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Biomedical subjects

H Tung

Publications and source records attributed to H Tung.

At least 19 recordsLinked to original sources
PubMed2000

Use of hypertonic saline in the treatment of severe refractory posttraumatic intracranial hypertension in pediatric traumatic brain injury.

OBJECTIVES: To evaluate the effect of prolonged infusion of 3% hypertonic saline (514 mEq/L) and sustained hypernatremia on refractory intracranial hypertension in pediatric traumatic brain injury patients. DESIGN: A prospective study. SETTING: A 24-bed Pediatric Intensive Care Unit (Level III) at Children's Hospital. PATIENTS: We present ten children with increased intracranial pressure (ICP) resistant to conventional therapy (head elevation at 30 degrees, normothermia, sedation, paralysis and analgesia, osmolar therapy with mannitol, loop diuretic, external ventricular drainage in five patients), controlled hyperventilation (Pco2, 28-35 mm Hg), and barbiturate coma. We continuously monitored ICP, cerebral perfusion pressure (CPP), mean arterial pressure, central venous pressure, serum sodium concentrations, serum osmolarity, and serum creatinine. INTERVENTIONS: A continuous infusion of 3% saline on a sliding scale was used to achieve a target serum sodium level that would maintain ICP <20 mm Hg once the conventional therapy and barbiturate coma as outlined above failed to control intracranial hypertension. MEASUREMENTS AND MAIN RESULTS: The mean duration of treatment with 3% saline was 7.6 days (range, 4-18 days). The mean highest serum sodium was 170.7 mEq/L (range, 157-187 mEq/L). The mean highest serum osmolarity was 364.8 mosm/L (range, 330-431 mosm/L). The mean highest serum creatinine was 1.31 mg/dL (range, 0.4-5.0 mg/dL). There was a steady increase in serum sodium versus time zero that reached statistical significance at 24, 48, and 72 hrs (p < .01). There was a statistically significant decrease in ICP spike frequency at 6, 12, 24, 48, and 72 hrs (p < .01). There was a statistically significant increase in CPP versus time zero at 6, 12, 24, 48, and 72 hrs (p < .01). There was a statistically significant increase in serum osmolarity versus time zero at 12 hrs (p < .05) and at 24, 48, and 72 hrs (p < .01). Two patients developed acute renal failure and required continuous veno-venous hemodialysis; these were concurrent with an episode of sepsis and multisystem organ dysfunction. Both recovered full renal function with no electrolyte abnormalities at the time of discharge. CONCLUSION: An increase in serum sodium concentration significantly decreases ICP and increases CPP. Hypertonic saline is an effective agent to increase serum sodium concentrations. Sustained hypernatremia and hyperosmolarity are safely tolerated in pediatric patients with traumatic brain injury. Controlled trials are needed before recommendation of widespread use.

Acute Disease↗
PubMed1999

Cutaneomeningospinal angiomatosis (Cobb syndrome) with tethered cord.

A newborn presented with a skin-covered lumbar mass with a subcutaneous hemangioma and on a magnetic resonance image (MRI) revealed a tethered spinal cord with a local mass. The mass had signal characteristics compatible with a lipoma. An initial diagnosis of a lipomeningocele with tethered cord was made, and the patient underwent surgical exploration and subtotal resection of the mass. A follow-up MRI revealed that the cord was still tethered, but an additional mass was present. The initial mass with signal characteristics of lipomatous tissue was accompanied by a low-signal mass in the lumbosacral canal, ventral to the cord, and bilateral enlargement of the foramina at the lumbosacral level. Because of a concern for an intraspinal tumor, a second operative intervention was performed. Multiple biopsies of the mass inside the spinal cord, the nerve roots and at the level of the foramina revealed angiomas that had similar pathology in all the specimens. A partial resection of the masses and a release of the tethered cord was performed by sectioning the thickened filum terminale. The diagnosis of Cobb's syndrome was made. The unique association of a tethered cord and the Cobb syndrome is reported here.

Abnormalities, Multiple↗
PubMed1999

Evaluation of use and durability of polypropylene trans-tibial prostheses.

Forty-three (43) trans-tibial prostheses with a mean period of use of 33 months were evaluated in terms of utilisation and durability. The majority of the prostheses (80%) were worn by amputees with demanding occupations, such as farmers, fishermen and tradesmen. The prostheses were in use approximately 9 hours per day. No major or frequent breakdowns of the polypropylene prosthetic components were found. The suspension belts were the parts most frequently affected; a total of 32 needed replacement after an average 11 months of use. Eleven (11) prostheses were completely replaced, more than half at least partly because of socket-fitting problems. In all, socket-fitting problems were found in 15 prostheses, causing pain and consequently limitation of use. While the prosthetic polypropylene components were satisfactory, the rubber foot was a major cause of early breakdown. A total of 40 feet were replaced; their mean period of use before breakdown was 9 months. In practice, parts were frequently replaced at a later stage than desirable, meaning that there was frequent "overuse" of prostheses with worn parts. Measures were taken to increase the life span of the prosthesis: change in the design of the foot; issuing a spare foot with the prosthesis; strengthening the suspension belt. Additional evaluations are necessary to confirm the degree to which the findings are representative.

Adolescent↗
PubMed1996

The open Gamma Knife Center concept.

A freestanding Gamma Knife radiosurgery center has been open for just over 1 year in La Jolla, Calif., USA, located in the grounds of a medium-sized community hospital. The center employs a full-time medical physicist and neurosurgical nurse together with clerical personnel. The neurosurgeons and radiation oncologists are drawn from the entire community and bill their fees separately. Written protocols for each indication to be treated govern patient eligibility and suggested treatment algorithms. Additionally, each patient to be treated is presented in conference, and a treatment strategy (i.e., radiosurgery, craniotomy, conventional radiation therapy) is decided. Twenty new physicians and physicists have begun training to use the Gamma Knife in the first year. Certification must be achieved before a clinician can be physician of record.

California↗
PubMed1995

Presurgical localization of functional cortex using magnetic source imaging.

The boundaries of somatosensory cortex were localized noninvasively by means of a large-array biomagnetometer in six patients with mass lesions in or near eloquent cortex. The results were used by neurosurgeons and neurologists in preoperative planning and for reference in the operating room. The magnetic source imaging (MSI) localizations from somatosensory evoked potentials were used to predict the pattern of phase reversals measurable intraoperatively on the cortical surface, providing a quantitative comparison between the two measures. The magnetic localizations were found to be predictive in all six cases, with the two sets of localizations falling within an 8-mm distance on average. Somatosensory localizations using MSI offer accuracy in localizing somatosensory cortex stereotactically and in depicting its relationship to lesions. Such data are valuable preoperatively in assessing the risks associated with a proposed surgical procedure and for optimizing subsequent minimum-risk surgical strategy.

Adult↗
PubMed1994

Giant infectious intracavernous carotid artery aneurysm presenting as intractable epistaxis.

Infectious intracavernous carotid artery aneurysms usually present with ophthalmoplegia and/or signs of cavernous sinus thrombosis. We report an unusual case in which a patient with AIDS presented with intractable epistaxis secondary to rupture of a giant infectious intracavernous carotid artery aneurysm. Culture of the aneurysm grew mycobacterium avium intracellulare (MAI). The patient was treated successfully by excision of the aneurysm and reconstruction of the internal carotid artery with a saphenous vein interposition graft.

AIDS-Related Opportunistic Infections↗
PubMed1993

Monitoring of infectious intracranial aneurysms by sequential computed tomographic/magnetic resonance imaging studies.

To monitor the course of infectious intracranial aneurysms, repeated cerebral angiography has been recommended every 2 weeks during intravenous antibiotic therapy until the aneurysm has resolved or an operation has been performed. However, serial cerebral angiograms are not without some risk to the patient. We have prospectively studied five patients harboring a total of six infectious intracranial aneurysms by sequential computed tomography (CT) and/or magnetic resonance imaging (MRI) studies. All infectious aneurysms were initially identified by cerebral angiography and were treated with 6 to 8 weeks of intravenous antibiotics. The aneurysm size ranged from 4 to 10 mm. Sequential CT scans and/or MRI studies were obtained at 2- to 3-week intervals to monitor the course of the aneurysms. Three aneurysms enlarged during antibiotic therapy, and one remained unchanged in size. These four aneurysms were treated surgically. The two remaining aneurysms resolved with intravenous antibiotic therapy. Cerebral angiograms were obtained routinely preoperatively and were used to verify the resolution of the infectious aneurysms when they were no longer visible on CT or MRI. On the basis of this prospective study, we conclude that sequential thin-slice CT and/or MRI can effectively and safely monitor the course of infectious intracranial aneurysms once identified by cerebral angiography. This may reduce the need for serial angiography and reduce the ultimate risk in the management of infectious intracranial aneurysms.

Adult↗
PubMed1991

Molecular cloning and chromosomal localization of one of the human glutamate receptor genes.

Glutamate receptors are the predominant excitatory neurotransmitter receptors in the mammalian brain and are classified on the basis of their activation by different agonists. The agonists kainate and alpha-amino-3-hydroxy-5-methyl-4-isoxasolepropionic acid define a class of glutamate receptors termed kainate receptors. We have isolated and sequenced a human glutamate receptor (GluHI) cDNA and determined the chromosomal localization of its gene. The DNA sequence of GluHI would encode a 907-amino acid protein that has a 97% identity to one of the rodent kainate receptor subunits. Many of the changes between the predicted amino acid sequence of GluHI and the most similar rodent kainate receptor (GluRI) occur in a region of the protein encoded in rodents by an alternatively spliced exon. The extreme conservation between the human and rat kainate receptor subunits suggests that a similar gene family will encode human kainate receptors. The GluHI mRNA is widely expressed in human brain. The human gene encoding the GluHI subunit is located at 5q33. While the GluHI gene is not located near a chromosomal region associated with any human neurogenetic disorders, the homologous region on mouse chromosome 11 contains the sites of five neurologic mutations.

Amino Acid Sequence↗
PubMed1991

Surgical strategies and technical methodologies in optimal management of craniopharyngioma and masses affecting the third ventricular chamber.

Management of craniopharyngiomas and masses affecting the third ventricular chamber represents one of the most challenging problems confronting contemporary neurological surgeons. Given the devastating sequelae of surgical complications involved in approaches to the deep cerebral midline, surgical management requires a combination of sophisticated imaging, diagnostic pathology and surgical technique including ventricular microsurgery and stereotaxy and its attendant refinements. Surgical and non-surgical management is based upon the structural presentation of these masses as defined by detailed imaging studies. Operative objectives include histological definition, maximally feasible excision, cerebral spinal fluid diversion and relief of neurologic deficits created by masses affecting the third ventricular chamber.

Cerebral Ventricle Neoplasms↗
PubMed1991

Ventricular cerebrospinal fluid eosinophilia in children with ventriculoperitoneal shunts.

To determine the significance of cerebrospinal fluid (CSF) eosinophilia, the charts of 106 patients treated with shunt-related procedures during the calendar year 1985 were reviewed. Sixty-nine patients presented for a shunt revision; their charts were retrospectively reviewed from the time of shunt insertion until January, 1988. The remaining 37 patients had a ventriculoperitoneal shunt inserted during the study period and were subsequently followed to January, 1988. A total of 558 shunt-related procedures were performed on these patients during the study period, with a mean follow-up period of 6.9 years. The infection rate was 3.8%. Eosinophilia was diagnosed when eosinophils accounted for 8% or more of the total CSF white blood cell count. Ventricular CSF eosinophilia occurred in 36 patients sometime during their clinical course. These 36 patients required a mean of 8.5 shunt revisions, while the remaining patients required a mean of 2.5 revisions (p less than 0.001). Shunt infections were also more frequent in patients with eosinophilia (p less than 0.01). In no case was peripheral eosinophilia or a parasitic infection present. This study demonstrates that CSF eosinophilia is common in children with shunts. Children with this laboratory finding will experience more shunt failures. In addition, the new appearance of eosinophilia in the CSF of a patient with a shunt in place suggests the possibility of a shunt infection.

Brain Diseases↗
PubMed1991

Sixth nerve schwannomas. Report of two cases.

Two cases of sixth cranial nerve schwannoma are presented with a review of four other cases from the literature. The clinical spectrum, neuroradiological findings, and surgical outcome of the six cases are discussed. There are two distinct clinical presentations for sixth cranial nerve schwannomas. Type I sixth nerve schwannomas present with sixth nerve palsy and diplopia and arise from the cavernous sinus. In contrast, type II sixth nerve schwannomas have a more severe presentation with obstructive hydrocephalus, raised intracranial pressure, sixth nerve palsy, and diplopia. This type arises along the course of the sixth cranial nerve in the prepontine area. Cavernous sinus involvement in either type may preclude total surgical excision and indicate an increase possibility for recurrence.

Abducens Nerve↗
PubMed1990

Sampling of lung interstitial fluid in intact dog.

This paper reports a method of sampling fluid from the peribronchial-perivascular space (PBVS) of the lungs in intact closed chest dogs. The PBVS was sampled by introducing a wick catheter into the PBVS through a mediastinoscope. The right lymph duct was cannulated by the method of Vriem and Ohkuda [J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 54: 199, 1983] for collection of lymph to compare to peribronchial fluid. The colloid osmotic pressure (COP) of PVBS and right lymph duct fluid (RLDF) were compared in a series of dogs infused with lactated Ringer's solution (LR) and lactated Ringer's combined with three other conditions: left atrial balloon inflation (LRB), oleic acid infusion (LRO), and oleic acid infusion and left atrial balloon inflation (LROB). Prior to LR infusion, the volume of samples of fluid from the PBVS wicks was inadequate for measuring COP (less than 4 microliters). This difference was significantly only in the later samples at 3, 4, and 5 hr in the LR and LRB groups. In the LRO and LROB groups, protein content and amount of fluid sampled were greater than in the LR and LRB groups, but the mean COPs of the wick PBVS and RLDF were not significantly different. This method of directly sampling interstitial fluid from the lungs of dogs without thoracotomy confirms the high COP of fluid from the lung interstitium. This method of PBVS fluid sampling is potentially feasible in a human patient undergoing mediastinoscopy.

Animals↗
PubMed1990

Recurrent intraparenchymal hemorrhages from angiographically occult vascular malformations.

Thirteen patients with recurrent hemorrhages from angiographically occult vascular malformations are presented. Recurrent hemorrhages were indicated by the exacerbation of neurological deficits, the appearance of a new neurological deficit, or the onset of acute severe headache confirmed by evidence of recent hemorrhage on either computerized tomography or magnetic resonance imaging. Persistent neurological deficits correlated with an increased number of recurrent hemorrhages and their location. The median time from initial hemorrhage to the first recurrent hemorrhage was 12 months and the second rebleed generally occurred much earlier, with a median time of 2 months after the first. Eight patients underwent surgery with total excision and favorable results. One patient with a large pontine lesion underwent partial excision and has had a progressing neurological deficit from recurrent hemorrhages. Histopathological review confirmed the excised lesions to be cavernous angiomas. The authors conclude that angiographically occult vascular malformations are not the benign entity they were previously thought to be, and that they are prone to cause recurrent hemorrhages and persistent neurological deficits. Surgery can be effective and relatively safe in removing these lesions even in eloquent areas of the brain, but the necessity of occasional incomplete removal must be recognized in order to avoid creating an unacceptable neurological outcome.

Adolescent↗
PubMed1986

An experimental study on the effects of DMSO and indomethacin on cerebral circulation and intracranial pressure.

Albino rabbits with a cryogenic lesion to the left parieto-occipital cortex had cerebral blood flow studies (CBF) with the hydrogen clearance technique 24 hours after the insult. Similar subgroups were treated with DMSO (1 g/kg) bolus, DMSO (2 g/kg) infusion, indomethacin (20 mg/kg) bolus, and indomethacin followed by DMSO. Following DMSO bolus administration there was an immediate rise in CBF over both hemispheres, with a significant paradoxical decrease at 30 minutes, followed by a second smaller rise at 60 minutes. With DMSO infusion, the rise in CBF was sustained throughout the infusion period with no paradoxical decrease. With indomethacin there was an initial decrease immediately following the drug, and at 60 minutes there was a rise in the insulted left hemisphere, more than the right one. Indomethacin administration 15 minutes prior to DMSO failed to halt the immediate increase in CBF noted following DMSO bolus injection. These results, together with the changes that occurred in intracranial pressure and brain water content, are analyzed.

Animals↗
PubMed1983

Modification of the effect of dimethyl sulfoxide on intracranial pressure, brain water, and electrolyte content by indomethacin.

Albino rabbits with experimental brain oedema produced by a combined cryogenic left hemisphere and a metabolic 6-aminonicotinamide lesion were given indomethacin (20 mg/kg) fifteen minutes prior to dimethyl sulfoxide (DMSO) treatment (1 g/kg bolus). Intracranial pressure (ICP), systolic arterial pressure (SAP), central venous pressure (CVP), and EEG were continuously measured while the animals were being mechanically ventilated at a constant PaCO2 (38-42 torr). At the end of the run, brain H2O and electrolytes were measured. There was no significant reduction in ICP at 5 minutes and 15 minutes after DMSO. This was strikingly different to what occurred when DMSO alone was administered, when a significant reduction was noted (p less than 0.05). At 30 minutes there was a reduction in ICP in both the DMSO and the DMSO/indomethacin groups, but in the former it was 50% of the pretreatment values while in the latter it was only 24%. Because indomethacin is a proven prostaglandin inhibitor, these results suggest that these substances may play a role in the mechanism of action of DMSO.

Animals↗