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Biomedical subjects

J D Day

Publications and source records attributed to J D Day.

At least 37 records · Page 2Linked to original sources
PubMed1996

Vagus nerve stimulation activates central nervous system structures in epileptic patients during PET H2(15)O blood flow imaging.

OBJECTIVE: To determine the central areas of activation by vagal nerve stimulation (VNS) in epilepsy. VNS is a promising neurosurgical method for treating patients with partial and secondary generalized epilepsy. The anti-epileptic mechanism of action from VNS is not well understood. METHODS: We performed H2(15)O PET blood flow functional imaging on three patients with epilepsy in a vagal nerve stimulation study (E04 Protocol with Cyberonics). The three patients included two that had previous epilepsy surgery but continued to have frequent seizures. Seizure onset was frontal in two patients and bitemporal in the third patient. Twelve PET scans per subject were acquired every 10 minutes with a Siemens 953/A scanner. In 6 stimulus scans, VNS was activated for 60 seconds (2 mA, 30 Hz) commensurate with isotope injection. In 6 control scans no VNS was administered. No clinical seizures were present during any scan. Three way ANOVA with linear contrasts subject, task, repetition) of coregistered images identified significant treatment effects. RESULTS: The difference between PET with VNS and without revealed that left VNS activated right thalamus (P < 0.0006), right posterior temporal cortex (P < 0.0003), left putamen (P < 0.0002), and left inferior cerebellum (P < 0.0009). CONCLUSIONS: VNS causes activation of several central areas including contralateral thalamus. Localization to the thalamus suggests a possible mechanism to explain the therapeutic benefit, consistent with the role of the thalamus as a generator and modulator of cerebral activity.

Adult↗
PubMed1996

Neurological surgery at the University of Vienna.

ANTON VON EISELSBERG was the first to resect a cerebral tumor at the First Surgical Clinic at the General Hospital in Vienna in 1904. He successfully removed a cerebral glioma, the first of no fewer than 15,000 tumors operated on at that hospital to date. von Eiselsberg and his successors, Egon Ranzi and Leopold Schönbauer, as heads of the First Surgical Clinic, devoted themselves intensively to brain surgery, and neurosurgery developed to be an integral part of Viennese surgery. During the first decades, a prominent neurologist, Otto Marburg, and a world-famous anatomist, Julius Tandler, were members of the neurosurgical operating team. This approach changed in the 1950s, when the brain surgeons aimed at becoming independent of the basic sciences. The founding of an independent neurosurgical department at the University of Vienna in 1964 under Herbert Kraus also marked the beginning of the formation of specialized sections for pediatric and stereotactic neurosurgery. After 1968, the operating microscope was greatly emphasized. As of 1970, cerebral tumors and cerebrovascular lesions were treated microneurosurgically. Many operations were performed by surgeons who were experienced in neurosurgery. This again changed in 1978 under the new head of the department, Wolfgang Koos, who regarded the neurosciences as the basis for neurosurgical training as well as neurosurgical activity. The reorganization of the neurosurgical institution coincided with the construction of a large modern building with state-of-the-art equipment for microneurosurgery, radiosurgery (gamma knife), neurodiagnostics, laboratories, etc. Many details of the construction plans, the equipment, and the organization of the department have their roots in the years that the present head of the department spent in the United States; this is also the reason for the close connection and cooperation of Vienna neurosurgery with many neurosurgeons in the United States.

Austria↗
PubMed1996

Surface and superficial surgical anatomy of the posterolateral cranial base: significance for surgical planning and approach.

We have performed an anatomic study, 15 using fixed cadaveric preparations, with the goal of identifying surface landmarks that will reliably locate the underlying transverse and sigmoid sinus complex. Simple morphometric relationships were first determined on both sides of each specimen to yield 30 sides measured. The following relationships were determined: 1) zygoma root-asterion, 2) asterion-mastoid tip, 3) zygoma root-suprameatal spine (Henle's spine), 4) asterion-suprameatal spine, 5) mastoid tip-suprameatal spine. The relationship of the asterion to the transverse-sigmoid junction was determined by bone removal. Also, the distances from the asterion to the sigmoid sinus-superior petrosal sinus junction and the superior margin of the transverse sinus were studied. Surface and marks were found to have definitive relationships to underlying anatomic substrates in all specimens studied. The critical relationships that were concluded from this study can be described in terms of two easily identified lines between bony surface structures. A line drawn from the zygoma root to the inion, i.e., the superior nuchal line, reliably located the rostrocaudal level of the transverse sinus in all specimens. Although the asterion did not consistently fall on this line, the transverse-sigmoid junction could reliably be placed at the anteroposterior level of the asterion. Further, a line drawn from the squamosal-parietomastoid suture junction to the mastoid tip reliably defined the axis of the sigmoid sinus through the mastoid. We also found that the junction of the squamosal and parietomastoid sutures lay over the anterior border of the upper curve of the sigmoid sinus. The anterior portion of the supramastoid crest correlated with the level of the middle fossa. These surface relationships all have significance for posterolateral approaches to the cranial base. Since performing this study, these relationships have been found reliable for operative planning in our clinical cases.

Cephalometry↗
PubMed1996

Innovations in surgical approach: lateral cranial base approaches.

The extradural anterior transpetrosal approach possesses several advantages. First, the majority of the dissection is extradural, providing protection to the overlying neural structures. Second, only limited retraction of the temporal lobe is necessary, protecting venous outflow via the vein of Labbe'. Third, transposition of cranial nerves or vascular structures in unnecessary. Fourth, it enjoys natural compatibility with other surgical approaches to enhance exposure of the posterior cavernous sinus and petroclival region. The disadvantages are mostly related to the unfamiliar anatomy. Most surgeons are not accustomed to visualizing petrous apical anatomy from the middle fossa orientation. Therefore, practice of this technique in the cadaver laboratory is a mandatory prerequisite to its performance in the operating room. The cochlea, carotid artery, labyrinth, and cranial nerves five through eight are all at risk during drilling and dissection. When performed properly, this technique provides a solid adjunct to treating complex lesions of the central cranial base.

Cavernous Sinus↗
PubMed1995

Endoscopically assisted microneurosurgery.

Technological developments in neuroendoscopy are leading to an expansion of applications into the realm of microneurosurgical procedures. The new dimension that using an endoscope provides requires insight into different neuroanatomical aspects and a new kind of strategy in planning a microneurosurgical procedure. To gain some new insights into these exciting aspects of neurosurgery we have explored the sellar, parasellar, and posterior fossa regions in 50 fresh anatomical specimens and used various types of endoscopes to observe the surgically relevant neurotopographical details. We then utilized this experience in 33 clinical cases during microsurgical approaches for various lesions (posterior fossa tumors - 12 cases, sellar and parasellar tumors - 8 cases, trans-sphenoidal procedures for pituitary adenoma - 7 cases, transventricular procedures - 6 cases). In the laboratory we found that familiar neuroanatomical structures are seen in a completely different aspect from what we are accustomed. Orientation is at times difficult, which requires rehearsal and special handling of the endoscope for complex clinical procedures. We found that certain structures that are hardly noticed in routine anatomical views become very important when utilizing the endoscope (i.e., different arachnoid membranes and trabeculae). Importantly, the dimensions of a microsurgical approach can be greatly enlarged with the endoscope, making it possible to look behind structures and ''around corners''. We present our findings with respect to important anatomical details relevant to utilizing the endoscope as an adjunct to microneurosurgical procedures and our clinical data. We have concluded that the neuroendoscope can be a safe and helpful adjunct in many microneurosurgical procedures.

Endoscopy↗
PubMed1995

The transfacet pedicle-sparing approach for thoracic disc removal: cadaveric morphometric analysis and preliminary clinical experience.

A number of operative techniques have been described for the treatment of herniated thoracic discs. The transfacet pedicle-sparing approach allows for complete disc removal with limited spinal column disruption and soft-tissue dissection. Fifteen cadaveric spinal columns were used for evaluation of exposure, development of thoracic microdiscectomy instrumentation, and establishment of morphometric measurements. This approach was used to remove eight thoracic discs in six patients. Levels of herniation ranged from T-7 through T-11. Preoperatively, all patients had moderate to severe axial pain, and three (50%) of the six had radicular pain. Myelopathy was present in four (67%) of the six patients. Through a 4-cm opening, the ipsilateral paraspinal muscles were reflected, and a partial facetectomy was performed. The disc was then removed using specially designed microscopic instrumentation. Postoperatively, the radiculopathy resolved in all patients. Axial pain and myelopathy were completely resolved or significantly improved in all patients. The minimal amount of bone resection and muscle dissection involved in the operation allows for: 1) decreased operative time and blood loss; 2) diminished perioperative pain; 3) shorter hospitalization time and faster return to premorbid activity; 4) avoidance of closed chest tube drainage; and 5) preservation of the integrity of the facet-pedicle complex, with potential for improvement in outcome related to axial pain. This technique appears best suited for the removal of all centrolateral discs, although it has been used successfully for treating a disc occupying nearly the entire ventral canal. The initial experience suggests that this approach may be used to safely remove appropriately selected thoracic disc herniations with good results.

Adult↗
PubMed1995

Intimate association of eosinophils to collagen bundles in eosinophilic myocarditis and ranitidine-induced hypersensitivity myocarditis.

BACKGROUND: Eosinophilic myocarditis is an inflammatory condition of the heart in which the infiltrate is composed predominately of eosinophils. DESIGN: We identified three cases of eosinophilic myocarditis in which the infiltrating eosinophils showed a remarkable intimate association with bundles of collagen. Two of the hearts examined were explants from heart transplant recipients with hypersensitivity myocarditis at the time of transplant and the third was from an autopsied patient with Churg-Strauss syndrome. These hearts were examined using light and electron microscopy. The cellular infiltrate in all three cases was characterized using immunoperoxidase stains with a panel including antibodies against myeloperoxidase, common leukocyte antigen (CD45), B lymphocytes (CD20), T lymphocytes (CD3), active-memory T lymphocytes (CD45RO), inactive T lymphocytes (CD45RA), and macrophages (CD68). RESULTS: Ultrastructural examination in all three cases confirmed the apposition of eosinophils to both large bundles of collagen and smaller aggregates of collagen fibrils. The eosinophils and the bundles of collagen stained strongly for myeloperoxidase, suggesting at least partial degranulation of the eosinophils. A KP-1 stain (CD68) revealed macrophages admixed with the eosinophils adjacent to the collagen bundles, and stains for CD45RA (naive lymphocytes) and CD45RO (memory T cells) showed an interstitial infiltrate of predominantly CD45RO-positive cells. Clinically, the cardiac decompensation of one of the transplant patients was most likely due to ranitidine-induced hypersensitivity myocarditis. CONCLUSIONS: These results suggest that some cases of eosinophilic myocarditis may be caused by the expression of novel antigens bound to collagen bundles. In one of the patients awaiting cardiac transplant, cardiac decompensation was temporally associated with ranitidine therapy, an agent not previously implicated as a cause of hypersensitivity myocarditis.

Adult↗
PubMed1995

Twin pregnancy diagnosis in Holstein cows: discriminatory powers and accuracy of diagnosis by transrectal palpation and outcome of twin pregnancies.

The objective of this prospective cohort study was to determine the sensitivity, specificity, accuracy, and predictive value of twin pregnancy diagnosis by rectal palpation and to examine fetal survival, culling rates, and gestational lengths of cows diagnosed with twins. In this prospective study, 5309 cows on 14 farms in California were followed from pregnancy diagnosis to subsequent abortion or calving. The average sensitivity, specificity, accuracy, and predictive value of twin pregnancy diagnosis were 49.3%, 99.4%, 96.0%, and 86.1%, respectively. The abortion rate for single pregnancies of 12.0% differed significantly from those for bicornual twin pregnancies and unicornual twin pregnancies of 26.2% and 32.4%, respectively (P < 0.05). The early calf mortality between cows calving with singles (3.2%) and twins (15.7%) were significantly different (P < 0.005). The difference in fetal survival between single pregnancies and all twin pregnancies resulted in 0.42 and 0.29 viable heifers per pregnancy, respectively. The average gestation for single, bicornual, and unicornual pregnancies that did not abort before drying-off was 278, 272, and 270 days, respectively. Results of this study show that there is an increased fetal wastage associated with twin pregnancies and suggest a need for further research exploring management strategies for cows carrying twins.

Abortion, Veterinary↗
PubMed1995

The management of penetrating vascular injuries.

Vascular disruption secondary to penetrating head trauma is most commonly in the form of surgically treatable intracranial and intracerebral hemorrhage. This article discusses the management of major cerbrobascular lesions associated with penetrating injuries to the neck and cranial vault, excluding traumatic aneurysms.

Arteriovenous Fistula↗
PubMed1994

Microsurgical anatomy of the inner surface of the petrous bone: neuroradiological and morphometric analysis as an adjunct to the retrosigmoid transmeatal approach.

The retrosigmoid transmeatal technique remains the approach of choice for hearing preservation during the removal of acoustic neuromas that protrude from the porus acusticus. However, encroachment into the bony labyrinth in an effort to remove the tumor in the lateral end of the internal auditory canal (IAC) continues to compromise hearing in certain cases. The limits in the safe removal of the posterior wall of the IAC are not generally agreed on. To address this problem, we have performed a morphometric analysis of 32 fixed cadaveric temporal bones by microsurgical dissection and measurement with fine-cut bone window computed tomographic (CT) scans. The morphometric relationships of identifiable surface landmarks were first determined. Fine cut bone window CT scans were next performed on each bone and the distances between the fundus, the vestibule, and the common crus (CC) with the internal auditory meatus (IAM) were determined. Additionally, the thickness of the bone overlying the posterior semicircular canal at the CC was measured. From a retrosigmoid trajectory, employing a 4-cm craniotomy, the posterior wall of the IAC was removed with a high-speed drill, limiting removal to the distance from the vestibule to the IAM, as determined by CT measurement. Preservation of the integrity of deep structures was confirmed by inspection. The length of the actual IAC unroofed was measured and was compared with the IAC length, from IAM to fundus, measured by CT. The average canal length by CT measured 10.0 mm +/- 1.8 (range, 6.6-14.0). The length of the canal uncovered averaged 5.9 mm +/- 1.4 (4.0-8.5).(ABSTRACT TRUNCATED AT 250 WORDS)

Cephalometry↗
PubMed1994

Microanatomical study of the extradural middle fossa approach to the petroclival and posterior cavernous sinus region: description of the rhomboid construct.

The extradural middle fossa transpetrosal approach has been used to access lesions of the petroclival and posterior cavernous sinus regions by several neurosurgical groups, including our own. This is a technically demanding approach that provides a relatively wide extradural corridor interposed between the 5th cranial nerve and the cranial nerve VII-VIII complex, which minimizes brain retraction. We performed a microanatomical study to determine the limits of this exposure and in particular how the removal of the petrous bone could be maximized through this approach. Dissection of 15 fixed human cadaveric heads and 8 isolated temporal bones was performed to yield 38 sides studied. We identified a rhomboid-shaped construct of middle fossa landmarks that serve as a guide to maximally removing the petrous apex. The points defining this construct are as follows: 1) the junction of the greater superficial petrosal nerve and the trigeminal nerve; 2) the lateral edge of the porus trigeminus; 3) the intersection of the petrous ridge and arcuate eminence; and 4) the intersection of the lines extended along the axes of the greater superficial petrosal nerve and arcuate eminence. A morphometric analysis determined the average lengths of the respective sides of the complex to be 13.2 mm +/- 2.6 x 22.2 mm +/- 2.8 x 16.4 mm +/- 3.4 x 16.6 mm +/- 1.5 (beginning at "1" and proceeding sequentially), with an approximate area of the construct equal to 2.9 square centimeters.(ABSTRACT TRUNCATED AT 250 WORDS)

Cavernous Sinus↗
PubMed1994

Winter evaluation of a postmilking powdered teat dip.

A powdered teat dip designed for winter usage was evaluated for bacteriological efficacy and teat conditioning qualities. A positive control, natural exposure field trial was conducted for 3 mo on 509 lactating cows. Two sets of cows, primiparous and multiparous, were used. The trial compared efficacy of a powdered teat dip with a teat dip of 1% iodine plus 10% glycerin. Bacteriological efficacy among primiparous cows was equivalent for all major mastitis pathogens, environmental pathogens, and streptococci other than Streptococcus agalactiae. Efficacy was not equivalent against coagulase-negative staphylococci and all mastitis pathogens. Results suggested that the positive control product was more efficacious. Among multiparous cows, efficacy was equivalent against environmental mastitis pathogens and bacteriologically negative, clinical mastitis. The products were not equivalent against Staphylococcus aureus, coagulase-negative staphylococci, or all major mastitis pathogens, once again suggesting that the positive control product was more efficacious. Data indicated that germicidal activity of the powdered dip was not sufficient to reduce the incidence of new IMI caused by contagious or minor pathogens normally associated with teat skin. Application of a powdered postmilking teat dip during 3 winter mo in Idaho resulted in improved teat end condition among primiparous and multiparous dairy cows. Teat skin condition improved among primiparous but not among multiparous cows.

Allantoin↗
PubMed1994

Extradural temporopolar approach to lesions of the upper basilar artery and infrachiasmatic region.

Surgical access to the parasellar, infrachiasmatic, and posterior clinoid regions has traditionally been accomplished through an intradural pterional or subtemporal approach. However, for large or complex lesions in these locations, such traditional trajectories may not afford sufficient exposure for complete obliteration of the pathological process. The authors describe an anterolateral transcavernous approach to this region that includes the following components: 1) extradural removal of the sphenoid wing and exposure of the superior orbital fissure and foramen rotundum; 2) removal of the anterior clinoid process via the anterolateral route; 3) decompression of the optic canal; 4) extradural retraction of the temporal tip; 5) transcavernous mobilization of the carotid artery and third cranial nerve; and 6) removal of the posterior clinoid process. This method results in enhanced exposure with minimal brain retraction and preservation of the temporal tip bridging veins. This approach has been used in 22 patients: 10 with basilar top aneurysms, eight with craniopharyngiomas, one with a tuberculum sellae meningioma, and two with trigeminal neuromas; the last patient had a carotid-cavernous fistula and a concomitant pituitary adenoma. Complete clip ligation was performed for all 10 basilar artery aneurysms, and gross total resection was achieved with preservation of the pituitary stalk in all tumor cases. Microscopic total resection was not possible in two cases of craniopharyngioma due to hypothalamic invasion. Two patients suffered transient postoperative hemiparesis, and one patient has persisting weakness; however, no patient followed for more than 6 months suffered any persistent cranial nerve morbidity. It is concluded that this procedure can serve as an alternative to either the transsylvian or subtemporal approaches when cranial base pathologies are large or complex.

Adolescent↗
PubMed1994

Cardiac performance enhancement and hypervolemic therapy.

This article discusses guidelines the authors have established in managing patients with ruptured intracranial aneurysms and associated vasospasm. These guidelines represent methods of improving cardiac output or the ideal cardiac indices, to improve or maximize cerebral blood flow and potentially improve outcome. The guidelines for hypervolemic therapy for the volume and timing of intravenous fluid administration and the target cardiac performance parameters also are discussed.

Adolescent↗
PubMed1989

Dose-dependent inhibition of theophylline metabolism by disulfiram in recovering alcoholics.

The influence of disulfiram on theophylline metabolism was studied in 20 recovering alcoholics. Ten of the patients, who were selected at random, received 250 mg of disulfiram daily. The other 10 patients received 500 mg of disulfiram daily. Two single-dose studies of theophylline kinetics were performed--one as a baseline control and the other after 1 week of treatment with disulfiram. With disulfiram pretreatment, the plasma clearance of theophylline was decreased from 105.7 +/- 10.2 (mean +/- SEM) to 83.1 +/- 8.1 ml/kg per hour (p less than 0.001) in the 250 mg group and from 94.3 +/- 13.3 to 65.4 +/- 10.7 ml/mg per hour (p less than 0.001) in the 500 mg group. The elimination half-life was prolonged significantly in both groups. The percent reduction in theophylline clearance was greater in the 500 mg group (32.5 +/- 3.1; range, 21.6 to 49.6) than it was in the 250 mg group (21.2 +/- 1.7; range, 14.6 to 29.6; p less than 0.01). Disulfiram decreased the formation of all theophylline metabolites in smokers in both treatment groups. In each group, the hydroxylation pathway was affected more than the demethylation pathway. These data indicate that at therapeutic doses disulfiram exerts a dose-dependent inhibitory effect on theophylline metabolism. Depending on the dose of disulfiram, a dose reduction of theophylline by as much as 50% may be necessary to minimize the risk of toxicity.

Adult↗