Hohlraum Reheating from Burning NIF Implosions

As fusion experiments at the National Ignition Facility (NIF) approach and exceed breakeven, energy from the burning capsule is predicted to couple to the gold walls and reheat the hohlraum. On December 5, 2022, experiment N221204 exceeded target breakeven, historically achieving 3.15 MJ of fusion energy from 2.05 MJ of laser drive; for the first time, energy from the igniting capsule reheated the hohlraum beyond the peak laser-driven radiation temperature of 313 eV to a peak of 350 eV, in less than half a nanosecond. This reheating effect has now been unambiguously observed by the two independent Dante calorimeter systems across multiple experiments, and is shown to result from reheating of the remnant tungsten-doped ablator by the exploding core, which is heated by alpha deposition.

Increased Ion Temperature and Neutron Yield Observed in Magnetized Indirectly Driven D_{2}-Filled Capsule Implosions on the National Ignition Facility

The application of an external 26 Tesla axial magnetic field to a D_{2} gas-filled capsule indirectly driven on the National Ignition Facility is observed to increase the ion temperature by 40% and the neutron yield by a factor of 3.2 in a hot spot with areal density and temperature approaching what is required for fusion ignition [1]. The improvements are determined from energy spectral measurements of the 2.45 MeV neutrons from the D(d,n)^{3}He reaction, and the compressed central core B field is estimated to be ∼4.9  kT using the 14.1 MeV secondary neutrons from the D(T,n)^{4}He reactions. The experiments use a 30 kV pulsed-power system to deliver a ∼3  μs current pulse to a solenoidal coil wrapped around a novel high-electrical-resistivity AuTa_{4} hohlraum. Radiation magnetohydrodynamic simulations are consistent with the experiment.

Tumor necrosis factor-α and interleukin-6 concentrations in cerebrospinal fluid of dogs after seizures

BACKGROUND

Idiopathic and acquired epilepsy are common in dogs. Up to 30% of these dogs are refractory to pharmacological treatment. Accumulating experimental evidence indicates that brain immune response and presence of inflammatory mediators decrease the threshold for individual seizures and contribute to epileptogenesis.

HYPOTHESIS

Dogs with seizures have higher cerebrospinal interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) concentrations compared to dogs with no seizures.

METHODS

A prospective double blinded study; cerebrospinal fluid (CSF) and serum IL-6, TNF-α and total protein (TP) concentrations were measured by a blinded investigator for the study group and CSF IL-6 and TNF-α levels and TP concentrations were measured in the control group (CG).

ANIMALS

Dogs presented with seizures that had enough CSF collected to allow analysis were included in the study group. Twelve apparently healthy, quarantined, stray dogs served as control (CG).

RESULTS

Cerebrospinal fluid TNF-α and IL-6 concentrations were significantly higher (P = .011, P = .039) in dogs with seizures (0 ± 70.66, 0.65 ± 10.93 pg/mL) compared to the CG (0 ± 19, 0.73 ± 0.55 pg/mL). When assessing cytokine concentrations of specifically the idiopathic epilepsy (IE) dogs compared to the CG, only TNF-α concentrations (8.66 ± 62, 0 ± 19 pg/mL) were significantly higher (P = .01). CSF TP concentrations were not significantly higher in the study dogs compared to the CG.

CONCLUSIONS AND CLINICAL IMPORTANCE

Higher TNF-α and IL-6 concentration in the CSF of dogs with naturally occurring seizures. The higher supports the hypothesis that inflammatory processes through certain mediators play a role in the pathogenesis of seizures in dogs.

Acetylcholinesterase/C terminal binding protein interactions modify Ikaros functions, causing T lymphopenia

Hematological changes induced by various stress stimuli are accompanied by replacement of the primary acetylcholinesterase (AChE) 3' splice variant acetylcholinesterase-S (AChE-S) with the myelopoietic acetylcholinesterase-R (AChE-R) variant. To search for putative acetylcholinesterase-S interactions with hematopoietic pathways, we employed a yeast two-hybrid screen. The transcriptional co-repressor C-terminal binding protein (CtBP) was identified as a protein partner of the AChE-S C terminus. In erythroleukemic K562 cells, AChE-S displayed nuclear colocalization and physical interaction with CtBP. Furthermore, co-transfected AChE-S reduced the co-repressive effect of CtBP over the hematopoietic transcription factor, Ikaros. In transgenic mice, overexpressed human (h) AChE-S mRNA induced selective bone marrow upregulation of Ikaros while suppressing FOG, another transcriptional partner of CtBP. Transgenic bone marrow cells showed a correspondingly elevated potential for producing progenitor colonies, compared with controls, while peripheral blood showed increased erythrocyte counts as opposed to reduced platelets, granulocytes and T lymphocytes. AChE's 3' alternative splicing, and the corresponding changes in AChE-S/CtBP interactions, thus emerge as being actively involved in controlling hematopoiesis and the potential for modulating immune functions, supporting reports on malfunctioning immune reactions under impaired splice site selection.

Care for the Caregivers: a program for Canadian military chaplains after serving in NATO and United Nations peacekeeping missions in the 1990s

The Mental Health Department of the Canadian Forces Support Unit (Ottawa) developed the Care for the Caregivers program to help participants deal with stressful events experienced directly or vicariously from the NATO and United Nations military missions of the 1990s. The program was developed after complaints of postdeployment stress were received from various military care providers. The objectives were to improve the skills of support personnel and to reduce the distress that some caregivers experienced. Thirty-one chaplains who had been exposed to stressful military operations participated in five workshops. These educational 4-day small-group workshops covered topics such as post-traumatic stress disorder, vicarious traumatization, coping techniques, spirituality, self-care, and family issues. An adult education model was chosen to encourage dialogue. Outcomes included reports of professional and personal benefits, requests for additional programs, local education initiatives, and referrals to mental health professionals. Having met its objectives, the program has become a normal concluding part of stressful deployments.

Patient advocacy groups. A key prescription for dermatology

In addition to medical care, patient education and support is important to successful treatment of chronic dermatologic diseases. For assistance, dermatologists and patients should turn to patient advocacy groups, which provide educational materials, programs, support groups, and advocacy for patients with chronic skin diseases.

Spontaneous and nitrosourea-induced primary tumors of the central nervous system in Fischer 344 rats exposed to frequency-modulated microwave fields

In a 2-year bioassay, we exposed Fischer 344 rats to a frequency-modulated (FM) signal (836.55 MHz +/- 12.5 KHz deviation) simulating radiofrequency exposures in the head of users of hand-held mobile phones. We tested for effects on spontaneous tumorigenicity of central nervous system (CNS) tumors in the offspring of pregnant rats and also for modified incidence of primary CNS tumors in rats treated with a single dose of the neurocarcinogen ethylnitrosourea (ENU) in utero. ENU dosage (4 mg/kg) was selected to give an expected brain tumor incidence of 10-15% over the mean life span of 26 months. Pregnant dams (n = 102) were randomly assigned to six groups. Their offspring were treated as cohorts in each of the six groups (n = 90 per group; total, n = 540): Sham ENU/Sham Field, Sham ENU/Field Exposed, ENU/Sham Field, ENU/Field Exposed, ENU/Cage Control, and Sham ENU/Cage Control. Intermittent field exposures began on gestation day 19 and continued until weaning at 21 days, resuming thereafter at 31 days and continuing until experiment termination at 731-734 days. Energy absorption rates (SARs) in the rats' brains were similar to localized peak brain exposures of a phone user (female, 236 g, 1.0 W/kg; male, 450 g, 1.2 W/kg). Of the original 540 rats, 168 died before the termination of the experiment. In these rats, ENU significantly reduced survival from a mean of 708 days in three groups without ENU treatment to 645 days in three groups treated with ENU (P < 0.0005). There were no effects on survival attributable to FM field exposure in either ENU-treated or in sham-treated groups. Spontaneous CNS tumor incidence in control groups was 1.1-4.4% but sharply higher in rats receiving ENU (14.4-22.2%; P < 0.0001). No FM field-mediated changes were observed in number, incidence, or histological type of either spontaneous or ENU-induced brain tumors, nor were gender differences detected in tumor numbers. These negative findings with FM fields contrast with our study using standard digital phone fields pulsed on and off at 50/se, where a trend was noted toward reduced incidence of both spontaneous and ENU-induced CNS tumors (W. R. Adey et al., Radiat. Res., 152: 293-302, 1999). Although consistent but not attaining significance in the experiment overall (spontaneous CNS tumors, P < 0.08 one-tailed; P < 0.16 two-tailed; ENU-induced CNS tumors, P < 0.08 one-tailed, P < 0.16 two-tailed), the trend was significant (P < 0.015 one-tailed, P < 0.03, two-tailed) in rats that received ENU and died prior to experiment termination, with a primary brain tumor as the cause of death. We discuss differences in the signaling structure of digital and FM fields. Certain bioeffects induced by either amplitude-modulated or pulsed radiofrequency fields at athermal levels have not been seen with fields of similar average power but unvarying in intensity (continuous wave or frequency-modulated fields).

Pegaspargase-induced pancreatitis

BACKGROUND

The purpose of this study is to report the incidence of pancreatitis in patients treated with pegaspargase in our hospital during a 2-year period.

PROCEDURE

We identified episodes of pancreatitis related to the intramuscular administration of pegaspargase 2,500 IU/m(2) for the treatment of childhood hematological malignancies during a 2-year period (May 1996-April 1998). Patients were evaluated clinically and by sequential serum amylase and lipase determinations and radiographic examinations. For comparison, episodes of pancreatitis in patients who only received native Escherichia coli L-asparaginase were examined during the same time period.

RESULTS

Nine children with acute lymphoblastic leukemia (ALL) of 50 (18%) patients who received pegaspargase were diagnosed to have pancreatitis. All had prior therapy with native L-asparaginase. These children developed symptoms consisting of abdominal pain, nausea, vomiting, and decreased appetite within a median of 15 days from the onset of pegaspargase administration. Six patients became symptomatic after their initial dose. Seven patients developed severe or unacceptable toxicity (grades 3 and 4), measured by increased amylase (>2 times normal) and lipase levels or radiographic evidence of pancreatic inflammation or pseudocyst. One patient also developed hyperammonemia and encephalopathy. In contrast, only one out of 52 (1.9%) ALL patients who received native E. coli L-asparaginase during the same time period developed pancreatitis (P= 0.007).

CONCLUSION

Clinicians should be aware of a possible higher incidence of pancreatitis associated with pegaspargase.

Pure sylvian fissure arteriovenous malformations

OBJECT

Pure sylvian fissure arteriovenous malformations (AVMs) are vascular malformations confined to the sylvian fissure without parenchymal involvement. Because the branches of the middle cerebral artery are arteries of passage and the margins between the AVM and the insula cortex may be ill defined, many surgeons regard pure sylvian fissure AVMs as inoperable. The authors reviewed their surgical experience with eight patients harboring pure sylvian fissure AVMs to determine the incidence of operative morbidity.

METHODS

All eight patients experienced seizures, five (63%) had headaches, and three (38%) experienced hemorrhages. Preoperatively, six patients (75%) were normal neurologically and two (25%) had neurological deficits. Five (63%) of eight sylvian fissure AVMs were located in the dominant hemisphere. The size of the nidus ranged from 6 to 27 cm3 (mean 14 cm3). Complete removal of the AVM was documented by postoperative angiography in every case. Seizures were reduced or eliminated and headaches were relieved in all affected patients. Transient neurological deficits, which included aphasia, short-term memory loss, and hemiparesis, occurred in four patients (50%). Within 3 months, all patients were functioning independently with no new neurological deficits. The status of two patients who had had preoperative neurological deficits improved postoperatively. Neuropsychological testing showed no new cognitive deficits.

CONCLUSIONS

With appreciation for transient instances of postoperative morbidity, the outcome was excellent in all patients. The authors thus advocate microsurgery as the primary treatment for pure sylvian fissure AVMs.

Spontaneous and nitrosourea-induced primary tumors of the central nervous system in Fischer 344 rats chronically exposed to 836 MHz modulated microwaves

We have tested an 836.55 MHz field with North American Digital Cellular (NADC) modulation in a 2-year animal bioassay that included fetal exposure. In offspring of pregnant Fischer 344 rats, we tested both spontaneous tumorigenicity and the incidence of induced central nervous system (CNS) tumors after a single dose of the carcinogen ethylnitrosourea (ENU) in utero, followed by intermittent digital-phone field exposure for 24 months. Far-field exposures began on gestational day 19 and continued until weaning at age 21 days. Near-field exposures began at 35 days and continued for the next 22 months, 4 consecutive days weekly, 2 h/day. SAR levels simulated localized peak brain exposures of a cell phone user. Of the 236 original rats, 182 (77%) survived to the termination of the whole experiment and were sacrificed at age 709-712 days. The 54 rats (23%) that died during the study ("preterm rats") formed a separate group for some statistical analyses. There was no evidence of tumorigenic effects in the CNS from exposure to the TDMA field. However, some evidence of tumor-inhibiting effects of TDMA exposure was apparent. Overall, the TDMA field-exposed animals exhibited trends toward a reduced incidence of spontaneous CNS tumors (P < 0. 16, two-tailed) and ENU-induced CNS tumors (P < 0.16, two-tailed). In preterm rats, where primary neural tumors were determined to be the cause of death, fields decreased the incidence of ENU-induced tumors (P < 0.03, two-tailed). We discuss a possible approach to evaluating with greater certainty the possible inhibitory effects of TDMA-field exposure on tumorigenesis in the CNS.

Evaluation of some criteria used to select patients for brief psychodynamic therapy

BACKGROUND AND OBJECTIVES

The effectiveness of brief psychotherapy is established, but criteria for the selection of patients remain elusive. This study examines the usefulness of some widely used criteria for the selection of patients for brief psychodynamic therapy (BPT).

METHODS

A checklist of 39 criteria often used in a teaching hospital to screen patients for BPT was constructed. Scores derived from a principal components analysis of this checklist provided one set of predictor criteria. A second measure was derived from the consensual agreement of the independent ratings by 3 prominent advocates of BPT. A third predictor was derived from a similar analysis of items from the checklist on which consensual agreement for their relevance was obtained from the independent ratings of 23 BPT teachers in 16 university-affiliated hospitals. Reliable chart-based ratings of improvement in symptoms, increased insight, and improvement in general functioning of a convenience sample of 43 patients treated with BPT in the outpatient clinic of a teaching hospital served as outcome measures.

RESULTS

No correlation between any of the derived predictors and any of the measures of outcome was significant after a Bonferroni correction.

CONCLUSION

Teachers and clinicians still do not have good criteria for the selection of patients who will benefit from BPT. Exclusion of severe behavior disorders may, however, improve outcome rates by more than 15%.

Mouse-Torpedo chimeric alpha-subunit used to probe channel-gating determinants on the nicotinic acetylcholine receptor primary sequence

1. To determine if structural domains are important for nicotinic acetylcholine receptor (nAChr) channel function, six mouse-Torpedo chimeric alpha-subunits were constructed (Fig. 2) and coexpressed with Torpedo californica beta-, gamma-, and delta-subunits in Xenopus laevis oocytes. 2. nAChRs containing a chimeric alpha-subunit were examined by voltage- and patch-clamp methods to determine their functional characteristics. Dose-response curves from voltage-clamped oocytes were used to estimate EC50's and Hill coefficients. Whole-cell currents were normalized against the alpha-bungarotoxin (alpha-BTX) binding sites to obtain normalized responses to acetylcholine (ACh). Open time constants at 4 microM ACh were used to examine single-channel behavior. 3. The EC50 for ACh was modulated by the N-terminal half of the alpha-subunit. When the Torpedo subunit sequence between position 1 and position 268 was replaced by mouse sequence, the EC50 shifted toward the value for the wild-type mouse subunit. Replacement of either the 1-159 or the 160-268 positions of the Torpedo sequence with the mouse sequence lowered the EC50. This suggests that at least two regions play a role in determining the EC50. 4. When the primary sequence (160-268) of the Torpedo alpha-subunit was introduced in the mouse alpha-subunit (T160-268), the expressed chimeric receptor was nonfunctional. The inverse chimera (M160-268) was functional and the open time constant and EC50 were similar to those of mouse but the normalized response was characteristic of Torpedo. 5. The normalized macroscopic response to ACh (300 microM) of the chimera containing the mouse alpha-subunit showed a ninefold increase relative to the Torpedo wild type. Receptors which contain the C terminal of the mouse alpha-subunit also show an increase in the maximum normalized current. Receptors with the alpha-subunit which contain the Torpedo C-terminal sequence have a lower normalized response. 6. The combined results suggest that AChR channel function is modulated by structural determinants within the primary sequence. These structural domains might modulate channel function through specific allosteric interactions. The lack of response of the T160-268 chimera suggests that a critical interaction essential for the coupling of agonist binding and channel gating was disrupted. This result suggests that the interaction of structural domains within the nAChR primary structure are essential for channel function and that these intractions could be very specific within different nAChR species.

Factors related to quality of life and functional status in 50 patients with head and neck cancer

Quality of life (QOL) and functional status (FS) have become important outcome measures in cancer therapy. Valid and reliable instruments recently have been developed for examining QOL and FS in patients with head and neck (HN) cancer. The present study evaluated the relationships of QOL and FS to physical and psychological variables assumed to affect QOL and FS. Fifty patients were evaluated up to 6 years after HN cancer surgery using one general QOL instrument and three HN-specific instruments. Analysis of variance showed physical variables such as tumor site to be related to HN-specific scores, while psychosocial variables such as marital status were related to general QOL scores (P < or = .05). Several relationships were seen between physical or psychosocial variables and FS or QOL measures; however the relationships were not as strong or direct as expected.

Computed tomographic findings after acute carbon monoxide poisoning

Selective necrosis and degeneration of the globus pallidus are characteristic autopsy findings in patients with severe carbon monoxide (CO) poisoning. The objective of this study was to show that computed tomography (CT) may demonstrate these morphological changes in the brain during life, and provide a clue to prognosis. The authors reviewed the medical records of 19 consecutive patients with acute CO poisoning who underwent CT examination during hospitalization. Abnormal CT findings were found in 10 of the 19 patients (53%). The most common abnormal findings were low-density areas in the basal ganglia. These lesions were found in 7 of the 10 cases, and varied from small (limited to the globus pallidus) to large (extending to the internal capsule). Of the 10 patients with abnormal CT scans, 9 survived to hospital discharge but all had some degree of functional neurological impairment. Eighty-nine percent (8 of 9) of the patients with normal CT scans were discharged neurologically intact. Awareness of the potential for basal ganglia lesions in CO poisoning should lead to more accurate CT interpretation and may have significant prognostic implications.

Treatment of mandibular class III periodontal furcation defects. Coronally positioned flaps with and without expanded polytetrafluoroethylene membranes

Twenty-six mandibular class III furcation defects were treated in 26 subjects using a regenerative therapy that included citric acid root conditioning, placement of freeze-dried decalcified bone allograft and coronally positioned flaps secured by crown-attached sutures. In addition to this therapy, expanded polytetrafluoroethylene (ePTFE) membranes were placed in 14 of the 26 defects. The effect of these therapies was evaluated after 52 to 60 weeks through a series of soft and hard tissue probing measurements including residual furcation classification. For both treatments, mean improvements were observed for furcal probing attachment levels, furcal bone levels, and defect volumes. However, only a few of these through-and-through defects had become closed as judged by a panel of 3 independent examiners. Four defects in each of the 2 treatment groups had changed from Class III to Class I/II or Class II/II evaluated with the soft tissue in place. One defect treated without membrane and 3 defects treated with membranes had changed from Class III to Class II as recorded after reflection of the soft tissues at re-entry. Little difference was observed between defects treated with and without membranes. Further studies with larger sample sizes and longer observation times are needed to fully evaluate these regenerative procedures and their potential for healing Class III furcation defects.

Recurrent urinary conduit bleeding in a patient with portal hypertension: management with a transjugular intrahepatic portosystemic shunt

OBJECTIVE

To determine if a transjugular intrahepatic portosystemic shunt can control recurrent urinary conduit bleeding in a patient with portal hypertension.

METHODS

Following transjugular catheterization of the right hepatic vein, a long curve Colapinto needle was advanced through the liver parenchyma into the portal vein near its bifurcation. After a guide wire exchange, a catheter was advanced into the portal system and venogram was obtained. Following another guide wire exchange, a balloon angioplasty catheter was used to create the shunt by dilating the parenchymal tract between the hepatic and portal veins. A self-expandable stent was used to ensure patency of the shunt.

RESULTS

After shunt placement, bleeding from the ileal conduit and stroma decreased significantly. A duplex ultrasound at five-month follow-up demonstrated the shunt to be completely patent.

CONCLUSIONS

Based on this limited experience, it appears that the transjugular, intrahepatic, portosystemic shunt is an acceptable method to control massive, recurrent urinary conduit bleeding in patients with portal hypertension.

ATP sulfurylase from higher plants: kinetic and structural characterization of the chloroplast and cytosol enzymes from spinach leaf

Two forms of ATP sulfurylase were purified from spinach leaf. The major (chloroplast) form accounts for 85 to 90% of the total leaf activity (0.03 +/- 0.01 adenosine-5'-phosphosulfate (APS) synthesis units x gram fresh weight-1). Both enzyme forms appear to be tetramers composed of 49- to 50-kDa subunits with the minor (cytosolic) form being slightly larger than the chloroplast form. The specific activities (units x milligram protein-1) of the chloroplast form at pH 8.0, 30 degrees C, were as follows: APS synthesis, 16; molybdolysis, 229; ATP synthesis, 267; selenolysis, 4.1; fluorophosphate activation, 11. Kinetic constants for the physiological reaction were as follows: KmA = 0.046 mM, K(ia) = 0.85 mM, KmB = 0.25 mM, KmQ = 0.37 microM, K(iq) = 64-85 nM, and KmP = 10 microM, where A = MgATP, B = SO4(2-), P = total PPi at 5 mM Mg2+, and Q = APS. The kinetic constants for molybdolysis were similar to those of the APS synthesis reaction. The kinetic constants of the minor (cytosol) form were similar to those of the major form with two exceptions: (a) The molybdolysis activity was 120 units x milligram protein-1, yielding a Vmax (ATP synthesis)/Vmax (molybdolysis) ratio close to 2 (compared to about unity for the chloroplast form) and (b) KmA was greater (0.24 and 0.15 mM for APS synthesis and molybdolysis, respectively). Initial velocity measurements (made over an extended range of MgATP and SO4(2-) concentrations), product inhibition studies (by initial velocity methods and by reaction progress curve analyses), dead end inhibition studies (with monovalent and divalent oxyanions), and kcat/Km comparisons (for SO4(2-) and MoO4(2-) support a random AB-ordered PQ kinetic mechanism in which MgATP and SO4(2-) bind in a highly synergistic manner. Equilibrium binding studies indicated the presence of one APS site per subunit. HPLC elution profiles of chymotryptic and tryptic peptides were essentially the same for both enzyme forms. The N-terminal sequence of residues 5-20 of the cytosol enzyme was identical to residues 1-16 of the chloroplast enzyme.

Antimicrobial properties of human dentin impregnated with tetracycline HCl or chlorhexidine. An in vitro study

Substantivity of tetracycline HCl and chlorhexidine digluconate to human root dentin was assessed in vitro. 51 extracted single-rooted teeth, their crowns removed, were assigned to 1 of 4 treatments in groups of 12. A control groups included 3 roots. Each group was divided into 3 subgroups to allow evaluation of drug exposure for 1, 3 or 5 min. The roots were immersed in tetracycline HCl (10 or 50 mg/ml) or chlorhexidine digluconate (0.12 or 0.2%) solutions following root planning. Control roots were immersed in sterile saline (0.9%). Following drug immersion, the roots were transferred to tubes containing 2 ml tris buffered saline. The tubes were incubated at room temperature for 22 days. Desorption media were replaced at 24-h intervals. Removed media were examined for antimicrobial activity using a microtiter assay in which bacterial growth was evaluated by optical density readings. Roots immersed in tetracycline HCl 50 mg/ml released antimicrobial activity to successive desorption media for 14 days. Tetracycline HCl 10 mg/ml activity lasted 4 days. Roots subjected to chlorhexidine digluconate released antimicrobial activity for 24 h only. Within each treatment, there were no differences between the 3 exposure intervals of 1, 3 or 5 min. Our findings suggest usage of the periodontally exposed instrumented root as a depot for sustained release of tetracycline HCl, but not chlorhexidine digluconate, to the subgingival environment. The substantiveness of tetracycline HCl seems related to drug concentration rather than the exposure interval. Clinical trials are needed to confirm the clinical significance of these in vitro observations.

Retention of antimicrobial activity by human root surfaces after in situ subgingival irrigation with tetracycline HCl or chlorhexidine

Substantivity of tetracycline HCl and chlorhexidine digluconate was assessed in extracted teeth. Fifty periodontally compromised teeth scheduled for extraction with probing depths ranging between 6 and 12 mm were root planed and then irrigated in situ with 1 of 4 solutions: tetracycline HCl at concentrations of 10 or 50 mg/ml, 0.12% chlorhexidine digluconate, or 0.9% sterile saline. Each tooth was exposed to 150 ml of the respective irrigation solution. Following extractions, the teeth were transferred to tris buffered saline and incubated at room temperature for 22 days. Incubation solutions were replaced at 24-hour intervals. Removed solutions were examined for desorbed antimicrobial activity using a microtiter assay in which bacterial growth was evaluated by optical density readings. Tetracycline HCl 50 mg/ml exhibited significantly greater antimicrobial activity than chlorhexidine digluconate for 12 days and greater than saline for 16 days. Tetracycline HCl 10 mg/ml exhibited significantly greater antimicrobial activity than chlorhexidine digluconate and saline for 4 days. Chlorhexidine digluconate did not exhibit any significant antimicrobial activity at any time point. Our findings demonstrate long-lasting substantivity of tetracycline HCl, but not chlorhexidine digluconate, by teeth exposed to a single episode of pocket irrigation of their periodontally-exposed roots. The amount of antimicrobial activity retained is proportional to the concentration of tetracycline HCl used for irrigation.

Assessing Student Outcomes in a Nursing Learning Assistance Program

This study measured the apparent effectiveness of a Learning Assistance Program (LAP) in second-year baccalaureate nursing students using a process-outcome design. Seventy-eight students participated in LAP and 98 did not. SAT/ACT scores and freshman GPA were the cognitive "input" variables and the end-of-sophomore-year GPA the cognitive "outcome" variable. Affective variables at the beginning and end of the test year were the Study Attitudes and Methods Survey (SAMS) and the Survey of Reading and Study Efficiency (SR/SE). Statistical analysis included stepwise multiple regressions for evaluating the relationship between the process (LAP participation) and outcomes when the entry variables had been accounted for. Attending LAP improved participants' study attitudes and skills scores. There was a significant negative correlation between the degree of LAP participation by lower achieving students and their sophomore-year-ending GPA. This may be related to the fact that students who perform poorly on tests are encouraged to participate in LAP.

Isolation and continuous culture of Neorickettsia helminthoeca in a macrophage cell line

Experimental evidence is presented supporting the development of a system for the isolation and propagation of a Neorickettsia sp. in a continuous canine macrophage cell line (DH82). To isolate a Neorickettsia sp. pathogenic to the canine species, three naive dogs were fed metacercaria-encysted kidneys of salmon caught in a river where infection of metacercariae with Neorickettsia helminthoeca has been circumstantially known for decades. Clinically, the classic course of salmon poisoning disease developed in all of the dogs. Parasitemia began on day 8 to 11 postinfection, when the dogs developed a febrile peak, and continued until euthanasia. At necropsy, characteristic gross and microscopic lesions of the disease were present. A Neorickettsia sp. was also isolated from liver and spleen samples of these animals. The isolates have been continuously propagated and passed in DH82 cells for more than 6 months. Electron microscopic examination confirmed that the rickettsial organisms multiplied in the membrane-bound compartment of DH82 cells and that they morphologically closely resembled rickettsia belonging to the genus Ehrlichia. An indirect fluorescent antibody test using Neorickettsia organisms cultured in DH82 cells showed that all dogs seroconverted 13 to 15 days postinfection. Finally, inoculation of the cell-cultured Neorickettsia organisms into a naive dog reproduced clinically typical salmon poisoning disease which was of greater severity and had a more rapid time course than that in the dogs from which the original isolation was made. On the basis of the clinical and pathologic responses of the dogs in our study, we believe that virulent N. helminthoeca was isolated and cultured in a continuous cell line.

Periodontal repair in dogs: healing in experimentally created chronic periodontal defects

A need exists for well-defined animal models to objectively evaluate surgical principles and a possible role for biochemical wound conditioning and biomaterials in promoting periodontal regeneration. To test an existing model for its usefulness in quantitative evaluation of periodontal wound healing, large supraalveolar periodontal defects were surgically created around the mandibular premolars (P2, P3, P4) in left or right jaw quadrants in 5 beagle dogs. The defects were exposed to the oral environment for 6 months and were then subjected to reconstructive flap surgery (chronic defects). Healing in these defects was compared to healing following reconstructive surgery in similar contralateral defects which had not been exposed to plaque and calculus (acute defects). The animals were sacrificed after a 4-week healing period and tissue blocks including teeth and surrounding structures were processed for histometric analysis. Mean defect height (+/- s.d.) for chronic and acute defects amounted to 4.6 +/- 0.3 and 4.4 +/- 0.4 mm, respectively. Mean connective tissue repair to the root surface in chronic defects amounted to 62% (range 49% to 74%) of the defect height. Mean connective tissue repair in the acute defects exceeded 94% of the defect height in 4 of the dogs, but amounted to only 48% in 1 dog. Regeneration of alveolar bone and cementum was limited under both experimental conditions. Root resorption was frequently encountered, whereas ankylosis was seen in only few teeth. This study indicates that healing may vary not only as a result of controlled experimental variables, but also due to differences in biological response between dogs or to fortuitous traumatic factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Perforation of the colon due to endometriosis

Endometriosis is a common disease which affects the bowel in 12 to 35% of cases. Despite extensive serosal and intramural involvement, the intestinal mucosa usually remains intact and bowel perforation rarely occurs. We describe a patient with perforation of the sigmoid colon due to endometriosis. To our knowledge, this is the first such case to be reported in the radiologic literature.

CT diagnosis of perforated duodenal diverticulum

We present a case of perforated duodenal diverticulum diagnosed preoperatively on computed tomography. This rare but potentially fatal condition has been difficult to detect with more conventional radiographic techniques.

The duration of the sinus node depolarization on transvenous sinus node electrograms can identify sinus node dysfunction and can suggest its severity

Catheter recorded sinus node electrograms (SNE) allow visualization of sinus node depolarization (SND). The SND on a bipolar SNE is probably a composite reflecting both P cell action potentials and intranodal conduction. Reduced rate of rise, prolonged action potential duration and/or delayed intranodal conduction might each prolong the SND duration. Thus, SND duration might reflect several clinically important sinus node abnormalities and aid in the recognition of sick sinus syndrome. Moreover, the SND duration might be expected to be the most prolonged in patients with the most severe sinus node dysfunction. To test this hypothesis, we determined SND duration in 32 patients and correlated it with the presence or absence of evidence of sinus node dysfunction by ECG and/or electrophysiological (EP) studies. Seven patients had no sinus node dysfunction (group 1); 10 patients had mild sinus node dysfunction (a single abnormality of corrected sinus recovery time, sinoatrial conduction time, PCLp, or ECG) (group 2); and 15 patients had two or more abnormalities electrocardiographically and/or by EP testing (group 3). The SND duration (mean/range) was 129/95-190 msec in group 1, 151/95-225 msec in group 2, and 196/140-260 msec in group 3. In group 3, three patients who had ECG evidence of sick sinus syndrome and abnormalities on all three EP parameters, the SND duration was 230/200-260 msec. Carotid sinus massage (CSM) was found to prolong the SND duration in 5/7 patients in groups 2 and 3 where the SND could be measured both before and during CSM. CSM was necessary to allow visualization of the SND in 3/7 group 1 patients; thus their recorded values may be falsely long. The normal with a SND duration greater than 150 (190 msec) had it measured during CSM. None of the group three patients with SND duration less than msec had a prolonged CSRT or ECG evidence of sick sinus syndrome. Literature review revealed SNE recordings on 18 patients with sick sinus syndrome on which the SND duration could be measured; it was greater than or equal to 200 msec in all. Thus, the SND duration appears to reflect the presence and degree of sinus node dysfunction. Sinus node dysfunction appears unlikely if the SND duration is less than 150 msec and is likely to be severe if the SND duration is greater than 200 msec.

Computed tomography of condylar and articular disk positions within the temporomandibular joint

The computed tomograms of temporomandibular joints in 25 patients (41 joints) were retrospectively evaluated for condylar position and joint space with General Electric computer software. Computed tomography scans of the temporomandibular joint were made in the axial plane with the teeth in centric occlusion, and measurements were made from vertically reformatted images. Interarticular joint spaces were measured anterosuperiorly, superiorly, posterosuperiorly, and posteriorly from the condylar surfaces. This was repeated in five equidistant (3.1 mm) serial sagittal planes across the condyle, beginning and ending, on average, 2.5 mm from the lateral and medial condylar poles. Articular disk positions (anterolateral, anterior, anteromedial, medial, and normal) were correlated with condylar position. Significant differences between disk positions and joint spaces were found most frequently in the anterosuperior and the superior joint interval. When the disk was positioned normally, the anterosuperior joint space was consistent (1.5 to 2.0 mm) across the joint (standard deviation, 0.3 to 0.8 mm). The superior, the posterosuperior, and the posterior joint spaces in the normal joint were greater than the anterosuperior joint space. When the disk was anterior to the condyle, the anterosuperior joint interval was widened. When the disk was medial, the superior joint space was significantly wider than normal across the breadth of the condyle. In those joints in which the disk was anteromedial, there was an absence (0.2 mm) of joint space, and this occurred in all areas of the condyle except in its medial one fourth. In the internally deranged joint, joint space narrowing may be focal in nature.

Smoking behaviour of student nurses enrolled in diploma, associate degree and undergraduate nursing programmes

Because the literature shows that cigarette smoking is a major causative factor in the occurrence of chronic illness, lung cancer is becoming more common in women than breast cancer, nurses smoke more than any other group of health care providers and studies have not examined differences of smoking among the associate degree, undergraduate and diploma levels of nursing, this study was designed to examine selected health behaviours and their relationship to cigarette use among Alabama senior student nurses, and to determine smoking prevalence by level of educational preparation. A sample of senior associate degree, undergraduate and diploma student nurses in Alabama responded to an 87-item questionnaire which was personally administered by the investigator in a classroom setting. Twenty-two of the 87 items were used to compile the demographics, prevalences and health behaviours reported here. The remaining items were used to develop a sequence of information required to test Ajzen and Fishbein's Theory of Reasoned Action and are beyond the scope of this article. Though there was no significant difference of smoking prevalence among educational levels, there was a trend for increased smoking from undergraduate to diploma level with prevalences of: total sample, 26.2%; diploma, 30%; associate degree, 26%; and undergraduate, 24%. Health behaviours which were significantly different between smoking and non-smoking student nurses were breakfast frequency and coffee consumption. Having a regular exercise routine was not significant. Males smoked significantly more than females. More older nurses (over 40 years) smoked than younger nurses. The findings reported here are useful to the development of health education strategies designed to reduce and prevent cigarette use among student nurses.(ABSTRACT TRUNCATED AT 250 WORDS)

Food habits and preferences of Vietnamese children

In this study, information on food preferences and intake frequencies of 70 Vietnamese children was gathered by means of a questionnaire. The purpose was to compare the dietary habits of children who had been in the U.S. for more than one year with those of children arriving within the past year (1981). The results showed that children less than six years old who came to California more than one year ago consumed green leafy vegetables less frequently (p less than 0.01) and vitamin supplements more frequently (p less than 0.01) than those who came here recently. In the older groups (greater than 6 yrs), those who have been resident in the U.S. for more than one year consumed peanut butter and sweets (ice cream, pies, milkshakes) more frequently than those who had just arrived (p less than 0.001 and p less than 0.05, respectively). Older children (age greater than 6 yrs) who had been in the U.S. longer preferred American foods more than those who had just come (p less than 0.01). The majority of all children ate fruits as snacks. The consumption of rice, eggs, cheese, milk, meats and fruit juice was not significantly different in any of the four groups. This study also revealed a great need of nutrition education for the Vietnamese refugee mothers. Recommendations for planning nutrition education for this population are provided.

Prolongation of proton spin lattice relaxation times in regionally ischemic tissue from dog hearts

Proton NMR techniques were used to characterize acutely ischemic myocardial tissue from the dog. Ligation of the left anterior descending coronary artery for 30 min resulted in a consistent prolongation of the proton spin-lattice relaxation times (T1) in samples from regionally ischemic heart muscle when compared with T1 values for nonischemic areas from the same hearts. The relative prolongation of relaxation times in ischemic tissue was found to increase as the duration of ischemia was extended to 60 or 120 min. T1 values for ischemic tissue were not directly related to tissue levels of high-energy compounds, lactate, or hydrogen ions but largely reflected the increased water content of the regionally ischemic myocardium. Proton NMR analysis provides a means of identifying acute regional ischemia in heart tissue, and in the future may permit three-dimensional imaging of the heart in vivo.

Influence of prostaglandin precursors and synthesis inhibitors in vascular bed perfused without a pump

The present investigation was coducted to examine the role of endogenous prostaglandin (PG) on blood flow and arenergic responses in the paw vasculature perfused without a pump. The PG precursors, arachidonic acid and dihomo-gamma-linolenic acid, given i.a. caused only small increments in paw blood flow which were much less than that caused by PGE2 and PGE1. The i.a. administration of the PG synthesis inhibitors, indomethacin, meclofenamate and naproxen, caused a decrease in paw blood flow and increase in vascular resistance, whereas eicosa-5,8,11,14-tetraynoic acid had no significant effect. Vasoconstrictor responses evoked by norepinerphrine were unaffected after administration of indomethacin or eicosa-5,8,11,14-tetraynoic acid, whereas slight potentiation of the response to sympathetic nerve stimulation was obtained after indomethacin. These results suggest that in the cutaneous vascular bed of the paw, endogenous PG decreases the vascular resitance, but plays only a minor adrenergic modulating role, and then only on the response to adrenergic nerve stimulation.

Aneurysm of saphenous vein bypass graft to coronary artery

A few cases of aneurysmal dilatation of autogenous vein grafts to peripheral arteries have been reported. However, to our knowledge, no case of this complication in coronary artery vein bypass grafts have been found. We are presenting a case of a vein graft aneurysm which appeared 6 months postoperatively. The patient had had an aortic valve replacement and a vein bypass graft to the right coronary artery.