow-up periods ranged from 3 to 31 months. Examination of the results indicates a significant reduction in pain ratings as well as a significant reduction in daily narcotic use. No adverse neurological effects were observed. One spinal cord has been recovered for postmortem examination.

CONCLUSIONS

These findings provide corroborating clinical evidence for the existence of a newly recognized midline posterior column pathway that mediates the perception of visceral pelvic and abdominal pain. Preliminary data indicate that significant pain relief can be obtained following PMM with minimal neurological morbidity and suggest that the procedure may provide an alternative treatment modality for cancer-related pain in patients in whom adequate pain control with narcotics cannot be achieved or narcotic side effects cannot be tolerated.

Increased urinary excretion of 2-hydroxyestrone but not 16alpha-hydroxyestrone in premenopausal women during a soya diet containing isoflavones

Asian diets high in soy are associated with lower risk for breast cancer compared with Western diets. Moreover, higher levels of two putative carcinogenic metabolites of 17beta-estradiol, 4- and 16alpha-hydroxyestrogen, and lower amounts of anticarcinogenic metabolites, 2-hydroxyestrogens, have been associated with greater breast cancer risk. In this study, we tested the hypothesis that consumption of a soya diet containing the weakly estrogenic isoflavones genistein and daidzein may alter the metabolism of 17beta-estradiol to 2- and 16alpha-hydroxylated products. Eight pre-menopausal women were placed on a soya-containing, constant diet in a metabolic unit. The diet provided 400 kilocalories from soymilk and 113-202 mg/day (158 +/- 26 mg/day, mean +/- SD) isoflavones daily for a complete menstrual cycle. After a washout period of 4 months, the subjects consumed the same diet, but with soymilk that contained <4.5 mg/day isoflavones ("isoflavone-free"). Urine samples were collected for 24 h daily for the entire cycle during each soya diet period for the analysis of daidzein, genistein, and 2- and 16alpha-hydroxyestrone. Subjects excreted measurable amounts of daidzein (11.6-39.2 mg/day) and genistein (2.9-18.2 mg/day) during the isoflavone-rich soya diet but not during the isoflavone-free soya diet. The diet rich in isoflavones increased the cycle mean daily urinary excretion of 2-hydroxyestrone (averaged over the entire cycle) from 11.6 +/- 2.06 to 17.0 +/- 2.96 nmol/12-h (P = 0.03), a 47% increase. However, the mean daily excretion of 16alpha-hydroxyestrone did not change (7.0 +/- 1.14 nmol/12-h during the isoflavone-free and 7.7 +/- 1.25 nmol/12-h during the isoflavone-rich diet; P = 0.36). The ratio of 2-hydroxyestrone to 16alpha-hydroxyestrone was higher during the isoflavone-rich soya diet (2.6 +/- 0.34) than during the isoflavone-free diet (2.0 +/- 0.32; P = 0.01), a 27% increase. These results suggest that soya isoflavones increase the metabolism of endogenous estrogens to the protective 2-hydroxylated estrogens in women, and this may play an important role in lowering 17beta-estradiol levels and the long-term risk for breast cancer.

Meta-analysis of pediatric tympanoplasty

OBJECTIVE

To determine which preoperative conditions or surgical techniques may influence the success of tympanoplasty in the pediatric population.

DATA SOURCES

A MEDLINE search of the English-language literature from 1966 to May 1997 was conducted using the search terms pediatric or child and tympanoplasty or myringoplasty.

STUDY SELECTION

Articles that provided age-specific data on tympanoplasty or myringoplasty were included. Of the original 651 studies retrieved, 30 were accepted for inclusion. The principal reason for exclusion was inability to separate adult and pediatric results in series that combined both patient populations.

DATA EXTRACTION

Success was defined as an intact tympanic membrane for the purpose of this review. Data were tabulated by consensus of 2 reviewers.

DATA SYNTHESIS

The effect of surgical technique, prior adenoidectomy, presence of active infection, size of perforation, status of the contralateral ear, age, and eustachian tube function on healing of the tympanic membrane after surgery was assessed. Only those studies providing data on a given parameter of interest could be included when comparing each variable. Weighted means were compared and subjected to sensitivity analysis. Simple linear regression analysis was used to assess the effect of age on outcome.

CONCLUSIONS

Greater success in healing of the tympanic membrane following tympanoplasty in children is seen with advancing age. None of the other parameters studied was shown to be a significant predictor of success. Guidelines for reporting results of tympanoplasty are presented.

Slow intramural heating with diffused laser light: A unique method for deep myocardial coagulation

BACKGROUND

Catheter ablation of postinfarction ventricular tachycardia (VT) may be limited by insufficient myocardial coagulation or excessive endocardial or epicardial damage. We propose that volumetric heating restricted to intramural sites may improve the outcome and safety of this procedure, especially if delivered at rates that enhance heat conduction and forestall adverse tissue changes.

METHODS AND RESULTS

A novel optical fiber with a diffusing tip for direct intramural, volumetric laser heating was tested via thoracotomy and percutaneously in normal dogs. Low-power (2.0- to 4.5-W) diode laser light (805 nm) diffused within tissue induced large lesions but no visible surface damage, mural thrombi, or transmural perforation. Mean lesion depth approximated tip length (10 mm). Mean lesion widths in the thoracotomy and percutaneous groups were 5.8+/-0.5 to 9.1+/-0.84 mm and 5.2+/-0.85 to 7.9+/-1.1 mm, respectively, depending on the light dose. Mean volumes in the percutaneous group were 1006+/-245 to 2471+/-934 mm. ST-segment depression, appearing in unfiltered bipolar electrograms recorded from the guiding catheter, was specific for lesion induction. All dogs survived the protocol, which included a 1-hour observation period. In cross section, lesions were elliptical to spherical and characterized by extensive contraction-band necrosis abruptly bordering viable tissue. No platelets or fibrin adhered to the endocardium.

CONCLUSIONS

Slow, volumetric, and direct intramyocardial heating induces large, deep lesions without hazardous tissue damage. Such heating might cure postinfarction VT more successfully and safely than present techniques. Further testing and development of this method seem warranted.

Trail Making Test: issues in Normative Data Selection

The Trail Making Test (TMT) is one of the most frequently administered neuropsychological instruments, having been used in the evaluation of cognitive dysfunction for over 50 years. Despite the measure's extensive clinical use and proliferation of research, no comprehensive review of the adult TMT normative literature is available. This report examines the available TMT normative reports and provides a summary of the sample characteristics. Significant variability between studies precludes the use of metanorms. Clinically, these findings indicate that biased results may be obtained if the most appropriate normative data set is not used and underscore the importance of identifying the normative comparison group that approximates the relevant patient characteristics. To assist the clinician, selected normative reports (based on certain exclusionary parameters) have been compiled for three nonclinical comparison groups: (a) an adolescent and young adult group (ages 15-24), (b) an adult group (ages 20-54), and (c) an older adult group (ages 55-85). Results are discussed in terms of the influence of moderator variables on TMT performance and other factors, such as procedural differences in administration, that may account for the significant variability between normative samples.

Efficacy of hypertonic 7.5% saline and 6% dextran-70 in treating trauma: a meta-analysis of controlled clinical studies

BACKGROUND

Individual trials of small-volume resuscitation of 7.5% NaCl (HS) with and without 6% dextran 70 (HSD) for the treatment of trauma have failed to provide convincing evidence of efficacy. We performed a meta-analysis to evaluate the effects of HS and HSD on survival until discharge or for 30 days. We identified eight double-blinded, randomized controlled trials of HSD and six trials of HS. In all cases, administration of 250 ml of HSD or HS was compared with a control group administration of 250 ml of isotonic crystalloid for the treatment of hypotension either in the field or at admission to the emergency department.

METHODS

A fixed-effects meta-analysis was performed with the Mantel-Haenszel method of combining results from multiple studies.

RESULTS

Overall, HS was not effective in improving survival with a weighted mean difference in survival of the HS group versus the isotonic control group equal to 0.6%. The results with HSD were more positive, with an increase in survival in seven of eight trials. The mean difference in survival rates favoring HSD (n = 615) over controls (n = 618) was 3.5% (p = 0.14, two-tailed; p = 0.07, one-tailed). The odds ratio was estimated to be 1.20 in favor of HSD with a 95% confidence interval of 0.94 to 1.57.

CONCLUSIONS

The meta-analysis of the available data shows that HS is not different from the standard of care and that HSD may be superior.

Individual patient cohort analysis of the efficacy of hypertonic saline/dextran in patients with traumatic brain injury and hypotension

BACKGROUND

Resuscitation with hypertonic saline/dextran (HSD) has been suggested to be efficacious in patients who have traumatic brain injury and are hypotensive. We undertook a cohort analysis of individual patient data from previous prospective randomized double-blinded trials to evaluate improvements in survival at 24 hours and discharge after initial treatment with HSD in patients who had traumatic brain injury (head region Abbreviated Injury Score > or = 4) and hypotension (systolic blood pressure < or = 90 mm Hg).

METHODS

All variables and end points were defined before initiation of data handling. Investigators were blind as to the treatment. Case report forms were received from six studies. Of these, 223 patients met the inclusion for traumatic brain injury. Comparisons between HSD and standard of care were made using stratified analysis and logistic regression to assess efficacy, confounding, and interaction. Potential confounding variables of pre-fluid treatment, Glasgow Coma Scale score (3-8 vs. 9-15), injury type, and systolic blood pressure can be considered a priori factors that were known before randomization. Effects of the various trials was also considered.

RESULTS

Treatment with HSD resulted in a survival until discharge of 37.9% (39 of 103) compared with 26.9% (32 of 119) with standard of care (p = 0.080). Using logistic regression, adjusting for trial and potential confounding variables, the treatment effect can be summarized by the odds ratio of 2.12 (p = 0.048) for survival until discharge.

CONCLUSIONS

Patients who have traumatic brain injuries in the presence of hypotension and receive HSD are about twice as likely to survive as those who receive standard of care.

Effects of soya consumption for one month on steroid hormones in premenopausal women: implications for breast cancer risk reduction

Soybean consumption is associated with reduced rates of breast, prostate, and colon cancer, which is possibly related to the presence of isoflavones that are weakly estrogenic and anticarcinogenic. We examined the effects of soya consumption on circulating steroid hormones in six healthy females 22-29 years of age. Starting within 6 days after the onset of menses, the subjects ingested a 12-oz portion of soymilk with each of three meals daily for 1 month on a metabolic unit. Daily isoflavone intakes were approximately 100 mg of daidzein (mostly as daidzin) and approximately 100 mg of genistein (mostly as genistin). Serum 17 beta-estradiol levels on cycle days 5-7, 12-14, and 20-22 decreased by 31% (P = 0.09), 81% (P = 0.03), and 49% (P = 0.02), respectively, during soya feeding. Decreases persisted for two or three menstrual cycles after withdrawal from soya feeding. The luteal phase progesterone levels decreased by 35% during soya feeding (P = 0.002). Dehydroepiandrosterone sulfate levels decreased progressively during soya feeding by 14-30% (P = 0.03). Menstrual cycle length was 28.3 +/- 1.9 days before soymilk feeding, increased to 31.8 +/- 5.1 days during the month of soymilk feeding (P = 0.06), remained increased at 32.7 +/- 8.4 days (P = 0.11) at one cycle after termination of soymilk feeding, and returned to pre-soya diet levels five to six cycles later. These results suggest that consumption of soya diets containing phytoestrogens may reduce circulating ovarian steroids and adrenal androgens and increase menstrual cycle length. Such effects may account at least in part for the decreased risk of breast cancer that has been associated with legume consumption.

Altered kinetics and extent of urinary daidzein and genistein excretion in women during chronic soya exposure

Soybean consumption may be protective for breast cancer, possibly due in part to the presence of the isoflavones daidzein and genistein, which are weakly estrogenic. The metabolism and disposition of these phytoestrogens during chronic soya exposure were studied on a metabolic unit. Six healthy 22- to 29-year-old women consumed an unrestricted hospital diet for most of the study and ingested 12 oz of soymilk with each meal for one month. At two-week intervals, excretion of isoflavones in urine was studied, during which time the subjects consumed a constant basal diet for three to four days, ingested the full daily 36-oz portion of soymilk within 30 minutes each day for one to two days, and collected urine continuously. Urinary recovery of genistein [initially 23.9 +/- 17.3% (SD) of ingested genistin + genistein], daidzein (initially 66.2 +/- 23.5% of ingested daidzin + daidzein), and equol (initially 28% of the ingested precursors daidzin + daidzein in 1 subject and < 1% in 5 subjects) decreased progressively over four weeks of daily soya ingestion by 42% for genistein (p < 0.05) and 31% for daidzein (p < 0.01) but increased by 3- to 100-fold for equol (4 subjects, p < 0.05). Total amounts excreted and peak levels were similarly affected. The absorption half-lives (t 1/2) for genistein and daidzein were initially 2.7 +/- 0.8 and 1.6 +/- 0.5 hours, respectively, and during four weeks of soymilk ingestion decreased to 2.0 +/- 0.6 (p = 0.04) and 1.4 +/- 0.2 hours (p = 0.06), respectively, suggesting more rapid absorption. The appearance t 1/2 of equol can be estimated for only one subject initially (2.9 hrs), but during four weeks of soya ingestion it could be estimated for three more subjects (4.7 +/- 2.3 hrs). The excretion t 1/2 values for genistein and daidzein were initially 6.7 +/- 0.8 and 4.4 +/- 0.7 hours, respectively, and during four weeks of soymilk ingestion decreased to 4.2 +/- 1.2 (p = 0.005) and 3.2 +/- 1.1 hours (p = 0.005), respectively, suggesting more rapid excretion. For equol, the excretion t 1/2 was initially 9.1 hours (1 subject), and after two and four weeks of soymilk ingestion it was 13.4 +/- 9.7 and 5.5 +/- 1.6 hours (4 subjects, p = 0.046, 2 wks vs. 4 wks), respectively. These results indicate that metabolism and disposition of ingested isoflavones are altered during chronic soya ingestion in women, perhaps from increased metabolic degradation to formation of nonisoflavone metabolites. Increased production of the longer- and stronger-acting estrogenic equol in some women during chronic soymilk ingestion may alter the estrogenic potency of dietary soya isoflavones.

Model selection techniques for the covariance matrix for incomplete longitudinal data

In longitudinal studies with incomplete data, where the number of time points can become numerous, it is often advantageous to model the covariance matrix. We describe several covariance models (for example, mixed models, compound symmetry, AR(1)-type models, and combination models) that offer parsimonious alternatives to unstructured sigma. We evaluate each covariance model with longitudinal data concerning cholesterol as the repeated outcome measure. We discuss strategies for deciding the 'best' model and show a graphical technique for judging goodness-of-fit of covariance models.

Altered time course of urinary daidzein and genistein excretion during chronic soya diet in healthy male subjects

Soybean consumption is associated with reduced rates of prostate and other cancers, possibly due in part to the presence of isoflavones. The metabolism and disposition of these soya-derived phytoestrogens after chronic soya exposure were studied on a metabolic unit in six healthy males (21-35 yrs of age) who consumed an unrestricted hospital diet and a 12-oz portion of soymilk with each meal for one month. The daily isoflavone intake was about 100 mg of daidzein (mostly as diadzin) and about 100 of mg of genistein (mostly as genistin). At two-week intervals, excretion of isoflavones in urine was studied, during which time the subjects consumed a constant basal diet for three to four days, ingested the full daily 36-oz portion of soymilk within 30 minutes each day for one to two days, and collected urine continuously. The urinary recovery of ingested diadzin plus daidzein (46.9 +/- 15.2%, mean +/- SD) and genistin plus genistein (14.6 +/- 9.2%) did not change with prolonged soya ingestion. The absorption half-lives (t1/2) for daidzein and genistein and the appearance t1/2 for equol (1 subject) were initially 1.5 +/- 0.4, 1.9 +/- 0.6, and 2.2 hours, respectively, and 2.5 +/- 1.1 (p = 0.06 compared with baseline) 1.4 +/- 0.9 (p = 0.03) compared with baseline), and 4.2 hours, respectively, during one month of soymilk ingestion. The excretion t1/2 for daidzein, genistein, and equol were initially 2.9 +/- 0.5, 3.8 +/- 0.7, and 5.2 hours, respectively, and 3.9 +/- 1.2 (p - 0.03), 5.5 +/- 1.6 (p = 0.02), and 9.7 hours, respectively, during one month of soymilk ingestion. These results indicate that chronic soya exposure did not induce significant changes in the metabolic pathways of isoflavones but altered the time courses of daidzein and genistein excretion. Thus chronic exposure to soya might prolong the tissue exposure to the presumed biologically active free and unconjugated forms of these isoflavones and thereby enhance their oncoprotective effects.

The effects of carrier gas composition on the performance of the Tec 6 desflurane vaporizer

The new Tec 6 desflurane vaporizer is an electrically heated, pressurized, electromechanically coupled dual-circuit blender. We hypothesized that carrier gas viscosity should affect the electromechanical coupling of the fresh gas and vapor circuits, and that desflurane output should vary with different carrier gases. In the first portion of the study, the performance of eight vaporizers was evaluated using a constant dial setting of 10% desflurane with four different carrier gases and three different fresh gas flow rates. In the second portion of the study, the carrier gas flow rate was maintained at 1, 5, or 10 L/min, and vaporizer output was analyzed at all integer dial settings from 1% to 18%. Vaporizer output was highest when oxygen was the carrier gas and lowest when nitrous oxide was the carrier gas. This effect was accentuated at low fresh gas flow rates and correlated with carrier gas viscosity. At a flow rate of 1.0 L/min with a constant dial setting of 10%, the averaged output from vaporizers was 10.3 +/- 0.66, 9.4 +/- 0.58, 8.7 +/- 0.52, and 8.1 +/- 0.44 vol% for 100% oxygen, air, 30% oxygen plus 70% nitrous oxide, and 100% nitrous oxide, respectively. With 100% nitrous oxide as the carrier gas at a flow rate of 1.0 L/min, the vaporizer delivered 2 vol% less than the dial setting at dial settings in excess of 12%. Differences between the analyzed concentration and the dial setting were most pronounced with high concentrations of nitrous oxide at low fresh gas flow rates.

Torque and pullout analysis of six currently available self-tapping and "emergency" screws

Insertional torque (IT), stripping torque (ST), and uniaxial pullout tests were performed to evaluate the effectiveness of six screw systems (Wurzburg, Techmedica, Synthes, Timesh, Steinhouser, Luhr) in thin porcine rib. The Timesh 2.2-mm self-tapping screw produced the largest insertional and stripping torque of all systems tested as well as the largest difference between the insertional and stripping torque. The Timesh emergency screw also had the largest insertional and stripping torque as well as the largest difference between the insertional and stripping torque. In pullout tests, the Timesh screw was found to be the most retentive. The overall data indicated that the ideal self-tapping screw should have the largest difference possible between drill size and external diameter, a channel, and at least three self-tapping threads for maximum retention.

Accuracy of quantification of mandibular condyle displacement in digitally subtracted linear tomograms

Using a TMJ skeletal phantom, we assessed validity and reliability of digitally subtracted linear tomographic images to quantify condylar position changes. Horizontally corrected frontal and lateral tomographic images were made with the condyle in a 'centred' position and displaced by 1, 2 and 3 mm increments in two of three directions (inferior, and posterior, or lateral). Film images were sequentially subtracted and then randomized so that observers were blinded to the amount and direction of condylar movement. Averages of three measurements of the dark bands representing condylar shifts were made using a digitizing tablet. The study utilized a nested design where the series of film images was subtracted twice and each subtraction was read twice by two examiners. We repeated the study with a second series of films treated in an identical manner. Average differences from expected values were similar for frontal and lateral techniques and all directions and increments of displacement. Typical average difference for any increment was less than 0.1 mm. Standard deviations in measures were similar across techniques and increments and were typically less than 0.1 mm. Significant variation in the absolute value of differences between measured and expected values by direction of condylar displacement was attributed to greater accuracy of registration on the vertical axis for frontal images. A significant source of variation in the study design element 'film set' was attributed to errors in repositioning the phantom.(ABSTRACT TRUNCATED AT 250 WORDS)

Digitally subtracted linear tomograms: three techniques for measuring condylar displacement

Using digital subtraction enhancement, we compared the accuracy of three tomographic technique variations for quantifying small changes of condylar position. A phantom made of skeletal material and an adjustable mechanical stage provided 0.1 mm positioning accuracy of the condylar segment. Linear tomographic images were made with the condyle in a centered position and at each of three 1 mm increments of displacement in two of three directions (inferior, and posterior or lateral). Variations for frontal views included arbitrary (+20 degrees) and individualized (+10 degrees) horizontal correction of the condylar axis. Variations for lateral views included the arbitrary and individualized correction and a fully corrected vertical (+5 degrees) and horizontal (+10 degrees) adjustment. Blinded observers made repeated measurements on randomized subtraction images with a digitizing tablet. Film images were subtracted twice, and each subtraction was read twice by two examiners. The study was repeated with a second series of films treated in an identical manner. Mean values for measurements, standard deviations, and absolute values of differences between measured and expected values were calculated for each subtraction. Analysis of variance identified statistically significant sources of variation in repositioning the phantom and producing exact displacements of the condyle. Average absolute value of differences from expected values were similar for the three techniques and for frontal and lateral orientations and increments of displacement. Typical absolute value of difference for any technique was 0.2 mm for posterior, 0.2 mm for lateral, and 0.1 mm for inferior displacements. Significantly greater accuracy of inferior displacement measures was attributed to greater accuracy of registration of the fossa in its cranio-caudal dimension.(ABSTRACT TRUNCATED AT 250 WORDS)

Accuracy of student self-evaluations of dental sealants

The purpose of this study was to (1) assess the accuracy of student self-evaluations of dental sealants through comparisons with faculty evaluations, and (2) determine if a difference in accuracy exists between dental and dental hygiene students. Dental (n = 17) and dental hygiene (n = 13) students from the University of North Carolina School of Dentistry at Chapel Hill placed and evaluated a total of 127 dental sealants on 29 patients in the undergraduate patient care system. Each student evaluated the placed sealant using criteria for the characteristics: area covered, quantity, porosity, and retention. The student self-evaluation was followed by an evaluation performed by two faculty examiners using the same criterion-referenced evaluation. The average of the two faculty evaluations was compared with the student's self-evaluation for analyses. Results indicated student scores were consistently higher than those given by the faculty. Additionally, dental and dental hygiene student scores correlated to about the same degree with the faculty average score.