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Biomedical subjects

A Schubert

Publications and source records attributed to A Schubert.

At least 55 records · Page 3Linked to original sources
PubMed1997

[Differentiation between glomerular and non-glomerular erythrocyturia: what is the value of differential microhematuria diagnosis?].

A few years ago, a new and simple method has been proposed to help guiding the investigation of microhematuria. This method which consists in quantifying the percentage of deformed polymorphous erythrocytes in the urinary sediment using phase contrast microscopy allows to distinguish glomerular from non-glomerular erythrocytes. In this paper, we have reviewed the recent literature concerning this approach and have discussed the conclusions according to our own experience based on the analysis of 147 patients presenting with microhematuria. Our results demonstrate that this technique is still limited by the difficulty to obtain well-defined cut-off values which effectively differentiate renal from urologic diseases. Thus, only extreme results showing either the total absence or the presence of a very high percentage of dismorphic erythrocytes appear to be helpful for the physician. Despite the introduction of this new method, many patients with microhematuria are insufficiently investigated.

Diagnosis, Differential↗
PubMed1997

Heart rate, heart rate variability, and blood pressure during perioperative stressor events in abdominal surgery.

STUDY OBJECTIVE: To define the behavior of power spectral heart rate variability (PSHR) during potentially stressful events in the perioperative period, and relate it to changes in blood pressure (BP) and heart rate (HR). DESIGN: Longitudinal clinical study. SETTING: Operating room and recovery suites of a large tertiary care referral center. PATIENTS: 26 ASA physical status I, II, and III patients undergoing elective abdominal surgery. INTERVENTIONS: Anesthesia was induced with thiopental sodium and fentanyl, and maintained with isoflurane/nitrous oxide (N2O)/relaxant or enflurane/N2O/relaxant. The trachea was intubated and intraabdominal surgery was performed. MEASUREMENTS AND MAIN RESULTS: Observations consisted of HR, noninvasive blood pressure, and PSHR. They were made before and after induction of anesthesia, tracheal intubation, and surgical incision, and during maximal surgical stimulation and skin closure. HR and mean arterial pressure (MAP) maxima were also recorded for one hour before and after emergence from anesthesia. PSHR was obtained using a special algorithm and data acquisition system for real time spectral analysis of the instantaneous HRversus time function. The HR power spectrum parameters analyzed were low-frequency (LFA; powerband = 0.04 to 0.10 Hz), respiratory-induced frequency (RFA; powerband = respiratory frequency +/- 0.06 Hz), and the ratio of LFA to RFA. With induction of anesthesia, only RFA power decreased significantly. LFA power reduction became significant only after intubation and continued so until after incision. Immediately after induction, the decline in RFA power (vs. preinduction) was more pronounced when compared with the decline in LFA power (76% vs. 34%; p = 0.01). Hence, the ratio LFA/RFA increased significantly after induction of anesthesia. It was significantly higher than at postintubation, preincision, or skin closure. A significant elevation in LFA, LFA/RFA ratio, and BP occurred with maximal abdominal surgical stimulation. Only preinduction LFA, RFA, and LFA/ RFA ratio were predictive of MAP changes with induction of anesthesia (p = 0.006). In 8 of the 15 patients who had MAP changes of at least 10 mmHg with induction, PSHR indices correctly predicted a change of this magnitude. Late intraoperative HR maxima were positively correlated with the change in HR and incision (r2 = 0.58; p < 0.01). The change in BP with incision was positively correlated with early postoperative HR maxima (r2 = 0.60; p < 0.01). CONCLUSIONS: On anesthetic induction, preoperative, but not intraoperative, spectral indices were predictive of BP changes. Power spectral analysis of HR may provide information about the autonomic state that is not evident from BP or HR. The HR power spectrum, in particular, indicated a striking autonomic imbalance immediately after the induction of anesthesia despite stable HR and BP. LFA and LFA/RFA ratio appeared to track sympathetic autonomic activation during abdominal surgical stimulation, but not during other perioperative stressor events.

Abdomen↗
PubMed1997

Tourniquet-induced hypertension correlates with autonomic nervous system changes detected by power spectral heart rate analysis.

STUDY OBJECTIVE: To determine the autonomic changes associated with pneumatic tourniquet-induced hypertension as measured by power spectral heart rate analysis (PSHR). DESIGN: Prospective study. SETTING: Tertiary teaching hospital. PATIENTS: 21 healthy-patients scheduled for lower extremity surgery, during which pneumatic tourniquet inflation was expected to exceed 90 minutes. INTERVENTIONS: Hemodynamic and PSHR data collected at 5 minute intervals during inflation of the pneumatic tourniquet. Tourniquet-induced hypertension (T-HTN) defined at 30% increase above baseline. MEASUREMENTS AND MAIN RESULTS: Blood pressure, heart rate, maximum changes in low frequency variability (LFa), high frequency variability (HFa), and their ratio (LFa/HFa) were measured. Of the 21 patients, 11 had T-HTN. A significantly greater increase in LFa and LFa/HFa ratio was seen in the T-HTN group, where patients were greater in age. LFa, HFa, and ratio were not significantly different with T-HTN until 60 minutes or greater. Best correlation with T-HTN occurred with maximum increase in LFa/HFa ratio compared with increase in LFa or decrease in HFa. CONCLUSION: Tourniquet hypertension correlated with activation of the sympathetic nervous systems, as measured by PSHR variables.

Adult↗
PubMed1997

Paternal transmission of X-linked placental dysplasia in mouse interspecific hybrids.

It has previously been shown that abnormal placental development, i.e., hyper- and hypoplasia, occurs in crosses and backcrosses between different mouse (Mus) species. These defects are caused mainly by abnormal growth of the spongiotrophoblast. The precise genetic basis for these placental malformations has not been determined. However, a locus that contributes to the abnormal development (Ihpd: interspecific hybrid placental dysplasia) has been mapped to the X chromosome. The X-chromosomal location of Ihpd and its site of action, that is the spongiotrophoblast, mean that normally only the maternally inherited Ihpd locus is active even in female fetuses. However, by making use of the X-chromosomal inversion In(X)IH, we have produced interspecific hybrid Xp0, in which the active X chromosome was inherited from Mus macedonicus males. In contrast to XX female and XY male conceptuses from this cross, which have hypoplastic placentas, the Xp0 female conceptuses have hyperplastic placentas. This finding supports the view that it is expression of the M. macedonicus Ihpd locus in the spongiotrophoblast that leads to hyperplasia due to an abnormal interaction with M. musculus autosomal loci.

Animals↗
PubMed1997

Occurrence of S and F1C/S-related fimbrial determinants and their expression in Escherichia coli strains isolated from extraintestinal infections.

The presence of S and F1C/S-related fimbrial determinants was determined in 462 E. coli strains obtained from different extraintestinal infections and in 162 control isolates of E. coli by using two different DNA probes: an oligonucleotide probe consisting of three oligonucleotides that bind specifically to the S adhesin gene and a polynucleotide probe which is not able to distinguish between S, F1C, and S-related sequences. The expression of S and F1C phenotypes was tested by dot enzyme immunoassay with the corresponding monoclonal antibodies. S fimbriae genotypes were observed more frequently in septic (25%) and urinary (12%) isolates of E. coli than in faecal and water isolates (1%) and often occurred together with O2, O6, O18 and O83 antigens. F1C/S-related fimbrial DNA was detected with a higher frequency in UTI isolates (26%) than in septic (16%) and faecal (10%) isolates and was most frequently associated with O4, O6, and O75 serotypes. Since the production of S and F1C fimbriae was comparatively rare in all clinical and control isolates of E. coli, DNA hybridization assays which allow the sensitive and specific detection of fimbrial determinants even in the absence of their expression are preferable to phenotypic assays.

Adhesins, Escherichia coli↗
PubMed1997

"I want to talk like everyone": on the use of multiple means of communication.

This qualitative case study is a description of a young man with autism who communicated using speech, sign language, facilitated communication, body language, and his mother's conversational supports. Participant observation, interviews, and review of records were used to explore his current and past communication practices. These practices illustrate his preference for speaking and the complexity of choosing among communication means on an ongoing basis. Although the young man and his mother differed in their thinking about communication, they revealed a common goal: for Michael to participate in ordinary life activities as a member with a voice.

Adult↗
PubMed1996

Intrathecal morphine for analgesia in children undergoing selective dorsal rhizotomy.

Selective dorsal root rhizotomy is performed for relief of spasticity in children with cerebral palsy. Postoperative pain relief can be provided by intrathecal morphine administered at the time of the procedure. We sought to define an optimal dose of intrathecal morphine in children undergoing selective rhizotomy, through a randomized, double-blinded prospective trial. After institutional approval and parental written informed consent, 27 patients, ages 3-10 years, were randomized to receive 10, 20, or 30 micrograms.kg-1 (Groups A, B, and C, respectively) of preservative-free morphine administered intrathecally by the surgeon after dural closure. Postoperatively, vital signs, pulse oximetry, and pain intensity scores were recorded hourly for 24 hr. Supplemental intravenous morphine was administered postoperatively according to a predetermined schedule based on pain scores. There was considerable individual variability in the time to initial morphine dosing and cumulative supplemental morphine dose. Time to first supplemental morphine dose was not different between groups. When compared to Groups A and B, cumulative 6-hr supplemental morphine dose was significantly lower in Group C (38.6 +/- 47 micrograms versus 79.1 +/- 74 and 189.6 +/- 126 for Groups A and B, respectively). By 12 hr, cumulative supplemental morphine dose was similar in Groups A and C. Group B consistently had a higher supplemental dose requirement than Groups A and C at 6, 12, and 18 hr. By 24 hr, there was no difference in cumulative dose among groups. Postoperative pain scores and the incidence of respiratory events, nausea, vomiting and pruritus were comparable among groups. These data suggest that intrathecal morphine at 30 micrograms.kg-1 provides the most intense analgesia at 6 hr following selective dorsal root rhizotomy, but was otherwise comparable to the 10 micrograms.kg-1 dose.

Analgesics, Opioid↗
PubMed1996

Sigma receptor activation does not mediate fentanyl-induced attenuation of muscarinic coronary contraction.

Our overall goal was to investigate the mechanism by which fentanyl attenuates acetylcholine-induced contraction in porcine coronary artery. We tested the hypothesis that fentanyl attenuates muscarinic coronary contraction via sigma receptor activation. Left coronary artery vascular rings were isolated from porcine hearts and were suspended in organ chambers for isometric tension recording. In untreated coronary vascular rings, acetylcholine administration resulted in dose-dependent contraction. Fentanyl attenuated acetylcholine-induced contraction. The sigma ligands--(+)-pentazocine, (+)-cyclazocine, haloperidol, and 1,3-di-o-tolylguanidine--also inhibited acetylcholine-induced contraction. In contrast, the selective sigma ligand, (+)-3-(3-hydroxyphenyl)-N-(1-propyl) piperidine failed to have an inhibitory effect on acetylcholine-induced contraction. Moreover, metaphit (1-[1(3-isothiocyanatophenyl)cyclohexyl]piperidine), which causes irreversible acylation of sigma receptors, only inhibited acetylcholine-induced contraction when it was present in the organ chamber. We also assessed the effects of inhibiting various points in the signal transduction pathway distal to naloxone-sensitive opioid receptor activation on acetylcholine-induced contraction. Selective (glybenclamide) and nonselective (tetraethylammonium) K(+)-channel inhibition, guanosine triphosphate-binding protein inactivation (pertussis toxin), and Type 1 and Type 2 dopamine receptor inhibition all failed to alter the attenuating effect of fentanyl on acetylcholine-induced contraction. Thus, neither sigma or opioid receptor activation is a prerequisite for fentanyl-induced inhibition of muscarinic coronary contraction.

Acetylcholine↗
PubMed1996

Effect of cranial surgery and brain tumor size on emergence from anesthesia.

BACKGROUND: Knowing which neurosurgical patients are at risk for delayed awakening may lead to better utilization of intensive care resources and avoid the risk and cost of pharmacologic reversal and diagnostic tests. METHODS: The authors compared anesthetic emergence from complex spinal surgery (spine; n = 47) with that from craniotomy for supratentorial nonfrontal (n = 22), frontal (n = 34), or posterior fossa tumor (n = 28). A further comparison involved patients with small versus large (diameter > 30 mm, mass effect) tumors. The standardized anesthetic regimen consisted of induction with 2-4 mg/kg-1 thiopental and 1-2 micrograms/kg-1 sufentanil, followed by maintenance with nitrous oxide, 0.2-0.5 micrograms.kg-1.h-1 sufentanil and < or = 0.5% isoflurane. Sufentanil administration was terminated on dural or spinal muscle closure, isoflurane during skin closure, and nitrous oxide during dressing application. After discontinuing nitrous oxide, a minineurologic examination was performed every 15 min for 1 h, then hourly for 4 h and at 24 h. RESULTS: Craniotomy patients performed less well than spinal surgery patients on the minineurologic examination 15 and 30 min after discontinuing nitrous oxide. At 15 min, fewer patients with large (vs. small) tumors were oriented to time (58% vs. 87%; P < 0.01) or place (67% vs. 90%; P < 0.01). Forty-two percent of patients with large tumors still had an abnormal minineurologic examination score versus 15% of patients with small tumors. At 30 min, these values were 28% and 8%, respectively (P < 0.05). Seventy-one percent of patients with large tumors were oriented to time compared to 97% for small lesions (P < 0.01). Emergence from anesthesia was similar for spinal surgery patients and patients with small brain tumors. CONCLUSION: Patients undergoing craniotomy for large intracranial mass lesions awaken more slowly than patients after spinal surgery or craniotomy for small brain tumor.

Anesthesia↗
PubMed1995

Side effects of mild hypothermia.

Mild hypothermia is increasingly touted as a low risk clinical measure in brain protection. This article reviews potential adverse effects of mild hypothermia by organ system and suggests a risk assessment framework for clinical decision making.

Blood Coagulation↗
PubMed1994

Assessment of the efficacy and safety of three dose levels of cetirizine given once daily in children with perennial allergic rhinitis.

The present study compared the efficacy and safety of three dose levels of cetirizine (2.5, 5, and 10 mg) once a day with placebo over 14 days in 6-12-year-old children with perennial allergic rhinitis. The design was a double-blind, randomized, multicenter, parallel-group study. Five symptoms (sneezing, nasal discharge, nasal obstruction, nasal pruritus, and ocular pruritus) were rated according to severity by investigators at the visits and daily by patients. Eighty-three patients were randomized to placebo, 84 to 2.5 mg cetirizine, 85 to 5 mg cetirizine, and 76 to 10 mg cetirizine. Groups were comparable at inclusion. The primary efficacy variable was the percentage of days with no or only mild symptoms: at all doses, cetirizine appeared to be more effective than placebo, but a significant difference was reached only in the 10-mg group (difference in medians of 22%; P = 0.016). The test of linearity was significant (P = 0.026) for the percentage of asymptomatic days. The investigators' assessments at each visit scored the symptoms in the placebo group higher, i.e., more severe, than in the active groups, the 10-mg dose causing the greatest reduction in symptoms. Adverse events were infrequent and generally mild or moderate in severity. It was concluded that cetirizine at a 10-mg, once daily dose could be used to treat effectively 6-12-year-old children with perennial allergic rhinitis.

Cetirizine↗
PubMed1994

Intracranial hypertension after resection of cerebral arteriovenous malformations. Predisposing factors and management strategy.

BACKGROUND AND PURPOSE: Surgical excision of cerebral arteriovenous malformations (AVMs) may be complicated by postoperative breakthrough edema and hemorrhage and by intracranial hypertension. Embolization, staged resection, and meticulous surgical technique have decreased but not completely eliminated this complication. In this study we prospectively assess the prevalence of intracranial hypertension after excision of cerebral AVMs, examine factors predisposing to this complication, and document the outcome of aggressive monitoring and treatment of elevated intracranial pressure (ICP). METHODS: During a 4-year period at a single institution, 32 consecutive patients with cerebral AVMs underwent surgical excision after staged embolization. All patients underwent postoperative monitoring of ICP and a uniform management protocol of intracranial hypertension. RESULTS: Intractable intracranial hypertension was encountered after resection of 9 of 32 cerebral AVMs, including 3 of 20 (15%) AVMs 6 cm or less in maximum diameter and 6 of 12 (50%) AVMs greater than 6 cm in maximum diameter. This complication occurred in 5 of 10 (50%) lesions located in distal or border-zone locations, in 4 of 9 (44%) AVMs arising directly off proximal cerebral arteries, and in none of 13 AVMs in other locations. Preoperative single-photon emission-computed tomography perfusion scans were performed in 17 patients and demonstrated parenchymal hypoperfusion beyond the AVM nidus in 5 of 10 AVMs 6 cm or less in maximum diameter, none of which manifested postoperative intractable ICP. Hypoperfusion was observed on single-photon emission-computed tomography in 7 of 7 AVMs greater than 6 cm that were studied by this modality, and intractable ICP was observed postoperatively in 5 of these cases despite preoperative staged embolization in every case. Patients with symptomatic intractable ICP were treated with intravenous short-acting barbiturates under a strict critical care protocol. There was no instance of uncontrollable intracranial hypertension or break-through edema while on barbiturate therapy. There was no permanent morbidity related to this treatment and no mortality or new disability morbidity in this series. CONCLUSIONS: We conclude that intractable intracranial hypertension remains a common complication after resection of a subgroup of cerebral AVMs despite preoperative embolization, modern neuroanesthesia and critical care management, and microsurgical technique. A proactive management protocol aimed at ICP control is safe and effective in the management of this complication.

Barbiturates↗