Ueber Dr. A. Classen's „Beitrag zur physiologischen Optik”

Ohne ZusammenfassungSiehe dies. Archiv Bd. XXV. S. 1.     

The effect of arteriovenous malformation resection on cerebrovascular reactivity to carbon dioxide

To investigate the cerebral hemodynamic changes associated with obliteration of arteriovenous malformations (AVMs), we studied 26 patients undergoing total microsurgical AVM resection during isoflurane and N2/O2 anesthesia. Detectors were placed 5 to 6 cm from the margin of the lesion and in a homologous contralateral position. Cerebral blood flow (CBF) was measured using the intravenous xenon-133 technique before and after AVM resection, during both hypocapnia and normocapnia at each stage. Intraoperative changes in CBF were related to a risk score system based on the patient's history and preoperative angiograms. Seven otherwise healthy patients undergoing spinal surgery were studied to control for anesthetic effects. Patient demographic and clinical data for the AVM group conformed to the expected strata of a large AVM population. The CBF increased after excision (22 +/- 1 ml/100 g/min before excision to 30 +/- 2 ml/100 g/min after excision; mean +/- SE, n = 25, P less than 0.002) without a hemispheric difference. CO2 reactivity increased slightly after excision (4.2 +/- 0.3% change/mm Hg before excision to 4.7 +/- 0.3% change/mm Hg after excision; n = 14, P less than 0.02). The baseline CBF and CO2 reactivity were not different from the control group. There was a weak correlation between the risk score and the percentage of change in the ipsilateral CBF, with a trend for the patients with the lowest risk to have the lowest CBF changes after resection. There was no relationship between CO2 reactivity and risk grade. None of the patients awoke from anesthesia with unexpected neurological deficits. The highest CBF increases were associated with postoperative brain swelling in one patient and fatal intracerebral hemorrhage in another. Both patients had normal CO2 reactivity before excision. One patient suffered postoperative intracerebral hemorrhage, attributable to technical problems, and had no increase in CBF. We conclude that, with an acute increase in the arteriovenous pressure gradient (and cerebral perfusion pressure) that results from shunt obliteration, there is an immediate global effect of AVM resection to increase CBF. Cerebrovascular reactivity to CO2 remains intact both before and after excision.     

Macrophages and translymphatic absorption represent the first line of host defense of the peritoneal cavity

To quantitate the host defenses of the rat peritoneal cavity, nonviable radiolabeled Escherichia coli were injected intraperitoneally and clearance, leukocyte influx, and phagocytosis were examined. Macrophages (MCs) were present initially and remained relatively constant in number. The polymorphonuclear leukocyte (PMN) response began at one to two hours and was maximal at 24 to 72 hours. A previously unidentified inoculum-dependent PMN response was defined. Clearance and phagocytosis were extremely rapid, and few (less than 3%) free bacteria were present after two hours. Phagocytic activity of MCs and PMNs was identical, but MCs were numerically predominant initially and thus accounted for the majority of early phagocytosis. Thus, MC phagocytosis and clearance represent the primary line of host peritoneal defenses. We hypothesize that the subsequent inoculum-dependent PMN response may have evolved to cope with those larger inocula for which this initial response is inadequate.     

Inhibition of in Vitro Generation of Cytotoxicity Against Tumor Cells by Monoclonal Antibody to Thy-1

The Thy-1 molecule on murine T lymphocytes has been suggested to play a role in cellular activation events leading to a variety of immunologic functions. We present evidence that this molecule may be involved in signals leading to the in vitro generation of cytotoxic T cells against several tumor cell lines used as stimulators in mixed tumor-lymphocyte culture. The presence of monoclonal antibody against a polymorphic determinant on the Thy-1 molecule markedly reduced the generation of cytotoxicity after three days of culture of murine splenocytes with stimulator tumor cells bearing low levels of Ia antigen. In contrast, no effect was seen when the stimulators were either allogeneic splenocytes, or a tumor cell line expressing large amounts of Ia. These results suggest that the Thy-1 molecule is critically involved in events leading to the generation of cytotoxic effectors under some, but not all conditions.     

Tacrolimus with Mycophenolate Mofetil (MMF) or Sirolimus vs. Cyclosporine with MMF in Cardiac Transplant Patients: 1-Year Report

The most advantageous combination of immunosuppressive agents for cardiac transplant recipients has not yet been established. Between November 2001 and June 2003, 343 de novo cardiac transplant recipients were randomized to receive steroids and either tacrolimus (TAC) + sirolimus (SRL), TAC + mycophenolate mofetil (MMF) or cyclosporine (CYA) + MMF. Antilymphocyte induction therapy was allowed for up to 5 days. The primary endpoint of >/=3A rejection or hemodynamic compromise rejection requiring treatment showed no significant difference at 6 months (TAC/MMF 22.4%, TAC/SRL 24.3%, CYA/MMF 31.6%, p = 0.271) and 1 year (p = 0.056), but it was significantly lower in the TAC/MMF group when compared only to the CYA/MMF group at 1 year (23.4% vs. 36.8%; p = 0.029). Differences in the incidence of any treated rejection were significant (TAC/SRL = 35%, TAC/MMF = 42%, CYA/MMF = 59%; p < 0.001), as were median levels of serum creatinine (TAC/SRL = 1.5 mg/dL, TAC/MMF = 1.3 mg/dL, CYA/MMF = 1.5 mg/dL; p = 0.032) and triglycerides (TAC/SRL = 162 mg/dL, TAC/MMF = 126 mg/dL, CYA/MMF = 154 mg/dL; p = 0.028). The TAC/SRL group encountered fewer viral infections but more fungal infections and impaired wound healing. These secondary endpoints suggest that the TAC/MMF combination appears to offer more advantages than TAC/SRL or CYA/MMF in cardiac transplant patients, including fewer >/=3A rejections or hemodynamic compromise rejections and an improved side-effect profile.     

Pyogenic infections of the central nervous system secondary to dental affections—a report of six cases

Pyogenic infections of the central nervous system of dental origin are quite uncommon in industrialized countries. We report six cases with intracerebral (n=4) and intraspinal (n=2) infections treated in our hospital. The microbial pathogen was successfully isolated in all patients. Fusobacterium nucleatum as well as Streptococcus species were found in three cases. Bacillus species were identified in two patients. Actinomyces was the etiologic agent in one case. All patients suffered from dental pathologies, so that after clinical and radiological exclusion of other sources an oral focus was presumed. Therapeutic management consisted of an operative procedure in order to obtain decompression, as well as evacuation of the pus on the one hand, followed by targeted antibiotics on the other. Clinical improvement was achieved in all patients, with one patient lost to follow-up. On magnetic resonance tomography, the inflammatory changes also disappeared in all cases. We recommend that oral infection with recurrent bacteraemia should always be considered in the pathogenesis of the so-called “cryptic” intracerebral and intraspinal infections.     

Initial steps taken by nine primary care practices to implement alcohol screening guidelines with hypertensive patients: the AA-TRIP project.

Many medical conditions are caused or exacerbated by heavy drinking, necessitating alcohol screening and discussion in primary care practices. This is particularly true of hypertension, the most common primary diagnosis in the United States, which has been linked to the regular consumption of 3 or more standard alcoholic beverages a day. The Accelerating Alcohol Screening-Translating Research into Practice (AA-TRIP) project was designed to improve detection and management of alcohol problems in primary care patients with hypertension. Medical providers are being trained using the Practice Partner Research Network's- Translating Research into Practice (PPRNet-TRIP) quality improvement model. This includes a multi-method intervention (electronic medical records, on-site academic detailing, practice feedback reports and annual network meetings) to help practices increase adherence to clinical guidelines. Qualitative analyses of initial steps taken by nine primary care practices toward the routine implementation of alcohol screening guidelines are presented. Organizational factors and provider and patient characteristics all influenced the method and consistency of alcohol screening and intervention. Perceived time constraints, patient sensitivity to questions about alcohol, and possible stigma associated with a diagnosis of alcoholism were also relevant barriers requiring problem solving.