Whiplash causes increased laxity of cervical capsular ligament

BACKGROUND

Previous clinical studies have identified the cervical facet joint, including the capsular ligaments, as sources of pain in whiplash patients. The goal of this study was to determine whether whiplash caused increased capsular ligament laxity by applying quasi-static loading to whiplash-exposed and control capsular ligaments.

METHODS

A total of 66 capsular ligament specimens (C2/3 to C7/T1) were prepared from 12 cervical spines (6 whiplash-exposed and 6 control). The whiplash-exposed spines had been previously rear impacted at a maximum peak T1 horizontal acceleration of 8 g. Capsular ligaments were elongated at 1mm/s in increments of 0.05 mm until a tensile force of 5 N was achieved and subsequently returned to neutral position. Four pre-conditioning cycles were performed and data from the load phase of the fifth cycle were used for subsequent analyses. Ligament elongation was computed at tensile forces of 0, 0.25, 0.5, 0.75, 1.0, 2.5, and 5.0 N. Two factor, non-repeated measures ANOVA (P<0.05) was performed to determine significant differences in the average ligament elongation at tensile forces of 0 and 5 N between the whiplash-exposed and control groups and between spinal levels.

FINDINGS

Average elongation of the whiplash-exposed capsular ligaments was significantly greater than that of the control ligaments at tensile forces of 0 and 5 N. No significant differences between spinal levels were observed.

INTERPRETATION

Capsular ligament injuries, in the form of increased laxity, may be one component perpetuating chronic pain and clinical instability in whiplash patients.

Dynamic mechanical properties of intact human cervical spine ligaments

BACKGROUND CONTEXT

Most previous studies have investigated ligament mechanical properties at slow elongation rates of less than 25 mm/s.

PURPOSE

To determine the tensile mechanical properties, at a fast elongation rate, of intact human cervical anterior and posterior longitudinal, capsular, and interspinous and supraspinous ligaments, middle-third disc, and ligamentum flavum.

STUDY DESIGN/SETTING

In vitro biomechanical study.

METHODS

A total of 97 intact bone-ligament-bone specimens (C2-C3 to C7-T1) were prepared from six cervical spines (average age: 80.6 years, range, 71 to 92 years) and were elongated to complete rupture at an average (SD) peak rate of 723 (106) mm/s using a custom-built apparatus. Nonlinear force versus elongation curves were plotted and peak force, peak elongation, peak energy, and stiffness were statistically compared (p<.05) among ligaments. A mathematical model was developed to determine the quasi-static physiological ligament elongation.

RESULTS

Highest average peak force, up to 244.4 and 220.0 N in the ligamentum flavum and capsular ligament, respectively, were significantly greater than in the anterior longitudinal ligament and middle-third disc. Highest peak elongation reached 5.9 mm in the intraspinous and supraspinous ligaments, significantly greater than in the middle-third disc. Highest peak energy of 0.57 J was attained in the capsular ligament, significantly greater than in the anterior longitudinal ligament and middle-third disc. Average stiffness was generally greatest in the ligamentum flavum and least in the intraspinous and supraspinous ligaments. For all ligaments, peak elongation was greater than average physiological elongation computed using the mathematical model.

CONCLUSIONS

Comparison of the present results with previously reported data indicated that high-speed elongation may cause cervical ligaments to fail at a higher peak force and smaller peak elongation and they may be stiffer and absorb less energy, as compared with a slow elongation rate. These comparisons may be useful to clinicians for diagnosing cervical ligament injuries based upon the specific trauma.

Neck ligament strength is decreased following whiplash trauma

Background

Previous clinical studies have documented successful neck pain relief in whiplash patients using nerve block and radiofrequency ablation of facet joint afferents, including capsular ligament nerves. No previous study has documented injuries to the neck ligaments as determined by altered dynamic mechanical properties due to whiplash. The goal of the present study was to determine the dynamic mechanical properties of whiplash-exposed human cervical spine ligaments. Additionally, the present data were compared to previously reported control data. The ligaments included the anterior and posterior longitudinal, capsular, and interspinous and supraspinous ligaments, middle-third disc, and ligamentum flavum.

Methods

A total of 98 bone-ligament-bone specimens (C2–C3 to C7-T1) were prepared from six cervical spines following 3.5, 5, 6.5, and 8 g rear impacts and pre- and post-impact flexibility testing. The specimens were elongated to failure at a peak rate of 725 (SD 95) mm/s. Failure force, elongation, and energy absorbed, as well as stiffness were determined. The mechanical properties were statistically compared among ligaments, and to the control data (significance level: P < 0.05; trend: P < 0.1). The average physiological ligament elongation was determined using a mathematical model.

Results

For all whiplash-exposed ligaments, the average failure elongation exceeded the average physiological elongation. The highest average failure force of 204.6 N was observed in the ligamentum flavum, significantly greater than in middle-third disc and interspinous and supraspinous ligaments. The highest average failure elongation of 4.9 mm was observed in the interspinous and supraspinous ligaments, significantly greater than in the anterior longitudinal ligament, middle-third disc, and ligamentum flavum. The average energy absorbed ranged from 0.04 J by the middle-third disc to 0.44 J by the capsular ligament. The ligamentum flavum was the stiffest ligament, while the interspinous and supraspinous ligaments were most flexible. The whiplash-exposed ligaments had significantly lower (P = 0.036) failure force, 149.4 vs. 186.0 N, and a trend (P = 0.078) towards less energy absorption capacity, 308.6 vs. 397.0 J, as compared to the control data.

Conclusion

The present decreases in neck ligament strength due to whiplash provide support for the ligament-injury hypothesis of whiplash syndrome.

Effect of rotated head posture on dynamic vertebral artery elongation during simulated rear impact

BACKGROUND

Elongation-induced vertebral artery injury has been hypothesized to occur during non-physiological coupled axial rotation and extension of head. No studies have quantified dynamic vertebral artery elongation during head-turned rear impacts. Therefore, we evaluated effect of rotated head posture vs. forward head posture at the time of impact on dynamic vertebral artery elongation during simulated rear impacts.

METHODS

A whole cervical spine model with surrogate head and muscle force replication underwent either simulated head-turned (n = 6) or head-forward (n = 6) rear impacts of 3.5, 5, 6.5 and 8 g. Continuous dynamic vertebral artery elongation was recorded using custom transducer and compared to physiological values obtained during intact flexibility testing.

FINDINGS

Average (SD) peak dynamic vertebral artery elongation of up to 30.5 (2.6) mm during head-turned rear-impact significantly exceeded (P < 0.05) the physiological beginning at 5 g. Highest peak elongation of 5.8 (2.1) mm during head-forward rear impact did not exceed physiological limit. Head-turned rear impact caused earlier occurrence of average peak vertebral artery elongation, 84.5 (4.2) ms vs. 161.0 (43.8) ms, and higher average peak vertebral artery elongation rate, 1336.7 (74.5) mm/s vs. 211.5 (97.4) mm/s, as compared to head-forward rear impact.

INTERPRETATION

Elongation-induced vertebral artery injury is more likely to occur in those with rotated head posture at the time of rear impact, as compared to head-forward.

Multiplanar cervical spine injury due to head-turned rear impact

STUDY DESIGN

Head-turned whole cervical spine model was stabilized with muscle force replication and subjected to simulated rear impacts of increasing severity. Multiplanar flexibility testing evaluated any resulting injury.

OBJECTIVES

To identify and quantify cervical spine soft tissue injury and injury threshold acceleration for head-turned rear impact, and to compare these data with previously published head-forward rear and frontal impact results.

SUMMARY OF BACKGROUND DATA

Epidemiologically and clinically, head-turned rear impact is associated with increased injury severity and symptom duration, as compared to forward facing. To our knowledge, no biomechanical data exist to explain this finding.

METHODS

Six human cervical spine specimens (C0-T1) with head-turned and muscle force replication were rear impacted at 3.5, 5, 6.5, and 8 g, and flexibility tests were performed before and after each impact. Soft tissue injury was defined as a significant increase (P < 0.05) in intervertebral flexibility above baseline. Injury threshold was the lowest T1 horizontal peak acceleration that caused the injury.

RESULTS

The injury threshold acceleration was 5 g with injury occurring in extension or axial rotation at C3-C4 through C7-T1, excluding C6-C7. Following 8 g, 3-plane injury occurred in extension and axial rotation at C5-C6, while 2-plane injury occurred at C7-T1.

CONCLUSIONS

Head-turned rear impact caused significantly greater injury at C0-C1 and C5-C6, as compared to head-forward rear and frontal impacts, and resulted in multiplanar injuries at C5-C6 and C7-T1.

Frontal impact causes ligamentous cervical spine injury

STUDY DESIGN

Whole cervical spine model with muscle force replication was subjected to simulated frontal impacts of increasing severity, and resulting injuries were evaluated via flexibility testing.

OBJECTIVES

To identify and quantify cervical spine soft tissue injury and the injury threshold acceleration due to frontal impact.

SUMMARY OF BACKGROUND DATA

Cervical spine instability may result from automotive collisions. No previous studies have quantified soft tissue injuries due to frontal impact.

METHODS

Six human cervical specimens (occiput-T1) with muscle force replication were subjected to frontal impacts of 4, 6, 8, and 10 g. Before frontal impact, baseline flexibility data were collected following a 2 g simulation. Flexibility parameters of total (flexion plus extension) neutral zone (NZ), flexion NZ, total range of motion (ROM), and flexion ROM were obtained following each impact and compared with baseline flexibility. Injury was a significant increase (P < 0.05) in intervertebral flexibility due to frontal impact over baseline. Injury threshold was the lowest T1 peak acceleration that caused injury.

RESULTS

The injury threshold acceleration was 8 g, as determined by significant increases of 12.6 to 51.4% over the baseline flexibility, in the C4-C5 total NZ, and the C6-C7 total NZ, flexion NZ, total ROM, and flexion ROM. Following 10 g, significant increases in flexibility parameters were observed at C2-C3, C3-C4, C4-C5, C6-C7, and C7-T1.

CONCLUSIONS

Middle (C2-C3 to C4-C5) and lower (C6-C7 and C7-T1) cervical spine were at risk for injury during frontal impacts, for the experimental conditions studied.

Evaluation of the intervertebral neck injury criterion using simulated rear impacts

The Intervertebral Neck Injury Criterion (IV-NIC) is based on the hypothesis that intervertebral motion beyond the physiological limit may injure spinal soft tissues during whiplash, while the Neck Injury Criterion (NIC) hypothesizes that sudden changes in spinal fluid pressure may cause neural injury. Goals of the present study, using a biofidelic whole cervical spine model with muscle force replication, were to correlate IV-NIC with soft-tissue injury, determine the IV-NIC injury threshold, and compare IV-NIC and NIC. Using a bench-top apparatus, rear-impacts were simulated at 3.5, 5, 6.5, and 8 g horizontal accelerations of the T1 vertebra. Pre- and post-whiplash flexibility tests measured the soft tissue injury threshold, i.e. significant increases in the intervertebral neutral zone (NZ) or range of motion (ROM) above corresponding baseline values. Extension IV-NIC peaks correlated well with NZ and ROM increases at C0-C1 and at C3-C4 through C7-T1 (r=0.64 and 0.62 respectively, p<0.001). Average IV-NIC injury thresholds (95% confidence limits) varied among the intervertebral levels and ranged between 1.5 (1.1, 1.9) at C5-C6 and 3.4 (2.4, 4.4) at C7-T1. The NIC injury threshold was 8.7 (7.7, 9.7) m2/s2, substantially less than the proposed threshold of 15 m2/s2. Results support the use of IV-NIC for determining the cervical spine injury threshold and injury severity. Advantages of IV-NIC include the ability to predict the intervertebral level, mode, severity, and time of the cervical spine soft-tissue injury.

Cervical intervertebral disc injury during simulated frontal impact

Cervical disc injury due to frontal impact has been observed in both clinical and biomechanical investigations; however, there is a lack of data that elucidate the mechanisms of disc injury during these collisions. The goals of the current study were to determine the peak dynamic disc annular tissue strain and disc shear strain during simulated frontal impact of the whole human cervical spine model with muscle force replication at 4 g, 6 g, 8 g and 10 g horizontal accelerations of the T1 vertebra. These data were compared with those obtained during physiological loading, and with previously reported rear impact data. Peak disc shear strain and peak annular tissue strain during frontal impact exceeded (p<0.05) corresponding physiological limits at the C2-C3 intervertebral level, beginning at 4 g and 6 g, respectively. These subsequently spread throughout the entire cervical spine at 10 g, with the exception of C4-C5. The C5-C6 intervertebral level was at high risk for injury during both frontal and rear impacts, while during frontal impact, in addition to C5-C6, subfailure injuries were likely at superior intervertebral levels, including C2-C3. The disc injuries occurred at lower impact accelerations during rear impact as compared with frontal impact. The subfailure injuries of the cervical intervertebral disc that occur during frontal impact may lead to the chronic symptoms reported by patients, such as head and neck pain.

Nutrition, biochemistry, and tinnitus

Biochemical mechanisms are a significant factor in neurootological problems. Investigation of biochemical causes of neurootological problems, such as tinnitus, are warranted and can be cost-effective. Dietary, nutritional, chemical, hormonal, immunological, and stress factors are involved directly in neurootological problems and must be evaluated and considered in designing the treatment regimen for patients complaining of tinnitus.

[Neurohumoral mechanisms in pathophysiology of chronic heart failure]

Pathogenic mechanisms of chronic systolic heart failure are constantly of great interest. In recent years the neurohumoral theory of heart failure has gained attraction. According to this theory, neurohumoral mechanisms play the main role in the pathogenesis of heart failure, especially in its progression. These mechanisms can be divided into 2 categories: vasoconstrictive, mitogenic and antinatriuretic on the one hand and vasodilative, antimitogenic and natriuretic on the other one. The former consists of sympathetic nervous system, renin-angiotensin-aldosterone system, vasopressin, endothelin, cytokines. The latter comprises natriuretic peptides, prostaglandins and nitric oxide. Undoubtedly unfavourable roles of sympathetic system and renin-angiotensin-aldosteron have been shown in the progression of heart failure. Data are being also gathered confirming harmful effects of endothelin and cytokines and possibly of neuropeptide Y and vasopressine. Extensive data exist that demonstrate beneficial influence of natriuretic peptide on heart failure. The roles of nitric oxide as well as recently discovered adrenomedullin and medullipin are far from clear.

Inhibition of gastric secretion relieves diarrhea and postprandial urgency associated with irritable bowel syndrome or functional diarrhea

Five patients with gastroesophageal reflux disease (GERD), who also had chronic functional diarrhea and postprandial urgency, unexpectedly noted rapid relief of their diarrhea and urgency when they took lansoprazole for their heartburn. To determine if this surprising result was not fortuitous, all 20 patients seen during the next six months for chronic diarrhea and postprandial urgency due to irritable bowel syndrome (IBS) or functional diarrhea were treated with inhibitors of gastric secretion: 14 with proton-pump inhibitors and 6 with H2 blockers. All patients had rapid, marked improvement. Usually within three days, their symptoms abated and they usually had one to three formed stools per day. Relief continued during the one to six months they were followed on therapy. Five patients stopped therapy, had recurrent diarrhea, and rapid relief upon resuming therapy. Thus, inhibition of gastric secretion effectively controls the diarrhea and postprandial urgency associated with IBS or functional diarrhea, probably by diminishing the gastrocolic or gastroenteric reflex.

Pancreatitis. Evaluation and treatment

Acute and chronic pancreatitis present challenging problems for the physician. In acute pancreatitis, initial efforts should be directed toward supporting the patient hemodynamically. Recognition and early treatment of complications such as shock, renal failure, respiratory failure, hypocalcemia, abscess, hemorrhage, or unremitting symptoms caused by an impacted stone in the common bile duct are necessary. The cause of the pancreatitis must be identified, possibly for acute therapy, but certainly to prevent recurrences and progression of disease. In chronic pancreatitis, insufficiencies of pancreatic function must be identified and consequent malabsorption and diabetes treated appropriately. The major challenge is the relief of chronic pain. It is hoped that this can be accomplished medically, but in carefully selected cases, specific types of surgery may be required.

The infectious etiology of peptic ulcer disease. Diagnosis and implications for therapy

During the past decade, peptic ulcer disease has become recognized as multifactorial in etiology, with a major component thought to be infection of the gastric mucosa with a spiral-shaped bacterium known as Helicobacter pylori. This organism has been found to cause most cases of chronic gastritis and is clearly pathogenic in most cases of duodenal and gastric ulceration. Biologic characteristics, epidemiology, and methods of detection (invasive and noninvasive) of H. pylori are discussed from a clinical perspective. Finally, eradication of H. pylori infection is difficult because of bacterial resistance and patient noncompliance.

The effects of short-term lansoprazole therapy on Helicobacter pylori infection and antral gastritis in duodenal ulcer patients

BACKGROUND/AIMS

Lansoprazole is a new potent proton pump inhibitor that exhibits activity against Helicobacter pylori in vitro. This study endeavored to determine the effects of 4 wk of lansoprazole therapy upon H. pylori infection and antral gastritis in duodenal ulcer patients and to determine the relationship of the gastritis with Helicobacter infection and with ulcer activity.

METHODS

Satisfactory antral biopsies were obtained from 119 duodenal ulcer patients before and after 4 wk of therapy with lansoprazole, ranitidine, or placebo. Sections were scored blindly for degree of active and chronic inflammation and extent of H. pylori infection.

RESULTS

Four weeks of lansoprazole (30 mg daily) or ranitidine (300 mg daily) therapy produced a significant decrease in H. pylori infection. The reduction of H. pylori infection, but not ulcer healing per se, correlated with the decrease in active and chronic antral inflammation. Reduction of H. pylori infection, however, did not improve the good ulcer-healing rates already achieved at 4 wk by potent acid inhibition.

CONCLUSIONS

Lansoprazole exhibits activity against H. pylori in vivo. Short-term improvement in antral gastritis is affected by reduction of H. pylori infection but not by ulcer healing.

Atypical forms of inflammatory bowel disease

Atypical forms of IBD include the microscopic colitides, collagenous and lymphocytic colitis, and two macroscopic colitides, SRUS and diversion colitis. Clinical presentations include chronic, watery diarrhea and intermittant rectal bleeding. Constitutional symptoms are typically absent; laboratory data are often nonspecific. Colonoscopic evaluation and mucosal biopsy are essential in establishing these diagnoses and excluding more classic forms of IBD (i.e., Crohn's disease or idiopathic ulcerative colitis). Prognosis and response to treatment are variable; potential therapeutic options include dietary manipulations, topical or systemic anti-inflammatory agents, and, in refractory cases, surgical intervention.

Medical treatment of peptic ulcer disease

Our understanding of PUD and its treatment has improved dramatically during the past 15 years. During this time, many new effective drugs have been approved by the FDA, and possibly even more potent and effective therapies are now being evaluated. The H2-blockers, sucralfate, and antacids heal over 90% of duodenal ulcers in 6 to 8 weeks, and H2-blockers heal about 80% of gastric ulcers by 8 weeks and over 90% by 12 weeks. The new, more potent pump blockers (omeprazole) promise to be even more effective drugs, even for the healing of patients who are taking NSAIDS. However, the potential hazards of marked, long-term acid suppression must still be evaluated. Maintenance therapy with H2-blockers or sucralfate, ideally used for patients who would otherwise have frequent symptomatic recurrences of duodenal ulcer disease or who have had complications, reduces the relapses, especially symptomatic relapses. Maintenance therapy with H2-blockers also seems to reduce the recurrences of GUD, but this use has not yet received FDA approval. Elimination of H. pylori infection with antibiotics may prove to reduce recurrent ulcer disease and negate the need for maintenance therapy. Colloidal bismuth subcitrate alone, which suppresses but does not eradicate H. pylori infection, seems to be an effective ulcer drug and may even reduce the rate of early recurrences. Effective ulcer therapy, especially if it prevents recurrent disease, may reduce the complications of PUD, but this expectation has yet to be established. The use of prophylactic cytoprotective prostaglandins (misoprostol) reduces the incidence of NSAID-induced GUD.

The dizzy patient: etiologic treatment

The basis for the vestibular complaint in dizzy patients should be viewed as having an etiology rather than a description of its clinical presentation. Effective treatment of vestibular disorders is based on the stabilization of the vestibular abnormality, to allow for central vestibular compensation. While not all of the etiologies for dizziness have been described, there are effective etiologic treatments available. These fit into categories of neurotransmitters, blood sugar and blood fat control, hormones, minerals, and treatments for autoimmune dizziness.

Etiologic diagnosis in neurotologic disease

The inner ear is a converter (transducer) of mechanical to electrical energy for both hearing and balance functions. This task is accomplished as a result of the presence of the chemicals within the perilymph and endolymph. Maintaining normal hearing and balance function is dependent upon the availability of the proper chemicals to perform this transduction task. The inner ear functions as an internal body organ and its efficiency in regard to performing its tasks related to hearing and balance function are chemically dependent upon many body systems.

How do we use state of the art vestibular testing to diagnose and treat the dizzy patient? An overview of vestibular testing and balance system integration

The physician must be the captain of the vestibular diagnostic team based on his interest, knowledge, and capability. It is not the battery of vestibular or etiologic function tests used that provides diagnostic answers. It is the intelligent application and use of the indicated vestibular tests that are practically correlated and clinically evaluated that will give the knowledgeable physician significant information. This can best be accomplished when testing is done in physical proximity to the responsible physician and when the tests used are knowledgeably ordered and evaluated. Under such circumstances, vestibular function testing is always cost-effective and therapeutically useful.

Efficacy of alternative tests for delayed-cyclic food hypersensitivity

With the oral challenge food test (OCFT) used as the standard for delayed-cyclic food hypersensitivity diagnosis, blinded comparison studies were accomplished with 175 in vitro food specific IgE and 180 IgG radioallergosorbent tests, 180 food enzyme-linked immune complex assays, and 155 in vivo Multi-Test prick tests. The study was multi-centered, eight physicians and 37 patients participating. All of the compared tests were shown to be approximately 50% efficient when compared with the OCFT results, and, thus, nonefficacious.

Allergy and the immunologic aspects of otitis media with effusion

We reviewed the literature since 1980, and discovered that there is a distinct small subset of patients with otitis media with effusion (OME) in whom the middle ear acts as a shock organ for an IgE-mediated, type I allergic reaction. In the majority of patients, however, no direct relationship between the type I reaction and OME can be drawn. Both the type III and type IV reactions are strongly incriminated in the pathogenesis of OME. Much work remains to be done to clarify the exact role of the immune system in OME.

Site of lesion vestibular function testing

The results of conventional electronystagmography (ENG) sometimes are confusing. The Hallpike alternate binaural bithermal (ABB) caloric test is helpful diagnostically except for the group of "sick patients that have a normal test." Conventional ENG tests also fall short in the area of objective confirmation of patient progress. What does each test tell us regarding site of lesion? 1. Alternate binaural bithermal stimulation gives us information about the semicircular canals -- particularly the horizontal semicircular canal -- pickup head. 2. Simultaneous binaural bithermal stimulation gives information brain stem connections -- switching and relay. 3. Rotation testing gives information about the processing by the brain -- central control.

Identification of the APUD endocrine cells of rat fundic mucosa by means of combined amine fluorescence and electron microscopy

Rat fundic mucosa contains numerous APUD endocrine cells that can take up 5-hydroxytryptophan (5-HTP) and decarboxylate it to 5-hydroxytryptamine (serotonin), detectable by its formaldehyde-induced yellow fluorescence. To identify these cells by electron microscopy, pieces of rat gastric mucosa were incubated with DL-5-HTP. Some specimens were fixed in 4% formaldehyde-0.5% glutaraldehyde, while others were frozen, freeze-dried, and exposed to paraformaldehyde vapors. Thick sections of the Epon-embedded specimens were examined and photographed by fluorescence microscopy, and fluorescing and nonfluorescing cells were identified by electron microscopy in serial thin sections. Control specimens, not incubated with 5-HTP, revealed fluorescence of only the mast cells and EC cells, which were abundant in the pylorus, but rare in fundic mucosa. Specimens incubated with 5-HTP also exhibited numerous yellow fluorescent endocrine cells in fundic mucosa, which cells were found to be the ECL cells; the A-like cells did not fluoresce. In pyloric mucosa, many G and D (D1) cells also exhibited weak or moderate fluorescence after 5-HTP incubation. Thus, this study supports the contention of previous radioautographic studies that the ECL, but not the A-like, cells are the APUD endocrine cells of rat fundic mucosa, that G and D cells also possess some APUD activity, and that EC cells represent the enterochromaffin cells, which normally synthesize and store demonstrable quantities of serotonin.

Vestibular function testing: where are we in 1983?

Conceptual, technological, electronic and computer revolutions have transformed the methodology for evaluating the patient with dysequilibrium. What has been said and written for the past 25 years is not currently applicable. Present day, cost effective, clinical evaluation format is presented, including changes and deletions in the conventional ENG test battery. It also includes the addition of computer technology in the rotation and ocular tracking tests. These deletions and additions in technique provide the clinician with more useful practical data for diagnosis. There is also capability for patient follow-up and monitoring. These concepts are presented from the clinical vantage point and are supported with patient evaluation examples.

Harmonic acceleration as a measure of vestibular compensation

The results of conventional electronystagmography (ENG) sometimes are confusing. The Hallpike alternate binaural bithermal (ABB) caloric test is helpful diagnostically except for the group of "sick patients that have a normal test". Conventional ENG tests also fall short in the area of objective confirmation of patient progress. What does each test tell us regarding site of lesion? Alternate binaural bithermal stimulation gives us information about the semicircular canals--particularly the horizontal semicircular canal--pickup head. Simultaneous binaural bithermal stimulation gives information about brain stem connections--switching and relay. Rotation testing gives information about the processing by the brain--central control.

Harmonic acceleration tests as a measure of vestibular compensation

The material presented in excerpted from patient evaluations. The study was performed with the use of the Contraves rotary chair. This testing modality was used at each patient visit. All other conventional auditory and ENG tests were also performed. These patients have been selected to illustrate the value of the harmonic acceleration (HA) test as a modality for monitoring patient progress. The HA graphs produced were a result of the presence or absence of central vestibular compensation. The findings on these investigations further confirm that HA test provide an objective monitor for vestibular abnormality.

An electron microscopic radioautographic identification of the APUD endocrine cells in the rat gastric pyloric glands

The rat stomach was shown some years ago to contain numerous endocrine cells with APUD ability--cells that could take up the amino acids L-5-hydroxytryptophan (5-HTP) or L-dihydroxyphenylalanine (L-DOPA) and could decarboxylate them to their respective amines, 5-hydroxytryptamine (5-HT, serotonin) and dopamine, by means of the enzyme DOPA-decarboxylase. In a recent study, most of the APUD endocrine cells in the rat oxyntic mucosa were shown by electron microscopic radioautography to be the enterochromaffinlike cells, while the A-like cells were shown to lack APUD ability. To identify the APUD cells in the pyloric mucosa, pieces of rat pylorus were incubated in organ culture with 3H-5-HTP and were processed for light microscopic and electron microscopic radioautography. Additional specimens were incubated with 3H-5-HTP and carbidopa, an inhibitor of DOPA-decarboxylase, used to block the decarboxylation of 3H-5-HTP to 3H-5-HT, or with 3H-5-HT, used to determine where exogenous 3H-5-HT localizes in the pyloric mucosa. The 3H-5-HTP labeled all three types of endocrine cells identified within the pyloric glands--the G, enterochromaffin, and D cells. As this labeling was inhibited by carbidopa, and as exogenous 3H-5-HT labeled these cells only lightly, the labeling must have resulted from the uptake and intracellular conversion of the 3H-5-HTP of 3H-5-HT. Thus despite their morphologic differences, all rat pyloric endocrine cells possess APUD ability, a property shared by many, but not all, of the peptide- and amine-producing endocrine cells located throughout the body.

Staging Meniere's disease and reporting results in Meniere's disease: symposium panel discussion

At its recent spring meeting, the American Neurotologic Society devoted a portion of its program to a symposium on staging Meniere's disease and reporting results. One of the problems discussed, was which preoperative audiogram should be used for reporting results of any treatment. I think that it is very important that we, as otologists, try to look at Meniere's disease or any inner ear dysfunction in a more scientific way. Some of you may feel, on initial evaluation of this material, that it is too cumbersome to be practical in your daily clinical work. However, we feel we have put forth a reasonable staging system and method of reporting results that can be quite helpful once the simple routine of using them has become established. The vertigogram, for example, which is designed to be very simple and not require any sophisticated equipment, should be as easy to read as an audiogram. If we try to approach the vagaries of Meniere's disease or any inner ear dysfunction in a more scientific fashion, I am sure that in several years we will be in a much better position collectively to evaluate our results and to help our patients. This type of comprehensive staging system for all of the components in Meniere's disease or any inner ear dysfunction will enable us to objectify diagnoses and treatment results so that they can be easily compared. We have put forth some of the ideas and methods that we think will help us arrive at a consensus for reporting results. We encourage you to try some of the suggestions presented in this article and welcome your comments and ideas for improving this staging system and method for reporting results.

Sinusoidal harmonic acceleration test in clinical practice

The author's experience during the first year of use of the Sinusoidal Harmonic Acceleration test in clinical practice is presented. The advantages of this test both in the diagnostic and monitoring areas are illustrated with patient evaluation summaries. Further, use of this test on a daily basis in the office practice of neurotology will define its role in the evolution and follow-up of neurotologic problems.

Electron microscopic radioautographic identification of the ECL cell as the histamine-synthesizing endocrine cell in the rat stomach

Rat gastric oxyntic glands contain argyrophil "enterochromaffin-like" endocrine cells that synthesize and store histamine and also have APUD ability--they can take up exogenous L-5-hydroxytryptophan (5-HTP), can decarboxylate it to 5-hydroxytryptamine (5-HT, serotonin) by the enzyme DOPA-decarboxylase, and can store the amine. Previous cytochemical studies suggested that these cells correspond to both the ECL and A-like cells, the two predominant endocrine cells identified by electron microscopy (EM) in rat oxyntic glands. In a recent study, however, we demonstrated that the ECL but not the A-like cell exhibited APUD ability when rat gastric mucosa was incubated with H3-5-HTP and studied by EM radioautography. The purpose of the present study was to identify by EM radioautography the histamine-synthesizing endocrine cells in the rat stomach. Pieces of rat (male Sprague-Dawley) gastric mucosa were incubated in organ culture with L-H3-histidine (50 muCi, 1.8 x 10(-5) M) with and without inhibitors and were processed for LM and EM radioautography. H3-histidine labeled the ECL cells heavily but the A-like and other endocrine cells only lightly. The labeling of ECL cells was only modestly reduced by cycloheximide, an inhibitor of protein synthesis, whereas the labeling of A-like and other endocrine cells was almost abolished. In contrast, the labeling of ECL cells was markedly reduced by 4-bromo-3-hydroxybenzyloxyamine (NSD-1055), an inhibitor of histidine decarboxylase and DOPA decarboxylase, but was not appreciably affected by carbidopa, an inhibitor of only the DOPA decarboxylase. Incubations with H3-histamine (50 muCi, 0.9 x 10(-5) M) failed to label endocrine cells. Thus, this study demonstrates that the ECL but not the A-like cell is the histamine-synthesizing endocrine cell of the rat stomach.