Metabolic activity in rat visual system during exposure to high and low intensities of patterned and diffuse light

An examination of rat visual system activity, during exposure to either "pattern" (black and white stripes) or "diffuse" (eye covered by white mask) visual stimulation at high or low illumination intensities (1600 and 1 lux at cornea, respectively), was carried out using the 2-deoxyglucose (2-DG) autoradiographic technique. Pattern elevated 2-DG uptake in the dorsal and ventral lateral geniculate nuclei, in the lateral posterior nucleus, and in area 17, but was less effective at the high than at the low light intensity. Diffuse light also elevated 2-DC uptake in the thalamic nuclei but the increase was less impressive and the same at both intensities. Diffuse light at either high or low intensity had no effect on cortex. Like thalamus and cortex, pattern was a less effective stimulus for the colliculus at the high than at the low intensity, but, in contrast to thalamus and cortex, high intensity diffuse light suppressed 2-DG uptake in the colliculus to a level below that produced by darkness; low intensity diffuse light had no effect. These 2-DG findings are discussed in terms of how forebrain and midbrain divisions of the rat's rod-dominated visual system maintained their respective spatial processing and change-detecting functions over a considerable range of illumination intensity.

Molecular characterization of an apical early endosomal glycoprotein from developing rat intestinal epithelial cells

The apical endosomal compartment is thought to be involved in the sorting and selective transport of receptors and ligands across polarized epithelia. To learn about the protein components of this compartment, we have isolated and sequenced a cDNA that encodes a glycoprotein that is located in the apical endosomal tubules of developing rat intestinal epithelial cells. The deduced amino acid sequence predicts a protein of 1216 amino acids with a molecular mass of 133,769 Da. The deduced amino acid sequence together with amino-terminal amino acid sequencing indicate that there is a cleaved 21-amino acid signal sequence at the NH2-terminal portion of the molecule. There is a single hydrophobic region near the carboxyl terminus that has the characteristics of a membrane-spanning domain and a 36-amino acid cytoplasmic tail. We have found that the major form of this protein in intestinal epithelial cells has a molecular mass of 55-60 kDa, which is significantly smaller than the size predicted from the cDNA sequence, suggesting that the protein is synthesized as a large precursor and processed to the smaller form. The smaller form remains associated with the membrane, however, possibly through noncovalent association with the transmembrane portion of the molecule or with another membrane protein. The extracytoplasmic domain is cysteine-rich, with three cysteine-rich repeats that are similar to cysteine repeats present in several receptor proteins. However, there is no other significant similarity to other proteins in the GenBank. The cytoplasmic tail contains a possible internalization motif and several consensus motifs for serine/threonine kinases. Northern blot analysis suggests a single abundant message, and Southern blot analysis is consistent with a single gene and the absence of pseudogenes for this unique endosomal protein.

Epidural spinal cord stimulation in the management of spasms in spinal cord injury: a prospective study

Forty-eight spinal cord injury victims were implanted with an epidural spinal cord stimulation system to treat spasms that had not satisfactorily responded to medical therapy. All the patients were at least 6 months after the injury. The protocol included assessment by independent examiners preoperatively and at 3, 6, 12 and 24 months after the implant. Pre- and postoperative data collection included the frequency and severity of the spasms. Combining the frequency and intensity scores into a 'severity' score provided a more accurate clinical picture. No patient observed neurological deterioration following the surgical procedure or the neurostimulation treatment. A statistically significant reduction in the severity of the spasms was observed in the follow-up evaluations, with results that progressively increased in time. It is appears that spinal cord stimulation is an effective and safe alternative in the management of spasms in spinal cord injury victims. Its exact role in relation to intrathecal baclofen infusion and ablative procedures remains to be defined.

Effects of music on cardiovascular reactivity among surgeons

OBJECTIVE

To determine the effects of surgeon-selected and experimenter-selected music on performance and autonomic responses of surgeons during a standard laboratory psychological stressor.

DESIGN

Within-subjects laboratory experiment.

SETTING

Hospital psychophysiology laboratory.

PARTICIPANTS

A total of 50 male surgeons aged 31 to 61 years, who reported that they typically listen to music during surgery, volunteered for the study.

MAIN OUTCOME MEASUREMENTS

Cardiac responses, hemodynamic measures, electrodermal autonomic responses, task speed, and accuracy.

RESULTS

Autonomic reactivity for all physiological measures was significantly less in the surgeon-selected music condition than in the experimenter-selected music condition, which in turn was significantly less than in the no-music control condition. Likewise, speed and accuracy of task performance were significantly better in the surgeon-selected music condition than in the experimenter-selected music condition, which was also significantly better than the no-music control condition.

CONCLUSION

Surgeon-selected music was associated with reduced autonomic reactivity and improved performance of a stressful nonsurgical laboratory task in study participants.

cDNA sequence identity for the type I interferon receptor subunit from cell lines of widely differing responsiveness to interferon

Melanoma cell lines exhibit strikingly different sensitivity to the antiproliferative effects of interferon. cDNAs encoding the Type I interferon receptor subunit were amplified by polymerase chain reaction, using as template RNA isolated from three melanoma cell lines displaying greater than 100 fold range in their sensitivity to the antiproliferative effects of IFN-beta. Comparison of the cDNA sequences obtained with the published cDNA sequence from the highly interferon-sensitive lymphoid cell line Daudi revealed only one base change that leads to a conservative amino acid substitution. It is concluded that the cellular differences in responsiveness to interferon, of the melanoma cell lines tested, do not arise from the expression of variants of the cloned Type I interferon receptor subunit.

Psychometric assessment of the Allen Barriers to Treatment Instrument

The purpose of this study was to determine the psychometric properties of the Allen Barriers to Treatment Instrument (ABTI). Internal consistency reliability was assessed as well as five types of validity: face, content, criterion-related, convergent, and construct. A panel of experts was used to assess face and content validity of the ABTI; a two-group comparison method was used to evaluate criterion-related validity; qualitative analysis of responses to open-ended questions on the ABTI provided information about convergence; and item-to-total correlations of scores along with factor analysis was used to evaluate construct validity. Results showed strong evidence of the reliability and validity of the ABTI.

Development of an instrument to identify barriers to treatment for addicted women, from their perspective

This article reports the development of the Allen Barriers to Treatment Instrument, designed specifically for identifying barriers for women. An extensive search and review of the literature in the areas of barriers, access to care, and utilization of services was completed. Not only was a definition for "barriers" derived from this search, indicators for items used on the instrument were ascertained also. The article presents information on the rationale for developing the instrument the way it is and information on scoring.

Studies on the relationship between changes in radiographic bone height and probing attachment

The aim of this investigation was to determine the relationship between loss of radiographic crestal bone height and probing attachment loss. As part of this aim, we are introducing a new method for determination of a threshold for significant probing attachment loss which takes into account the error contributed by alteration in tissue tone. 57 adults with established periodontitis were selected. Radiographs were taken using the Rinn alignment system. Crestal change was determined from bone height measurements on digitized images of pairs of radiographs using the "side-by-side" technique of analysis developed recently by us. Probing attachment loss was measured using the Florida electronic probe system. Radiographic and probing measurements were made at baseline and after 1 year. No treatment was given during this period. A direct and significant relationship was observed between radiographic bone loss and probing attachment loss on a site basis (p = 0.0001, r2 = 0.018) and between subject means (p = 0.0014, r2 = 0.16). Radiographic and probing attachment change at all categories of sites, dichotomously classified as to not changing or loosing indicated 13% of sites were loosing by measurement of radiographic change and 9.6% were loosing by measurement of attachment change. Concordance in radiographic and attachment level change was found in 82% of sites examined. The relative diagnostic import of change in probing attachment or change in radiographic bone height requires treatment outcome studies based on use of diagnostic information of the 2 measuring techniques used singly and in combination.

Affective symptoms in the chronic stage of traumatic brain injury: a study of married couples

A convenient sample of 60 brain-injured subjects and their spouses was evaluated cross-sectionally in the chronic stage of recovery on self-rated measures of sensory, motor, cognitive and behavioural disability and on the SCL-90-R depression and anxiety subscales. A majority of the brain-injured subjects, who were on average almost 6 years post-injury, demonstrated elevations on the affective symptom scales, with almost 70% showing depression and 50% showing anxiety. The spouses of the brain-injured individuals also demonstrated significantly elevated affective symptom scales, with 73% acknowledging symptoms of depression and 55% demonstrating symptoms of anxiety. For the individuals with brain injury, those with higher self-ratings of cognitive disability and social aggression had higher self-ratings of depression and anxiety. In contrast, spouse gender appeared to have the greatest association with the presence of elevation affective responses, with female spouses having higher levels of depression and anxiety than male spouses. These findings are discussed in terms of the reactionary nature of affective disturbances in the chronic stage of recovery.

Applications of NMR spectroscopy to the study of experimental stroke in vivo

BACKGROUND AND PURPOSE

Magnetic resonance spectroscopy and imaging enable us to investigate biochemical and pathophysiological changes associated with cerebral ischemia. The specific aims of these studies were to establish the relationships between energy metabolites and regional cerebral blood flow and to determine whether diffusion-weighted imaging is sensitive to the known thresholds for cerebral tissue energy failure and disturbance of transmembrane ionic gradients in gerbils.

METHODS

Magnetic resonance spectroscopy measurements of energy metabolites in the gerbil brain were obtained as a function of cerebral blood flow (measured with the hydrogen clearance technique) before, during, and after unilateral or bilateral occlusion of the common carotid arteries. Diffusion-weighted and T2-weighted images were obtained in a separate series of experiments.

RESULTS

Major changes in brain energy metabolites were observed at flow values of 20 ml.100 g-1.min-1 and below. The cerebral blood flow threshold for maintenance of energy status was lowered in hypothermia, consistent with a protective effect. Diffusion-weighted imaging intensity increased at cerebral blood flow values of 15 to 20 ml.100 g-1.min-1 and below and increased gradually following the onset of severe global cerebral ischemia, but with a delay of about 2.5 minutes.

CONCLUSIONS

The spectroscopic observations suggest that the flow thresholds for electrical function and edema are a direct consequence of energy failure. Comparison of the spectroscopy and imaging data suggests that diffusion-weighted imaging is sensitive to disruption of tissue energy metabolism or to a consequence of this disruption. The possibilities arise of visualizing energy failure with the spatial resolution characteristic of magnetic resonance imaging and detecting compromised but recoverable tissue.

Attitudes of registered nurses toward alcoholic patients in a general hospital population

The Marcus Alcoholism Questionnaire was administered to 66 registered nurses at a community hospital to ascertain their attitudes regarding alcoholic patients in a general hospital population. This was done to provide documentation on what nurses attitudes actually are as opposed to making an assumption about what they should be because of the high visibility of the problem of alcoholism. The author reports the results of the study and then contrasts them with information about registered nurses attitudes toward alcoholic patients at a university hospital. The article concludes with insight into contributing factors for the differences.

Current morale issues that impede the caregiving process of substance abuse/addictions nurses

A telephone survey was conducted with 25 nurse managers of substance abuse/addictions programs in a metropolitan area to ascertain what morale issues impede the caregiving processes of their nursing staff. Five issues were repeatedly identified by all 25 nurse managers. Those issues were: (a) lack of credibility and respect for the nurse in the eyes of other members of the multidisciplinary team, (b) lack of understanding of the role of nurses in the substance abuse/addictions program on an inpatient unit; (c) lack of adequate preparation for the role, (d) lack of acceptance of the nursing role as defined by nursing, and (e) the care of patients with concurrent diagnoses. This article analyzes these issues from the perspective of reasons for existence and possible solutions.

The Effectiveness of Low Dose Slow Release Aspirin as an Antiplatelet Agent

An open, randomized, parallel group study of three different aspirin preparations was carried out. The objective of this study was to compare their ability to inhibit the production of thromboxane A2 (measured as thromboxane B2 [TXB2]) from platelets. Three aspirin preparations were studied: Acetard® 300 mg, Acetard® 100 mg and Platet® 100 mg. The study was conducted in 45 healthy adult volunteers and treatment continued once daily for 7 days. The results of the TXB2 assay show that the administration of all three treatment preparations produced a rapid drop in TXB2 levels of all volunteers. The baseline TXB2 level was reduced by 95% for all groups by day 3. Analysis by day showed a significant difference ( P<0.05) between treatments at day 1, with Acetard® 100 mg having higher TXB2 levels than the other two groups. Analysis of changes from baseline showed a significant reduction ( P<0.05) in TXB2 levels at Days 1 to 14 for all three groups. Platelet aggregation also showed a significant reduction, being reduced to 10% of control at 7 days. It then reverted back to baseline by 28 days for all treatment groups. In conclusion, low dose aspirin is very effective as an antiplatelet agent and in a slow release form loses none of its patency.

A novel device for the rapid in-clinic measurement of haemoglobin A1c

In order to evaluate a novel technique for measuring haemoglobin A1c using a cassette-based immunoassay method we have undertaken a laboratory evaluation using 48 patient samples and a separate within-clinic prospective study of 59 diabetic patients. Individuals were recruited from general (48 patients), paediatric (19 patients), obstetric (24 patients), and general practice (15 patients) diabetic clinics. Agreement was evaluated between HbA1c results obtained using the new method (AMES DCA 2000) and an established laboratory assay (DIAMAT HPLC system). The mean differences between the two results (AMES DCA 2000-DIAMAT) (95% confidence intervals) were: laboratory -0.69% (-1.42 to 0.04%); paediatric clinic -0.93% (-1.93 to 0.07%); obstetric clinic -0.29% (-1.09 to 0.51%), and general practice clinic -0.77% (-1.3 to -0.24%). For the AMES DCA 2000, the coefficient of variation for HbA1c of 5.2% was 1.6% and for HbA1c of 13%, 2.4%. This instrument was used without difficulty by four different operators. Intra-assay coefficient of variation for each operator was < 3.4%. In 9/18 patients where a specific assessment of clinical utility was made, knowledge of the HbA1c result at the time of consultation lead to a change in treatment. Methodology of this type may be used successfully within a diabetic clinic setting in both primary care and hospital environments.

The histopathology of infrainguinal vein graft stenoses

The precise histopathological nature of vein graft stenoses is unclear. Some authors have suggested that these lesions are due to intimal hyperplasia and others have claimed that they are fibrous strictures. The aim of this study was to determine the histological nature of infrainguinal vein graft stenoses by examining sections of vein grafts that had developed stenoses and had been surgically revised. This was performed using a combined anti-smooth muscle actin/Millers elastin stain. The results show that vein graft stenoses are due to intimal hyperplasia whereby smooth muscle cells proliferate and cause thickening of the intimal layer.

Social support in smoking cessation among black women in Chicago public housing

To accomplish significant reductions in smoking by the year 2000, special populations with relatively low rates of smoking cessation must be reached and helped to quit smoking. These populations are most often groups in which traditional approaches to smoking cessation have not been successful. Focus groups were conducted with black women who were residents of Chicago public housing developments. The purposes were to assess factors related to smoking and the women's willingness to participate in cessation programs. The findings reveal several barriers to smoking cessation. These barriers are linked to the difficult daily existence and environment of these women and to a lack of social support that would help them to achieve smoking cessation. The barriers include (a) managing their lives in highly stressful environments, (b) major isolation within these environments, (c) smoking as a pleasure attainable with very limited financial resources, (d) perceived minimal health risks of smoking, (e) commonality of smoking in their communities, (f) scarcity of information about the process of cessation available to them, and (g) belief that all they need is the determination to quit on their own. The women emphasized that smoking cessation would be more relevant to them if part of broader social support efforts geared to improve their lives. The public health system may need to consider such strategies to engage this group of women.

Analysis of bone X-rays using morphological fractals

The authors have applied mathematical morphology for fractal analysis on bone X-ray images. The digitized gray level image is treated as a three-dimensional surface whose fractal dimension is calculated by performing a series of dilations on this surface and plotting the area of the resulting set of surfaces against the size of the structuring element. This approach has the added advantage of encoding structural information via the use of a structuring element. The algorithm has been applied to several bone radiographs, and the results demonstrate that the fractal dimension using mathematical morphology gives a robust texture measure of trabecular bone structures.

Bonding amalgam to tooth structure: a scanning electron microscope study

The purpose of this scanning electron microscope study was to observe the interface between dentin and amalgam utilizing various adhesive resin cements. The adhesive resin materials used in this study were Imperva Dual, Geristore, and Panavia. The scanning electron micrographs revealed that bonds were established between amalgam, adhesive resins, and dentin.

Prostacyclin production from seeded prosthetic vascular grafts

Endothelial cell seeding has been proposed as a method of improving patency rates in small-calibre prosthetic vascular grafts. In vivo, endothelial cells normally produce prostacyclin (PGI2), a potent antiplatelet agent. The aim of this study was to determine whether seeded grafts show significant PGI2 production after in vivo implantation. Grafts were seeded with either autologous canine venous endothelial cells or autologous microvascular endothelial cells. After 12 weeks, PGI2 production was assessed under basal and stimulated conditions. Seeded grafts were compared with non-seeded controls and the corresponding aorta. The overall patency rate in seeded grafts was 80 per cent compared with 10 per cent in non-seeded grafts (P < 0.01). Grafts seeded with cells from either source produced significantly more PGI2 than unseeded grafts in both basal and stimulated states (P < 0.05). The aorta produced significantly more PGI2 than seeded grafts under both conditions (P < 0.01). Endothelial cell seeding produces a functional graft and leads to an improved patency rate.

Computerized methodology for detection of alveolar crestal bone loss from serial intraoral radiographs

The aim of this study was to develop a computerized measurement system for analysis of unstandardized serial radiographic images. A new approach for estimating the error associated with the determination of alveolar crest loss is described. The study shows that a difference of 0.87 mm in cemento-enamel junction-crest measurement between unstandardized serial radiographs taken within accepted clinic routine is required for a significant loss in crestal bone height. The ability to detect with significance a difference of less than 1 mm in crestal bone height makes the appropriate use of traditional bite-wing radiographs a useful diagnostic tool for the assessment of periodontal maintenance.

Disruption of pioneer growth cone guidance in vivo by removal of glycosyl-phosphatidylinositol-anchored cell surface proteins

Cell surface proteins anchored to membranes via covalently attached glycosyl-phosphatidylinositol (GPI) have been implicated in neuronal adhesion, promotion of neurite outgrowth and directed cell migration. Treatment of grasshopper embryos with bacterial phosphatidylinositol-specific phospholipase C (PI-PLC), an enzyme that cleaves the GPI anchor, often induced disruptions in the highly stereotyped migrations of peripheral pioneer growth cones and afferent neuron cell bodies. In distal limb regions of embryos treated with PI-PLC at early stages of pioneer axon outgrowth, growth cones lost their proximal orientation toward the central nervous system (CNS) and turned distally. Pioneer growth cones in treated limbs also failed to make a characteristic ventral turn along the trochanter-coxa (Tr-Cx) segment boundary, and instead continued to grow proximally across the boundary. Treatment at an earlier stage of development caused pre-axonogenesis Cx1 neurons to abandon their normal circumferential migration and reorient toward the CNS. None of these abnormal phenotypes were observed in limbs of untreated embryos or embryos exposed to other phospholipases that do not release GPI-anchored proteins. Incubation of embryos with PI-PLC effectively removed immunoreactivity for fasciclin I, a GPI-anchored protein expressed on a subset of neuronal surfaces. These results suggest that cell surface GPI-anchored proteins are involved in pioneer growth cone guidance and in pre-axonogenesis migration of neurons in the grasshopper limb bud in vivo.

Effect of x-ray angulation on radiographic periodontal ligament space width

The aim of this study was to set up a model for quantitating a change in radiographic PDL width on variation of x-ray angulation within anticipated clinical limits. Four incisor and 4 molar sites of 6 human skulls were radiographed at varying angulation. Horizontal angulation changes were made over a 12 degrees range, in 3 degrees increments. Vertical angulation change was in one 10 degrees increment. Baseline radiographs were taken with the x-ray beam perpendicular to a buccal tooth surface in a horizontal direction and perpendicular or 10 degrees off the perpendicular in a vertical direction. The radiographs were converted to digitized images and PDL width measurements made utilizing a mouse-driven computer program. The mean PDL width differences between all possible horizontal and vertical combinations (n = 45) were compared with the mean of those obtained from differences observed in PDL width measurements on replicate baseline radiographs. Mean PDL width differences for incisor locations were statistically different from the mean baseline PDL width difference; posterior PDL width difference showed no statistical variation from the mean baseline PDL width difference. For radiographs taken within the range expected under clinical conditions, a significant change in PDL width may be observed in incisor locations. Posterior sites may not exhibit this significant change due to the anatomy of the region which may reduce the clarity of the radiographic image.

Patterns of failure following combined modality therapy for esophageal cancer, 1984-1990

From 1984-1990, 143 patients with squamous cell or adenocarcinoma of the esophagus were enrolled in a Phase I/II study of neoadjuvant chemotherapy followed by concurrent chemotherapy plus radiotherapy with or without subsequent esophagectomy. Patients received one cycle of Cisplatin or Carboplatin plus Etoposide for squamous cell carcinoma, or Cisplatin or Carboplatin plus 5FU for adenocarcinoma, followed by two cycles of the same chemotherapy given concurrently with 44-46 Gy over 5 weeks. Operable patients then underwent esophagectomy. Inoperable patients and those with positive surgical margins received additional irradiation (16-18 Gy). Twelve percent of the surgical group received preoperative radiotherapy doses > or = 50 Gy. Seventy-two percent (103) had clinical Stage I-III tumors and 28% (40) were clinical Stage IV (1983 American Joint Committee on Cancer criteria). Only clinical Stage I-III patients were analyzed with respect to patterns of failure. Isolated local failure occurred in 19/103 (18%) of clinical Stage I-III patients. Both local and distant relapse occurred in 15/103 (15%), and distant metastases alone occurred in 25/103 (24%). The 3-year actuarial rates of local and distant failures were 45% and 60%, respectively. Among the clinical Stage I-III patients who underwent surgery (n = 58) versus those who did not (n = 45), the 3-year actuarial local and distant failure rates were 30% versus 60% and 45% versus 45%, respectively. Multivariate analysis was performed to identify significant predictors of local control. For all clinical Stage I-III patients, treatment with surgery (p = 0.001) and with three or more cycles of chemotherapy (p = 0.02) were significant predictors of improved local control. Patients who underwent surgery were significantly younger and had a better performance status than those who did not. The improvement in local control with surgery did not translate into better survival, likely on account of a high operative mortality rate in older patients and those receiving > or = 50 Gy preoperatively. We conclude that local control remains poor with concurrent chemotherapy + radiotherapy for esophageal cancer. The addition of surgery improved local control, but distant metastases remain a problem both in this group of patients as well as those treated without esophagectomy. Efforts to improve local control appear warranted, but it remains to be demonstrated that improved local control translates into improved survival in esophageal cancer because of a high rate of distant metastases in patients whose disease is controlled in the esophagus.

Establishing reliability of the Community Oriented Program Environment Scale on chemically-dependent black females

Research instruments are often used on samples without determining their reliability for that group of subjects. As a result, information is disseminated that really has no scientifically sound base. Thirty chemically-dependent Black females were chosen as subjects to determine reliability of the Community Oriented Program Environment Scale on this population. They were administered the instrument, and reliability was obtained using the Kuder-Richardson 20 internal consistency test. Findings showed low overall reliability and extremely low subscale reliability on this sample. It was concluded that this instrument would yield uninterpretable data in looking at attrition and treatment environment with this population.

What alveolar crest level on a bite-wing radiograph represents bone loss?

In advanced periodontal disease alveolar bone crestal loss is readily apparent on radiographs. However, in incipient disease there is a lack of consensus regarding what constitutes crestal bone loss on a radiograph. To properly assess crestal bone loss radiographically requires an appropriate base of reference indicative of the absence of destructive periodontal disease. In this study the radiographic CEJ-crest distance as a measure of crest height was determined for sites at which clinical attachment measurements indicate no attachment loss. From these measurements it is concluded that no crestal bone loss is consistent with a range of radiographic CEJ-crest distance between 0.4 and 1.9 mm (95% confidence limits) as evidenced on bite-wings.

Binding of anti-acetaldehyde IgG antibodies to hepatocytes with an acetaldehyde-phosphatidylethanolamine adduct on their surface

We have previously shown that antibodies raised against acetaldehyde adducts of protein cross-react with an acetaldehyde adduct of dioleoylphosphatidylethanolamine, N-ethyl-dioleoylphosphatidylethanolamine, when the latter is incorporated into hexagonal phase phospholipid micelles. In the present study we demonstrate that these same IgG antibodies cross-react with N-ethyl-dioleoylphosphatidylethanolamine when this adduct is incorporated into the surface of hepatocytes. Hapten-specific IgG antibodies were purified from the sera of rabbits sensitized to an albumin-acetaldehyde conjugate that had been reduced with sodium cyanoborohydride (N-ethyl-RSA). The N-ethyl-RSA was coupled to an Affi-Gel-10 column to affinity purify the IgG. Liposomes containing N-ethyl-dioleoylphosphatidylethanolamine were fused with isolated hepatocytes, the affinity purified primary IgG antibodies were added, then fluorescein-conjugated second antibodies were added, and antibody binding to hepatocytes was measured by flow cytometry. The fluorescence of these hepatocytes was significantly greater (p less than 0.01) than control hepatocytes prepared with (1) pre-immune primary IgG antibodies with fluorescein-conjugated second antibodies, (2) no primary antibody but with fluorescein-conjugated second antibodies, and (3) no fluorescein-conjugated second antibodies.

A prospective longitudinal study of observation versus surgical intervention in the management of necrotizing pancreatitis

Pancreatic necrosis is now recognized as a principal determinant of survival in acute pancreatitis. However, it is currently unknown how frequently pancreatic necrosis develops in acute pancreatitis, how often pancreatic necrosis becomes secondarily infected, and whether sterile pancreatic necrosis represents an indication for surgery or can be treated by conservative means. In 194 patients with unequivocal acute pancreatitis, pancreatic necrosis developed in 38 (20%), as documented by dynamic pancreatography, and was confirmed by histologic diagnosis at surgery in 28. All patients were prospectively treated by medical means. Patients with pancreatic necrosis who remained persistently febrile underwent fine needle aspiration for bacterial culture. Infected pancreatic necrosis was demonstrated in 27 of the 38 patients (71%) with pancreatic necrosis and was treated by open drainage, yielding a mortality rate of 15%. All 11 patients with demonstrated sterile pancreatic necrosis, including 6 with pulmonary and renal insufficiency, were successfully treated without surgery. Pancreatic necrosis occurs in approximately 20% of patients with acute pancreatitis and is necessary for the development of secondary pancreatic infection. However, pancreatic necrosis by itself, even when accompanied by organ failure, is not an absolute indication for surgery. A trial of medical treatment for all patients with sterile pancreatic necrosis is in order.

A model for dentinal caries progression by digital subtraction radiography

Extracted teeth with preexisting carious lesions were incubated in vitro at 37 degrees C in an artificial saliva buffer. Four teeth were exposed to buffer alone, four to buffer containing 5% glucose, and four to buffer containing 5% sucrose. Time-lapse radiographs were made of the carious lesions using an orienting device that fixed the position of the tooth, x-ray film, and x-ray tube collimator. The radiographs were analyzed over a period of 8 weeks using digital subtraction radiography. The subtracted images revealed that three of the four teeth incubated in saliva alone showed an increase in radiodensity (remineralization) at the depths of the lesion; one tooth showed no detectable change. Three of the four teeth incubated in the presence of 5% glucose showed increased radiolucency (demineralization); one showed no detectable change. The four teeth incubated in the presence of 5% sucrose exhibited results similar to those teeth incubated in 5% glucose.

Tissue plasminogen activator in the treatment of superior vena caval thrombosis associated with parenteral nutrition

Two patients, one of whom was pregnant, developed superior vena caval thrombosis while receiving central parenteral nutrition. They were successfully treated with recombinant tissue plasminogen activator (t-PA).

Violence in a community emergency room

Violence in both community and county hospitals in the USA is increasing. It caused significant physical, emotional and economic hardship to many emergency department employees. We describe an incident that caused significant injury to an innocent bystander in a quiet upper-class community emergency department and outline procedures that hospitals and emergency department employees can take to combat this violence. Policy, procedures, planning and methods must be available for appropriately trained and equipped police officers to respond to such incidents. The effects of such violent episodes on the emergency department staff are discussed. Methods to prevent such incidents are presented.

Dacryocystorhinostomy failure: association with nasolacrimal silicone intubation

A retrospective review of 242 consecutive dacryocystorhinostomies (DCRs) revealed no association between failure and either age, gender, or etiology of the nasolacrimal obstruction. However, silicone intubation of the nasolacrimal system was associated with a statistically significant increase in the failure rate of primary DCR. We postulate that silicone tubing by inciting granuloma formation in the nose and lacrimal fossa, predisposes to DCR failure. Routine use of silicone tubing in DCR should be avoided unless there is canalicular scarring, a large valve of Rosenmueller occluding the common canaliculus, or a small contracted or scarred lacrimal sac.

Role of activated oxygen species on the mutagenicity of benzo[a]pyrene

Different scavengers of active oxygen species (superoxide dismutase, catalase, mannitol and dimethylfuran) were tested in the Ames Salmonella assay to determine the role of the reactive oxygen species in the benzo[a]pyrene (B[a]P) mutagenesis process. Exogenously added superoxide dismutase or catalase at 10-100 micrograms ml-1 top agar, or 3-12 mM mannitol showed no effect on B[a]P mutagenicity in the presence of S9 mix. However, dimethylfuran (DMF), a singlet oxygen scavenger, inhibited in a dose-related manner the mutagenic response of B[a]P in the presence of the microsomal fraction. DMF at 3 and 6 mM inhibited the number of revertants by 69 and 93% for strain TA 100, and 76 and 78% for TA98, respectively. DMF at these levels was neither toxic nor mutagenic to the bacteria. The result indicates that singlet oxygen may play an important role in promoting B[a]P mutagenicity.

Effect of x-ray beam vertical angulation on radiographic alveolar crest level measurement

Utilizing intraoral radiographs of human skulls taken at known vertical angulation, we have demonstrated that expression of the crest level as a distance between cej and the crest is as accurate as a ratio of bone height to root length. The degree of inaccuracy of either of these measures is related to the magnitude of the angular deviation of the x-ray beam from 90 degrees. Angular deviation can be estimated from calculation of a cusp height score (ratio of lingual cusp height to buccal cusp height x 100). Based on the analysis of cusp height scores it was determined that the x-ray beam angulation for posterior bitewings ranged between 90 degrees and 80 degrees whereas for posterior periapicals the angulation range was between 90 degrees and 70 degrees. Therefore, it is recommended that, for longitudinal studies of bone height, measurements of the crest to cej distance, particularly in the region of the molars, be made utilizing bitewing radiographs. For the premolar and incisor regions, deviation of the vertical angulation of an x-ray of up to 20 degrees from a 90 degrees baseline resulted in little, if any, change in crest level by either one of the two measures used. An appendix is provided for the theoretical modeling of the types and magnitude of change in crest level observed for projection images of different anatomical configurations.

Acute cerebral ischaemia: concurrent changes in cerebral blood flow, energy metabolites, pH, and lactate measured with hydrogen clearance and 31P and 1H nuclear magnetic resonance spectroscopy. III. Changes following ischaemia

CBF has been measured with the hydrogen clearance technique in the two cerebral hemispheres of the gerbil under halothane anaesthesia. At the same time, intracellular pH and the concentrations of lactate and high-energy phosphates were measured in the brain using 1H and 31P nuclear magnetic resonance spectroscopy. Flow and metabolism have been followed during either a 15- or a 30-min ischaemic period (induced by bilateral carotid occlusion) and for up to 1 h of recovery. There was no significant difference between the flow characteristics of the two experimental groups. High-energy phosphate levels and pH returned to control within approximately 20 min of the end of the ischaemic period. Lactate clearance, following a 30-min occlusion, was slower than the recovery of pH. The concentration of free ADP, calculated from the creatine kinase equilibrium, was lower during the recovery phase than under control conditions.

Physostigmine enhances blood flow-metabolism ratio in neocortex

Inhibition of central nervous system cholinesterase with a single pulse of physostigmine induces a pronounced increase of blood flow in the neocortex, cingulate gyrus, claustrum, and amygdala. This phenomenon is not accompanied by an increase in energy metabolism and may help explain the effect of this drug on memory in normal humans and patients with Alzheimer's disease, as well as other conditions. In contrast, a parallel increase of blood flow and metabolism was observed in the superior colliculus, a component of the visual pathways. Prolonged administration of physostigmine lead to persistent vasodilatation in the neocortex, a lessening of this effect in cingulate gyrus, claustrum and amygdala, and an increase in primary olfactory cortex and hippocampus when compared with single pulse administration. Effects of physostigmine on glucose utilization remained essentially the same as with pulse administration.

Crestal alveolar bone change in patients with periodontitis as observed by subtraction radiography: an overview

Subtraction radiography is a highly sensitive and useful technique for detecting crestal alveolar bone changes in patients. Utilizing this technique, researchers have demonstrated that 9% of crestal sites lose bone over a six-month period in untreated subjects with periodontitis. On the order of 10-13% of crestal sites were found to lose bone three months post-periodontal therapy which included surgery. Non-surgical therapy resulted in 0.5-2% of crestal sites with bone loss. Subtraction requires radiographs which have closely approximating projection geometry. Presently available technology for taking standardized radiographs based on an occlusal stent system is adequate for obtaining interpretable subtraction images.

Human postnatal pulmonary arterial remodeling. Ultrastructural studies of smooth muscle cell and connective tissue maturation

A quantitative light and electron microscopic study of the elastic conducting, small muscular resistance arteries (accompanying or just proximal to the terminal bronchioli) and respiratory unit pulmonary arteries was carried out on the autopsy specimens of 12 children (newborn to 2 years) and three adults, who died without cardiopulmonary disease. Between birth and 1 month, in muscular and respiratory unit arteries, wall thickness decreased due to a reduction in mean smooth muscle cell diameter (p less than 0.01) and a reduction in overlap between adjacent cells. In the elastic arteries, the distance between adjacent elastic lamellae decreased as smooth muscle cell diameter decreased (p less than 0.01 for both). At birth, smooth muscle cells appeared immature, synthetic rather than contractile organelles predominating. Smooth muscle cell filament (thick, thin, and intermediate) volume density increased by 12 to 13% by 6 months in the small muscular arteries and by 2 years in the elastic arteries (p less than 0.001 for both). Surface and cytoplasmic dense bodies increased in a similar manner (p less than 0.001). The findings indicate a postnatal increase in contractile myofilament and surface dense bodies. The amount of connective tissue in the subendothelium and media increased between 1 month and adulthood, collagen finally predominating in small muscular arteries and elastin in the conducting arteries. Collagen fibrils showed regional differences in size within the media, between media and adventitia, and between different types of artery, and increased in size with age (p less than 0.001). Thus, the intrapulmonary arteries from hilum to precapillary bed adapted structurally to extrauterine life. It is suggested that the high fetal pulmonary vascular resistance is due to the shape and arrangement of smooth muscle cells within the vessel wall, rather than to an excessive contractility of each cell. After 1 month, remodeling occurred more slowly with growth, involving an increase in wall thickness, connective tissue deposition, and smooth muscle cell maturation.

Quantitative estimation of lactate in the brain by 1H NMR

1H NMR was used to detect lactate accumulation in the intact gerbil brain postmortem. The lactate concentration was estimated from the spectra by comparison to signals from N-acetylaspartate, creatine + phosphocreatine, and water. The effects of T2, phase modulation, and solvent suppression were taken into account. The estimated concentrations were compared to determinations performed on the same brains after extraction. The lactate concentration estimated from the intact brain spectra was between 70 and 90% of the values determined in vitro, on the extracts, depending on the concentration standard used. If N-acetylaspartate was used as the standard then the proportion of detected lactate (92%) was not significantly different from 100%.