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Biomedical subjects

D T Cross

Publications and source records attributed to D T Cross.

36 records · Page 2Linked to original sources
PubMed1995

Severe thrombocytopenia following intraarterial papaverine administration for treatment of vasospasm.

Selective intraarterial infusion of papaverine is used in the treatment of symptomatic cerebral vasospasm. The authors report two episodes of severe thrombocytopenia in a patient that were related to intraarterial administration of papaverine. A 70-year-old man with a right internal carotid artery aneurysm underwent craniotomy and aneurysm clipping. He became lethargic 8 days after the hemorrhage occurred. Cerebral angiography revealed moderate vasospasm. In addition to hypervolemic-hypertensive therapy, the patient was treated on two occasions with intraarterial administration of papaverine. Within 24 hours of both treatments he developed severe thrombocytopenia. On one occasion epistaxis requiring transfusion of blood products occurred. Laboratory data support the diagnosis of immune-mediated papaverine-induced thrombocytopenia. The authors conclude that intraarterial administration of papaverine for treatment of vasospasm can be associated with severe, rapidly reversible thrombocytopenia.

Aged↗
PubMed1995

Intraoperative digital subtraction angiography: a review of 112 consecutive examinations.

PURPOSE: To examine the effect of intraoperative angiography on neurosurgery and angiographic technical success, safety, and accuracy. METHODS: Angiographic studies, surgical reports, and hospital records were reviewed retrospectively for 112 consecutive procedures in which intraoperative angiography was performed during neurosurgery. The results of conventional postoperative angiograms in 28 of the 112 procedures were also reviewed. A portable digital subtraction angiography unit was used for all patients. Decisions in the operating room were based on review of stored videotaped images. RESULTS: Eighteen studies were obtained in 14 patients after arteriovenous malformation resection. Unsuspected residual nidus was identified and resected in 3 patients. The intraoperative angiogram also altered therapy for 2 patients undergoing staged resections of arteriovenous malformations. Sixty-six studies were performed after aneurysm clipping, with clinically significant changes in surgical therapy made in 5 patients. Of 28 examinations after carotid endarterectomy, 3 led to revision. Two complications of angiography occurred. One led to a permanent neurologic deficit, yielding a complication rate of 1.5% for stroke. Two examinations could not be completed because of technical factors. Two false-negative examinations were identified on postoperative studies. One patient with a normal intraoperative study after carotid endarterectomy thrombosed the repaired internal carotid artery after surgery. CONCLUSIONS: Intraoperative angiography altered surgery in 13 of 112 procedures on 104 patients. This study supports the use of intraoperative angiography in arteriovenous malformation resection and in complex aneurysm surgery, but not for routine carotid endarterectomy.

Angiography, Digital Subtraction↗
PubMed1993

Interventional neuroradiology.

Interventional neuroradiology continues to play an increasing role in the treatment of intracranial aneurysms, the treatment of vasospasm related to subarachnoid hemorrhage, and the treatment of vascular malformations and fistulae of the brain and spine. New techniques for aneurysm embolization are examined, such as detachable coil systems, as are reports of intracranial angioplasty and superselective papaverine infusion for vasospasm following aneurysm rupture. Results of investigations of arteriovenous malformation embolizations and recent analyses of risk factors associated with arteriovenous malformations are discussed. New approaches to tumor embolization are presented, and there are new data on angioplasty for cerebral atherosclerotic disease. Local fibrinolytic therapy in the treatment of patients with acute intracranial arterial or venous sinus thrombosis is evaluated.

Angioplasty, Balloon↗
PubMed1992

Body temperature fluctuations in the periparturient horse mare.

The objective of this study was to determine the pattern of mare deep body temperature fluctuations associated with parturition using biotelemetry. A radio transmitter was implanted in one flank in each of six mares. Telemetered data were received by a pair of antennae placed at right angles in a 3.3 x 6.6-m stall and stored on a computer hard disk. Hourly temperature data were recorded for the period of -168 through 168 hours post partum. A decrease of 0.76 degrees C in body temperature began at 4 hours prior to parturition (P < 0.1) then decreased rapidly between the 3 hours prior to and the time of parturition (Time 0). The lowest mean body temperature recorded was at the time of parturition (36.58 +/- 0.16 degrees C; P < 0.001). A supranormal increase in mean body temperature began one hour post partum, peaked at 38.02 +/- 0.08 degrees C and remained elevated for 48 hours post partum until gradually decreasing to the level of the prepartum mean by 106 hours.

Journal Article↗
PubMed1992

Confusion and memory loss from capsular genu infarction: a thalamocortical disconnection syndrome?

We examined six patients with an abrupt change in behavior after infarction involving the inferior genu of the internal capsule. The acute syndrome featured fluctuating alertness, inattention, memory loss, apathy, abulia, and psychomotor retardation, suggesting frontal lobe dysfunction. Contralateral hemiparesis and dysarthria were generally mild, except when the infarct extended into the posterior limb. Neuropsychological testing in five patients with left-sided infarcts revealed severe verbal memory loss. Additional cognitive deficits consistent with dementia occurred in four patients. A right-sided infarct caused transient impairment in visuospatial memory. Functional brain imaging in three patients showed a focal reduction in hemispheric perfusion most prominent in the ipsilateral inferior and medial frontal cortex. We infer that the capsular genu infarct interrupted the inferior and anterior thalamic peduncles, resulting in functional deactivation of the ipsilateral frontal cortex. These observations suggest that one mechanism for cognitive deterioration from a lacunar infarct is thalamocortical disconnection of white-matter tracts, in some instances leading to "strategic-infarct dementia."

Aged↗
PubMed1991

Telemetric monitoring of body temperature in the horse mare.

The objective of this study was to develop a radiotelemetric system capable of frequent monitoring of mare body temperature. A radio transmitter was implanted in the flank of each of four mares. Telemetered data were received by a pair of antennae placed at right angles in a 3.3 x 6.6-m stall and stored on a computer hard disk. The data were recorded every 5 minutes except when mares were out of the stall for a 1- to 2- hour exercise period. No effect of environmental temperature, ranging from 5 degrees C to 30 degrees C, on mare body temperature was apparent. The radiotelemetric system used in this study was effective for frequent measurement of mare body temperature.

Journal Article↗
PubMed1991

Uterine electromyographic activity in horse mares as measured by radiotelemetry.

The objective of this study was to determine if radiotelemetry could be used to measure myometrial electromyographic (EMG) activity. A radio transmitter with one pair of biopotential leads was implanted in the flank ipsilateral to the pregnant uterine horn at least five weeks prior to the expected date of parturition in two mares. The biopotential leads were implanted in the base of the pregnant uterine horn. Telemetered data were received by a pair of antennae placed at right angles in a 3.3 by 6.6-m stall. Data were recorded on VHS format videocassette tapes continuously for the 24h prior to and following parturition. Simultaneous physiograph recordings were made as a hard copy reference. In addition, 10 mg of prostaglandin F(2 alpha) was administered to two mares in the luteal phase of the estrous cycle. Myometrial EMG during parturition was increased similarly to that of previously published reports that used myometrial electrodes wired directly to a physiograph. Prostaglandin F(2 alpha) also caused an increase in myometrial EMG activity within 8 min of administration. This study demonstrated that radiotelemetry can be used for measuring myometrial EMG activity.

Journal Article↗
PubMed1991

Non-neoplastic pineal cysts.

We identified 53 patients with non-neoplastic cysts of the pineal gland. In contrast to patients with pineal neoplasms, pineal cysts are usually asymptomatic. They infrequently obstruct the aqueduct to cause hydrocephalus or compress the tectum to produce the neuro-ophthalmologic signs of dorsal midbrain dysfunction. Obstructive hydrocephalus was present in only five patients (9.4%); three of them showed clinical signs of Parinaud's syndrome. CT and MRI typically reveal a cystic mass that averages 1.6 cm in anteroposterior (A-P) diameter with calcification at the periphery and faint rim-like contrast enhancement. Sagittal MRI is the most useful diagnostic test because it shows the anatomic relationship of the cyst to the aqueduct. The mass may compress the tectum and distort the proximal aqueduct; occasionally a large cyst may occlude the aqueduct. All patients with obstructive hydrocephalus had cysts greater than 2.0 cm in A-P diameter. Nine patients had suboccipital craniotomy. In all of them, the cysts contained clear fluid and were easily removed. We advocate conservative management with clinical observation of these benign lesions that may be developmental variants of normal pineal gland.

Adolescent↗
PubMed1990

Effect of xylazine on interovulatory interval and serum progesterone concentrations in the horse mare.

The objective of this study was to determine the effect of the alpha2-adrenergic agonist, xylazine, on interovulatory interval and progesterone concentrations in the horse mare. Mares were assigned to one of four treatments: Group 1 (controls) received an intramuscular injection (i.m.) of 5 cc saline (n=6), Group 2 received 10 mg prostaglandin F2alpha (PGF2alpha) i.m. (n=5), Group 3 received 500 mg xylazine i.m. (n=6) and group 4 received an intravenous injection (i.v) of 350 mg xylazine (n=6). Treatment was administered on Day 10 of the estrous cycle (Day 0=Day of detected ovulation). There was no difference in length of interovulatory interval between PGF2alpha-treated mares and control mares (mean+/-SEM; 18.8+/-1.0 versus 21.7+/-1.6 d). When compared with either xylazine-treated group, PGF2alpha-treated mares had a shorter interovulatory interval (18.3+/-1.0 d versus 22.2+/-0.6 and 22.8+/-1.3 d, respectively; P<0.05). There was no difference in the length of interovulatory interval between control mares and either xylazine-treated group. At the time of treatment all mares had progesterone concentrations>10 ng/ml, therefore the onset of luteolysis was defined as the day of the estrous cycle when progesterone concentrations decreased below 10 ng/ml. In PGF2alpha-treated mares, this event occurred earlier than in any other group (Day 11.2+/-0.2 of the estrous cycle versus 16.0+/-1.3 for control, Day 15.7+/-0.2 for Group 3 and Day 15.2+/-0.6 for Group 4; P<0.002). It was concluded that a single treatment with xylazine, either by an intramuscular or intravenous route, had no significant effect on interovulatory interval or progesterone concentrations in horse mares.

Journal Article↗
PubMed1988

Uterine contractions in nonpregnant and early pregnant mares and jennies as determined by ultrasonography.

Uterine contractions in 8 nonpregnant and 13 pregnant mares were studied using ultrasonography. A 1-min video tape recording was made of longitudinal real-time images of the uterine body. An overall uterine contractile activity score (0 = no or minimal activity to 4 = maximal activity) was assigned to each video tape segment. There was a day effect (P less than .01) and an interaction (P less than .01) of reproductive status X day. Uterine activity scores were highest on d 14 to d 18 (d 0 = day of ovulation) for nonpregnant mares and on d 10 to d 14 for pregnant mares. Uterine activity scores on d 10, d 12, and d 14 were greater (P less than .02) for pregnant mares (2.5 +/- .3, 3.1 +/- .3, and 3.2 +/- .1, respectively) than for nonpregnant mares (1.2 +/- .3, 1.5 +/- .3, and 2.6 +/- .3). Uterine activity scores for six pregnant and five nonbred jennies were assigned daily from d 0 to d 24. There were main effects of reproductive status and day (P less than .01) and an interaction of status X day (P less than .01). Uterine activity scores for pregnant jennies were highest on d 13 and d 14 and then declined. In the nonbred jennies, scores were highest on d 14 to d 20. The mean score on d 13 was greater (P = .05) in pregnant jennies (2.8 +/- .2) than in nonbred jennies (1.9 +/- .5).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

The effect of estrogen, progesterone and prostaglandin F2 alpha on uterine contractions in seasonally anovulatory mares.

Uterine contractions were studied in two experiments utilizing ultrasonography and seasonally anovulatory mares. A one-minute ultrasound scan was done to produce longitudinal real-time images of the uterine body and an overall uterine contractile activity score (0 = no or minimal activity to 4 = maximal activity) was assigned to each scan. In experiment 1, a two-hour uterine activity trial (one score every 10 minutes) was done in mares given a single injection of prostaglandin F2 alpha (PGF2 alpha group; n = 4) and in control mares (n = 4). There was no difference between the two groups over the two-hour trial (mean activity score averaged over the two-hour trial: PGF2 alpha group, 0.2; control group, 0.1). In experiment 2, 16 mares were randomly assigned to one of four groups: 1) controls (corn oil vehicle), 2) 1 mg estradiol 17 beta on days 0 to 9 and 100 mg progesterone on days 10 to 20 (E2--greater than P4 group), 3) 100 mg progesterone on days 0 to 20 (P4 group), and 4) 100 mg progesterone on days 0 to 9 and 1 mg estradiol 17 beta + 100 mg progesterone on days 10 to 20 (P4--greater than E2 + P4 group). Uterine activity was assessed for each mare daily. The day by group interaction was significant. Scores for the E2--greater than P4 group were greater on days 4 to 11 (P less than .05) than for the other three groups. From day 14 to 21, scores did not differ among the three steroid-treated groups (except on day 15), but the scores averaged over each steroid-treated group were greater for each day (P less than .1 or .05) than for the controls (except on day 17).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1982

Ethnicity as a variable in responses to California Psychological Inventory items.

The responses of Black and White subjects to the California Psychological Inventory items were compared. On the average, 34% in each of the 18 scales showed significant differences. Approximately two-thirds of the significant items for the males were also significant for the females. Blacks responded in the keyed direction for over 23% of the items. The results of this study were consistent with the results of previous studies. The implications of the results of this research are discussed. It is suggested that future development of tests of this nature carefully consider the socio-cultural factors that might contribute to differential responses to test items on objective personality tests as assessment devices. Scores obtained by Blacks on the CPI should be interpreted against the background of the results of this study.

Journal Article↗
PubMed1978

Differential effects of ethnic membership, sex, and occupation on the California Psychological Inventory.

This study investigated the effects of race, sex, and occupation on college students' responses to the California Psychological Inventory. Analyses of variance of the standard CPI scales indicated numerous race, sex, and race X sex effects. A comparison of the results of factor analyses of the responses of black and white subjects (within each sex) indicated a similarity in factor structure between the two female groups, but not for the two male groups. These findings suggested that, due to these major differences in scale means and factor structure, care be taken in interpreting scores from the CPI when they are obtained from nonwhite populations.

Journal Article↗
PubMedDate not supplied

CT and MRI of stroke.

A review of the CT and MRI features of stroke imaging is presented. The pathophysiology of stroke is discussed as a basis for understanding the neuroimaging findings. Neuroimaging is divided according to the time interval between ictus and imaging: hyperacute, acute, subacute, and chronic. Newer MR stroke imaging techniques such as perfusion imaging and diffusion-weighted imaging are presented.

Brain↗
PubMedDate not supplied

Polyvinyl alcohol particle size and suspension characteristics.

PURPOSE: To evaluate the size and shape of commercially available polyvinyl alcohol (PVA) particles and to determine whether they change in size when suspended in nonionic contrast and in a solution of nonionic contrast and absolute alcohol. METHODS: The two-dimensional area and the long and short axis of PVA particles from several different vendors were measured using a light microscope attached to a video system and an image-processing software program. Particles were measured as packaged (dry or suspended in saline), suspended in ioversol, and suspended in ioversol containing 30% alcohol. RESULTS: All brands of dry particles had similar microscopic appearances. The saline-suspended particles had fewer and finer perforations. After suspension in contrast, all sizes and brands of dry particles significantly increased in size. The particles packaged in saline did not expand. The addition of alcohol to the contrast did not consistently change particle size. Particle aggregation was similar in both contrast suspensions for all groups of particles. Particles less than 50 microns in size were rarely observed in any PVA preparation after suspension. CONCLUSIONS: The three dry PVA preparations seem to be similar. All increase significantly in size when suspended in nonionic contrast or contrast-alcohol solutions. The saline-packaged PVA particles were different from the dry variety and did not enlarge in contrast or contrast-alcohol solutions. Alcohol did not change the size or suspension characteristics of PVA particles. Particles less than 50 microns in size were rarely identified.

Contrast Media↗
PubMedDate not supplied

Effect of intraarterial papaverine on cerebral circulation time.

PURPOSE: To measure the mean cerebral circulation time (CCT) in patients with symptomatic vasospasm stemming from subarachnoid hemorrhage and to determine any change after papaverine treatment. METHODS: We studied 27 patients who received intraarterial papaverine from November 1992 to August 1995 to determine the CCT in 59 carotid territories. CCT was measured from the first image in which contrast was seen above the supraclinoid internal carotid artery to the peak filling of parietal cortical veins. Angiograms at the time of presentation were examined in 19 of the 27 patients. A control population of 19 patients (30 carotid territories) was also studied. RESULTS: The mean CCT on presentation was 6.8 seconds +/- 1.1. The prepapaverine mean CCT was 6.1 seconds +/- 1.2. The immediate postpapaverine mean CCT was 3.8 seconds +/- 0.8. CCT decreased in 58 of 59 territories treated with papaverine; the mean change was -35.7%. In eight of these patients, CCT rose on the following day to 6.1 seconds +/- 1.1. In the control group, mean CCT was 5.9 seconds +/- 0.8. The mean CCT in patients with subarachnoid hemorrhage was slightly prolonged on presentation relative to that in control subjects. CONCLUSION: Intraarterial papaverine produces a consistent decrease in CCT in patients with vasospasm.

Adult↗
PubMedDate not supplied

Transient obstruction of the internal carotid artery during angiography.

While performing carotid angiography in a 76-year-old man, we found that the right internal carotid artery repeatedly opened and closed during the examination. The patient experienced no related neurologic events. The explanation, confirmed at surgery, was that a flap associated with an atherosclerotic plaque had acted as a ball valve.

Aged↗