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Biomedical subjects

S Tobias

Publications and source records attributed to S Tobias.

At least 19 recordsLinked to original sources
PubMed2005

Neuromuscular hamartoma of the trigeminal nerve in an adult.

A 36-year-old female presented with a long-standing history of headache. Computed tomography scan and magnetic resonance imaging revealed an enhancing lesion occupying the right Meckel's cave, enlarging the trigeminal ganglion and extending through the foramen ovale into the infratemporal fossa. A right frontotemporal extradural approach to the cavernous sinus was performed and a firm, pinkish lesion intermingled with nerve fibers enlarging the trigeminal ganglion and V3 branch was identified. Frozen section was suggestive of a neuromuscular hamartoma. The lesion was sub-totally resected to avoid injury to the motor branch. Neuromuscular hamartoma should be included in the differential diagnosis of cavernous sinus and cranial nerve lesions in adults.

Adult↗
PubMed2001

FiO2 and positive end-expiratory pressure as compensation for altitude-induced hypoxemia in an acute respiratory distress syndrome model: implications for air transportation of critically ill patients.

OBJECTIVES: To determine whether increases in FiO2 or positive end-expiratory pressure will compensate for hypoxemia resulting from exposure to 8000 feet (2440 m) of altitude in a model of acute respiratory distress syndrome. DESIGN: Intervention and crossover design. SETTING: Military research altitude chamber. SUBJECTS: Sixteen Yucatan miniature swine (Sus scrofa). INTERVENTIONS: Swine initially were placed on mechanical ventilation (zero positive end-expiratory pressure, 21% FiO2). Twelve animals had moderate to severe acute respiratory distress syndrome (50% to 70% FiO2 at sea level to maintain PaO2 of 50-70 torr [6.65-9.31kPa]) induced by intravenous oleic acid. Four animals were controls (no lung injury). The animals were taken to 8000 feet (2440 m) in an altitude chamber, and then stepwise increases of either 5% FiO2 (six animals) or 2.5 cm H2O positive end-expiratory pressure (six animals) were made until PaO2 values exceeded 75 torr (10.0 kPa). If PaO2 did not reach 75 torr (10.0 kPa), and time permitted, the animal was crossed over to the other group. MEASUREMENTS AND MAIN RESULTS: Arterial blood gases were drawn at baseline (sea level and at altitude) and after every change in ventilator settings. Positive end-expiratory pressure increases from 5 to 12.5 cm H2O were required to bring the PaO2 in the injured pigs to 75 torr (10.0 kPa). FiO2 increases did not achieve a PaO2 of 75 torr (10.0 kPa) for three of six animals despite reaching 100% FiO2. One animal crossed over from Fio2 to positive end-expiratory pressure and achieved a PaO2 of 75 torr (10.0 kPa) with 5 cm H2O of positive end-expiratory pressure. CONCLUSIONS: Fifty percent of the animals with lung injury had altitude-induced hypoxia that was resistant to increases in FiO2. Increases in positive end-expiratory pressure are more reliable than increases in FiO2 for correcting altitude-induced hypoxia in this model of acute respiratory distress syndrome.

Air Ambulances↗
PubMed2001

Giant cavernous sinus teratoma: a clinical example of a rare entity: case report.

OBJECTIVE AND IMPORTANCE: Teratomas represent 0.5% of all intracranial tumors. These benign tumors have tissue representative of the three germinal layers: ectoderm, mesoderm, and endoderm. Most teratomas are midline tumors located predominantly in the sellar and pineal regions. Cavernous sinus location is very rare; only two purely intracavernous teratomas have been reported. CLINICAL PRESENTATION: A 14-year-old boy presented with a history of progressive right eye proptosis and visual acuity impairment, headaches, and a neuralgia-like facial pain in the right V1 distribution. A head computed tomographic scan and magnetic resonance imaging disclosed a large tumor filling the right cavernous sinus and extending into the ipsilateral middle fossa. These scans also demonstrated mixed signals derived from different tissues conforming to the tumor (fat, cartilage, muscle strands, bone, and a primordial tooth). Heterogeneous enhancement was seen after infusion of contrast medium. Significant bone erosion and remodeling was evident in the middle fossa floor and right orbit, with secondary proptosis. A presumptive diagnosis of mature teratoma was made. INTERVENTION: With the use of a right frontotemporal interfascial approach, a combined extra- and intradural dissection of the tumor was performed. The lesion entirely occupied the cavernous sinus, laterally displacing the Gasserian ganglion and trigeminal branches (predominantly V1 and V2). The internal carotid artery and Cranial Nerve VI were medially displaced by the tumor mass. The lesion was composed of different tissues, including hair, fat, cartilage, muscle, nerve-like tissue, bone, and a primordial tooth. The tumor was removed completely, and the pathological report confirmed the diagnosis of a mature teratoma. There was no evidence of recurrence at the 8-month follow-up examination. CONCLUSION: Because of the lesion's location in the lateral wall of the cavernous sinus, a total removal was achieved with the use of standard microsurgical techniques. Knowledge of the microanatomy is essential in treating intracavernous pathology. We present the third reported case of a giant mature teratoma of the cavernous sinus.

Adolescent↗
PubMed1999

Transesophageal echocardiographic visualization of left ventricular malpositioned pacemaker electrodes: implications for lead extraction procedures.

Two cases of malpositioned LV electrodes are presented. Transesophageal echocardiography (TEE) allowed for a careful inspection of left-sided leads and for tracking their course. One LV and two right-sided leads were safely retrieved with TEE monitoring. One chronic LV lead was left in place as it was heavily fibrosed. TEE was helpful in the inspection and monitoring of the extraction and also in guided traction efforts. This is the first published report of echocardiographic visualization of the lead retrieval procedure.

Adult↗
PubMed1998

Ketoconazole inhibition of triazolam and alprazolam clearance: differential kinetic and dynamic consequences.

BACKGROUND: Kinetic and dynamic consequences of metabolic inhibition were evaluated in a study of the interaction of ketoconazole, a P4503A inhibitor, with alprazolam and triazolam, two 3A substrate drugs with different kinetic profiles. METHODS: In a double-blind, 5-way crossover study, healthy volunteers received (A) ketoconazole placebo plus 1.0 mg alprazolam orally, (B) 200 mg ketoconazole twice a day plus 1.0 mg alprazolam, (C) ketoconazole placebo plus 0.25 mg triazolam orally, (D) 200 mg ketoconazole twice a day plus 0.25 mg triazolam, and (E) 200 mg ketoconazole twice a day plus benzodiazepine placebo. Plasma concentrations and pharmacodynamic parameters were measured after each dose. RESULTS: For trial B versus trial A, alprazolam clearance was reduced (27 versus 86 mL/min; P < .002) and apparent elimination half-life (t1/2) prolonged (59 versus 15 hours; P < .03), whereas peak plasma concentration (Cmax) was only slightly increased (16.1 versus 14.7 ng/mL). The 8-hour pharmacodynamic effect areas for electroencephalographic (EEG) beta activity were increased by a factor of 1.35, and those for digit-symbol substitution test (DSST) decrement were increased by 2.29 for trial B versus trial A. For trial D versus trial C, triazolam clearance was reduced (40 versus 444 mL/min; P < .002), t1/2 was prolonged (18.3 versus 3.0 hours; P < .01), and Cmax was increased (2.6 versus 5.4 ng/mL; P < .001). The 8-hour effect area for EEG was increased by a factor of 2.51, and that for DSST decrement was increased by 4.33. Observed in vivo clearance decrements due to ketoconazole were consistent with those anticipated on the basis of an in vitro model, together with in vivo plasma concentrations of ketoconazole. CONCLUSION: For triazolam, an intermediate-extraction compound, impaired clearance by ketoconazole has more profound clinical consequences than those for alprazolam, a low extraction compound.

Administration, Oral↗
PubMed1994

Relationships between language and gesture in normally developing and late-talking toddlers.

Seventeen toddlers with specific expressive language delay (14 boys and 3 girls between 18 and 33 months of age) were compared to two control groups, one matched for language production and the other matched for age and language comprehension, on measures of spontaneous and imitated gesture production. Late talkers performed like age/comprehension-matched controls on all experimental measures of gesture production and on production of later appearing, more symbolic gestures as reported by parents. Late talkers performed like language-matched controls on earlier appearing communicative gestures and gestural routines as reported by parents. All three groups produced more gestures in canonical imitation conditions than spontaneously. Results are discussed in the contexts of the Local Homology Model and characteristics of toddlers with specific expressive language delay.

Child Language↗
PubMed1992

Communicative gestures in children with delayed onset of oral expressive vocabulary.

Use of communicative gestures in a group of children with delayed onset of expressive oral vocabulary (late talkers) was compared with such use among normal-language-matched controls and age-matched controls. Analyses revealed that late talkers used significantly more communicative gestures and for a greater variety of communicative functions than did language-matched controls. However, a 1-year follow-up revealed that 4 of the late talkers remained delayed (truly delayed late talkers) and 6 caught up (late bloomers). Reanalyses of Year 1 data based on these follow-up outcomes demonstrated that only late bloomers used more communicative gestures than did language-matched controls. Truly delayed late talkers did not differ from language-matched controls either for number of gestures, type of gestures (symbolic vs. nonsymbolic), or number of different functions for which gestures were used. Late bloomers also used more communicative gestures than did age-matched controls, suggesting that they (the late bloomers) were using gestures to compensate for their small oral expressive vocabulary. Results are discussed in the context of early predictors of risk for language impairment and relationships between language and cognition.

Child Language↗
PubMed1992

Effect of T-2 toxin on egg production and hatchability in laying hens.

The effect of diets containing different levels of T-2 toxin on egg production and hatchability was studied in a four-week experiment using 100 laying hens of the SSL hybrid line and 10 cocks divided into 10 groups. Another aim of the experiment was to investigate how effectively the increased dietary vitamin E content neutralized the adverse effects of T-2 toxin. The diet of the control group (C) contained no mycotoxin, while those of the experimental groups included the following levels of T-2 toxin: groups 1, 2 and 3: 1 mg/kg, groups 4, 5 and 6: 5 mg/kg; groups 7, 8 and 9: 10 mg/kg. Vitamin E was added to the diet of groups C, 1, 4 and 7 at a rate of 50 mg/kg while to that of groups 2, 5 and 8 at a rate of 100 mg/kg. To the diet of groups 3, 6 and 9 no vitamin E was added. Contamination of the diet with T-2 toxin markedly decreased egg production and impaired hatchability. The production decrease was proportional to the T-2 toxin concentration of the diet. Increased dietary vitamin E concentration exerted no influence on egg production. However, during the first week of the experiment it significantly (P < 0.01) decreased the number of infertile eggs and significantly (P < 0.01) improved the hatching percentage. Dietary vitamin E concentration was in positive correlation with the hatching percentage; this correlation was rather close (r = 0.74) in the first week of the experiment.

Animals↗
PubMed1991

Language and gesture in late talkers: a 1-year follow-up.

A 1-year follow-up of relationships between language and symbolic gesture in 10 children with delayed onset of early lexical skills (Thal & Bates, 1988a) is reported. Original data are reevaluated in light of new knowledge about which late talkers continued to be significantly delayed 1 year later (truly delayed) and which ones had "caught up" (late bloomers). Results showed that all 4 children who were truly delayed at follow-up had been delayed in language comprehension at the first visit, but the 6 late bloomers had been at the same level as their age-matched controls. In addition, truly delayed late talkers had been significantly poorer on all of the gesture tasks than late talkers who caught up.

Child, Preschool↗
PubMed1983

Cholecystectomy without drainage.

A review of 10 years' experience with cholecystectomy by one surgeon has been reported. The figures indicate that cholecystectomy without drainage is safe and substantially cost effective. The author urges all who are enamoured with the Penrose drain to reevaluate their technique.

Adolescent↗