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Biomedical subjects

Y Shapira

Publications and source records attributed to Y Shapira.

At least 145 records · Page 8Linked to original sources
PubMed1994

A critique of the intraoperative use of jugular venous bulb catheters during neurosurgical procedures.

We examined the intraoperative use of jugular venous bulb catheters in 100 consecutive patients undergoing neurosurgical procedures. The catheters were successfully placed after induction of anesthesia in 99 patients using an aseptic technique. The efforts were abandoned after four attempts in the remaining patient. The mean time of insertion was 94 s (SD 108, range 15-420). Carotid artery puncture on two occasions controlled by firm pressure was the only complication. Arterial blood pressure, PaCO2, PaO2, and jugular venous bulb oxygen saturations (SjVO2) were intermittently measured at set intervals throughout the operation. We defined cerebral venous desaturation as 1) none (SjVO2 > 50%), 2) mild (45% < SjVO2 < 50%), and 3) severe (SjVO2 < 45%). We graded the usefulness of the catheter as 1) not useful (NU), SjVO2 > 50% and PaCO2 > 25 mm Hg; 2) useful (U1), SjVO2 > 50% and PaCO2 < 25 mm Hg; intervention, no increase in PaCO2; 3) useful (U2), SjVO2 < 50% and PaCO2 < 25 mm Hg; intervention, increase PaCO2 to improve SjVO2; 4) useful (U3), SjVO2 < 50% and PaCO2 > 25 mm Hg; intervention, nonventilatory action to increase SjVO2 (e.g., infusion of mannitol). Mild desaturation was detected in 24 patients and severe desaturation was present in 17 patients. We found SjVO2 monitoring to be useful in 60 of 99 patients studied. It was useful for detecting and treating cerebral venous desaturation in 13 of 18 patients with intracranial hematomas (subdural, epidural, and intracerebral hematomas), 9 of 18 patients with intracerebral tumors, 27 of 45 patients with cerebral aneurysms, and 6 of 8 patients with other intracranial pathology.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Ketamine alters calcium and magnesium in brain tissue following experimental head trauma in rats.

We previously reported that the N-methyl-D-aspartate receptor antagonists dizocilpine maleate and ketamine improved the neurological severity score (NSS) after head trauma in rats. Other investigators have reported increased calcium and decreased magnesium following head trauma in untreated rats. The present study was designed to determine whether ketamine influences the concentrations of calcium and magnesium in brain tissue following head trauma. Eighty-six male Sprague-Dawley rats (180 +/- 15 g) were divided into eight groups. Groups A (no head injury) and C (head injury) received no treatment. Groups B (no head injury) and D-H (head injury) received ketamine. In groups D, E, and F, ketamine, 180 mg/kg i.p., was given 1, 2, and 4 h after head trauma, respectively. In groups G and H, ketamine, 120 and 60 mg/kg, respectively, was given 1 h after head trauma. After we killed the rats at 48 h, cortical slices were taken to measure tissue calcium and magnesium content by the inductively coupled plasma atomic emission spectroscopy method. In the contused hemispheres, calcium increased and magnesium decreased (p < 0.0001). Among the head-injured groups, the increase in brain tissue calcium was smaller in groups receiving 60 mg/kg of ketamine at 1 h or 180 mg/kg of ketamine at 1, 2, or 4 h than in the group not receiving ketamine. The decrease in brain tissue magnesium was smaller in the groups receiving 180 mg/kg of ketamine at 1 and 2 h than in the group not receiving ketamine.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Blood-brain barrier permeability, cerebral edema, and neurologic function after closed head injury in rats.

We previously described the time course of changes in neurologic status (as indicated by neurologic severity score [NSS]) and cerebral edema (as indicated by brain tissue specific gravity and water content) after closed head trauma in rats. The present study was designed to determine whether head trauma alters the integrity of the blood-brain barrier (BBB), the role of the BBB in edema formation and neurologic outcome, and the effect of MK-801 (a noncompetitive N-methyl-D-aspartate receptor antagonist) on BBB permeability. Rats in which cranial impact was delivered during ether anesthesia (n = 106) were killed at 15 min, 1, 2, 4, 10, and 24 h, and 2, 4, and 7 days. Control rats (n = 12) received no cranial impact. Subsets of head-injured rats killed at 4 and 24 h received MK-801 (3 mg/kg intraperitoneally) 1 h after injury. BBB permeability was assessed with intravenous injection of Evans Blue dye, cerebral edema was assessed by determining brain tissue specific gravity and water content, and neurologic status was assessed using NSS. Tissue extravasation of Evans Blue was maximal in the injured hemisphere 4 h after injury, but a residual BBB permeability defect was still evident as long as 4 days after the insult. In MK-801-treated rats, extravasation of Evans Blue in the injured hemisphere was not significantly different from that in the noninjured hemisphere.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Ultrasonographic evaluation of the endometrium and correlation with endometrial sampling in postmenopausal patients treated with tamoxifen.

Seventy-two asymptomatic, postmenopausal women treated with tamoxifen for breast cancer were studied prospectively with vaginal ultrasonography, followed by endometrial sampling. Seventy-one patients demonstrated an endometrial echo of more than 5 mm, and one displayed an endometrial echo of less than 5 mm. No patient with an endometrial echo of less than 5 mm displayed any endometrial pathology. Different endometrial pathologic conditions were found when the endometrial echo was over 5 mm. When classifying those patients whose ultrasonic endometrial widths were wider than 5 mm, on the basis of different endometrial histologic findings, no obvious correlation was found between the various pathologic endometrial findings and endometrial thickness. Thus, a "thicker" endometrial sonographic image did not necessarily correlate with pathologic endometrial findings. When ultrasonic endometrial thickness of 5 mm was considered the upper limit of normal, the sensitivity of ultrasonography in correlating to positive histologic findings was 91% and the specificity was 96%. These findings suggest that there is good correlation between endometrial width measured by ultrasonographic assessment and histologic findings.

Adult↗
PubMed1993

Transfusion-related adult respiratory distress syndrome.

Leukocyte antibodies are the major cause of nonhemolytic transfusion reactions. One of the less frequent but severe forms of this reaction is the adult respiratory distress syndrome, or transfusion-related acute lung injury. This rare phenomenon is the result of leukocyte antibodies forming immune complexes with granulocytes, complement activation, sequestration of activated granulocytes in the pulmonary capillary bed, and their degranulation associated with release of proteolytic and cytotoxic substances. This cascade causes endothelial damage with increased capillary permeability. Plasma fluids and proteins accumulate in the interstitial and intra-alveolar spaces, leading to respiratory insufficiency. We present two patients with transfusion-related adult respiratory distress syndrome associated with leukocyte HLA antibodies, who were successfully treated in our hospital. The pathogenesis, diagnostic measures and treatment of this uncommon yet critical condition is discussed.

Adrenal Cortex Hormones↗
PubMed1992

Fatal familial infantile glycogen storage disease: multisystem phosphofructokinase deficiency.

An infant girl of consanguinous Bedouin parents suffered from fatal early onset of progressive generalized muscle weakness. Her older brother suffered from similar weakness and cardiomyopathy, which led to his death at the age of 21 months. A muscle biopsy performed on the propositus at the age of 9 months was PAS-negative, and showed nonspecific myopathic changes. A second muscle biopsy, performed at 21 months of age, a few days before her death, and postmortem study of heart and liver, disclosed excessive extralysosomal glycogen storage and reduced phosphofructokinase-1 (PFK-1) activity. Because the genes encoded for PFK-1 in liver and muscle are located on separate chromosomes, the reduced enzyme activity in both tissues could not be related to a single mutation for this enzyme. Activity of 6-phosphofructose-2-kinase (PFK-2), a recently discovered physiological activator to all PFK-1 isozymes, was normal in the liver. The possibility that this multisystem PFK-1 deficiency may be related to the absence of a yet unknown activator, common to all PFK-1 isozymes, is discussed.

Biopsy↗
PubMed1992

Changes in brain polyamine levels following head injury.

The changes in polyamines levels in the brain after closed head injury were studied in rats. At 1 and 15 min, 24 and 48 h after closed head injury cortical tissue from the site of injury, from the contralateral region, and from remote areas were taken. The levels of the diamine putrescine and the polyamines spermine and spermidine were assayed by thin layer liquid chromatography of their dansyl derivatives. Head injury induced a significant increase in putrescine at 48 h at the site of injury and in the frontal lobe of the injured hemisphere, respectively. In the contralateral hemisphere only minor changes in putrescine were found. Spermine and spermidine showed minor changes at that time course. We have previously shown that at 24-48 h after injury, severe edema is found at the site injury. In order to study the role of putrescine in edema formation in this model we treated the traumatized rats with alpha-difluoromethyl-ornithine (DFMO), an inhibitor of ornithine-decarboxylase, the rate limiting enzyme in putrescine biosynthesis. This drug did not affect the level of edema 4 or 48 h after injury although it abolished the increase in putrescine. The effect of DFMO on blood-brain barrier function was studied, using Evans blue extravasation, at the early post-traumatic period (15 min-4 h), where a massive amount of dye is taken up by traumatized brain. No changes in the amount of dye extracted was found after DFMO treatment. On the other hand, DFMO had a beneficial effect on the neurological outcome, as evaluated by a set of clinical criteria.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Changes in the rate of formation and resistance to reabsorption of cerebrospinal fluid during deliberate hypotension induced with adenosine or hemorrhage.

Adenosine is recommended for induction of deliberate hypotension. Although its effects on brain vasculature and metabolism and intracranial pressure have been reported, its effects on cerebrospinal fluid dynamics have not. In this study the rate of cerebrospinal fluid formation (Vf), resistance to reabsorption of cerebrospinal fluid (Ra), and electroencephalogram (EEG) activity were determined in rabbits before and during decrease of cerebral perfusion pressure (CPP) with intravenous (iv) adenosine or hemorrhage. In the adenosine group (n = 6), Vf and Ra were determined at control CPP, at CPP of 50, 35, and 28 mmHg achieved with iv adenosine, and at CPP greater than 60 mmHg achieved with iv adenosine combined with iv phenylephrine. In the hemorrhage group (n = 6), Vf and Ra were determined at the first four experimental conditions only. Control values for Vf (9 +/- 3 and 9 +/- 4 microliter.min-1, mean +/- SD) and Ra (428 +/- 567 and 412 +/- 144 cmH2O.ml-1.min) did not differ between groups. In the adenosine group, Vf did not change significantly when CPP was decreased. However, in the hemorrhage group, Vf decreased significantly at CPP of 50 and 35 mmHg and became unmeasurable at CPP of 28 mmHg. Ra did not change significantly in either group. An increase of low-frequency (0.5-3.0 Hz) EEG activity and/or decrease of higher-frequency (3.5-30 Hz) EEG activity occurred at CPP of 28 mmHg in the adenosine group and at CPP of 35 mmHg in the hemorrhage group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗