Time-course relationship between cerebrospinal fluid and serum concentrations of midazolam and albumin in patients with cardiac arrest undergoing targeted temperature management

AIM

To understand the serum and cerebrospinal fluid (CSF) distribution of midazolam is important for proper timing of neurological prognostication of targeted temperature management(TTM) patients. Midazolam binds extensively to albumin in serum although non protein bound form exist in CSF. We investigated the time-course of CSF, serum concentrations of midazolam and albumin in patients with cardiac arrest who underwent TTM.

METHODS

This prospective, single-center, observational study was conducted between May 2020 and April 2022. Midazolam and albumin concentrations in CSF and serum were quantified 0, 24, 48, and 72 h after the return of spontaneous circulation for comparison between the good (Cerebral Performance Category (CPC) 1 and 2) and poor (CPC 3, 4, and 5) neurologic outcome groups. The CSF/serum (C/S) ratios of midazolam and albumin concentrations were determined, along with their correlation coefficients.

RESULTS

Of the 19 enrolled patients, 13 experienced poor outcomes. At 0 h, serum midazolam concentrations were the lowest, whereas serum albumin levels were the highest; in the CSF, the concentrations of both peaked at 24 h. There were no significant inter-group differences in midazolam concentrations in CSF or serum. The C/S ratios of midazolam and albumin significantly differed between the groups. Moderate to strong positive correlations were observed between the midazolam and albumin C/S ratios.

CONCLUSION

In CSF, midazolam and albumin concentrations peaked 24 h post-cardiac arrest. Midazolam and albumin C/S ratios were significantly higher in the poor outcome group and positively correlated with each other, suggesting blood-brain barrier disruption 24 h post-cardiac arrest.

Serum and cerebrospinal fluid concentrations of midazolam after epidural administration in dogs

The epidural administration of midazolam has analgesic effects that might be mediated by gamma-aminobutyric acid type A receptors in the spinal cord. In this study, we examined both serum and cerebrospinal fluid (CSF) concentrations of midazolam after epidural administration to investigate the possibility of midazolam entering CSF directly from the epidural space. Five male mongrel dogs had catheters inserted in a femoral artery, the epidural space at L3-4, and the intrathecal space at the atlanto-occipital region under general anesthesia. Midazolam 1 mg/kg was epidurally administered, and arterial blood and CSF samples were collected until 240 min after the midazolam administration to measure midazolam concentration. Serum midazolam concentration increased and reached a peak at 30 min after the administration (224.8 +/- 30.5 ng/mL) and then decreased to 25.8 +/- 6.0 ng/mL at 240 min. Midazolam concentration in the CSF was less than the detection limit at 5 min, reached a peak at 30 min after the administration (7.2 +/- 4.7 ng/mL), and decreased to 3.6 +/- 3.3 ng/mL at 240 min. In conclusion, epidurally administered midazolam enters CSF, but CSF concentrations are only 3% of those in the systemic circulation.

IMPLICATIONS

Midazolam, which has spinally mediated analgesic potency, was epidurally administered in dogs, and serum and cerebrospinal fluid concentrations were measured. Epidurally administered midazolam enters the cerebrospinal fluid, but concentrations are only 3% of those in the systemic circulation.

Intratumoral doxorubicin in patients with malignant brain gliomas

The objective of the study was to evaluate the safety and therapeutic efficacy of intralesional administration of doxorubicin in brain gliomas. Ten patients with recurrent grade III or IV glioma were enrolled in the study, after the second operation. All patients had not responded to radiation therapy. Chemotherapy was administered directly in the tumor through an Ommaya pump placed in the site of disease at the time of craniotomy. Doxorubicin 0.5 mg was administered in the Ommaya reservoir every 24 hours on days 1 to 10. Patients were evaluated at 6- to 8-week intervals until tumor progression and death. All patients were evaluated for response. Six of 10 patients had clinical improvement lasting from 12 to 73 weeks. Objective radiologic response was observed in 5 of 10 (50%) patients. One patient achieved complete response with time to disease progression of 119 weeks, and 4 patients had a partial response (duration 14-39 weeks) with 25% or more reduction of tumor volume on computed tomography scan compared with pretreatment measurements. Time to disease progression in patients who responded after the intratumoral chemotherapy was 39.83 +/- 40.5 weeks. One additional patient had stable disease for a duration of 12 weeks. The median survival of the patients with response was 55.17 +/- 54.22 weeks (range: 21-164 weeks), whereas survival of those who did not respond was 17.0 +/- 12.36 weeks (range: 8-35) (Mann Whitney U test: z = -2.13, p = 0.033). The median survival of all 10 patients was 39.9 +/- 45.52 weeks (range: 8-73 weeks). Bifrontal headache was reported in 4 of 10 patients immediately after the administration of doxorubicin. There were no other clinically significant adverse reactions either in the brain or systematically. Intralesional administration of doxorubicin appears to be a safe and effective treatment and should be further explored in the management of brain gliomas resistant to conventional forms of treatment.

Response of short-term cultures derived from human malignant glioma to aziridinylbenzoquinone, etoposide and doxorubicin: an in vitro phase II trial

The relative resistance of malignant glioma to chemotherapy makes the identification of new cytotoxic drugs critically important. The use of short-term cultures derived from these tumors to screen drugs at doses that can be attained within human intracranial tumors provides a model system that should be capable of identifying effective drugs suitable for clinical evaluation. The sensitivity of a panel of short-term cultures derived from 22 malignant astrocytoma and four malignant oligodendroglioma was assessed to aziridinylbenzoquinone (AZQ), etoposide and doxorubicin (DOX) using a [(35)S] methione uptake assay. The ID(50) of each culture was compared to the levels of drug which could be achieved in the tumor using standard doses. There was marked heterogeneity between cultures in response to each drug. Whilst there was no evidence that cultures derived from grade III astrocytoma were more sensitive to any of the drugs than cultures derived from grade IV astrocytoma, cultures derived from oligodendroglioma tended to be more sensitive to the alkylating agent AZQ, but not to either of the other drugs. The sensitivity of these short-term cultures at concentrations that can be achieved in situ corresponded well with the clinical efficacy of AZQ and etoposide. Although DOX appeared to be toxic to human gliomas cells in vitro, its limited penetration into the intact brain would seem to preclude its use i.v., but it is likely to be effective if local drug delivery techniques could be employed. The study suggests that short-term cultures derived from malignant glioma should be used to screen investigational agents for potential clinical efficacy.

Quantification and pharmacokinetics of blood-brain barrier disruption in humans

Hyperosmolar blood-brain barrier disruption (HBBBD), produced by infusion of mannitol into the cerebral arteries, has been used in the treatment of brain tumors to increase drug delivery to tumor and adjacent brain. However, the efficacy of HBBBD in brain tumor therapy has been controversial. The goal of this study was to measure changes in vascular permeability after HBBBD in patients with malignant brain tumors. The permeability (K1) of tumor and normal brain blood vessels was measured using rubidium-82 and positron emission tomography before and repeatedly at 8- to 15-minute intervals after HBBBD. Eighteen studies were performed in 13 patients, eight with glioblastoma multiforme and five with anaplastic astrocytoma. The HBBBD increased K1 in all patients. Baseline K1 values were 2.1 +/- 1.4 and 34.1 +/- 22.1 microl/minute/ml (+/- standard deviation) for brain and tumor, respectively. The peak absolute increases in K1 following HBBBD were 20.8 +/- 11.7 and 19.7 +/- 10.7 microl/minute/ml for brain and tumor, corresponding to percentage increases of approximately 1000% in brain and approximately 60% in tumor. The halftimes for return of K1 to near baseline for brain and tumor were 8.1 +/- 3.8 and 4.2 +/- 1.2 minutes, respectively. Simulations of the effects of HBBBD made using a very simple model with intraarterial methotrexate, which is exemplary of drugs with low permeability, indicate that 1) total exposure of the brain and tumor to methotrexate, as measured by the methotrexate concentration-time integral (or area under the curve), would increase with decreasing infusion duration and would be enhanced by 130% to 200% and by 7% to 16%, respectively, compared to intraarterial infusion of methotrexate alone; and 2) exposure time at concentrations above 1 microM, the minimal concentration required for the effects of methotrexate, would not be enhanced in tumor and would be enhanced by only 10% in brain. Hyperosmolar blood-brain barrier disruption transiently increases delivery of water-soluble compounds to normal brain and brain tumors. Most of the enhancement of exposure results from trapping the drug within the blood-brain barrier, an effect of the very transient alteration of the blood-brain barrier by HBBBD. Delivery is most effective when a drug is administered within 5 to 10 minutes after disruption. However, the increased exposure and exposure time that occur with methotrexate, the permeability of which is among the lowest of the agents currently used clinically, are limited and the disproportionate increase in brain exposure, compared to tumor exposure, may alter the therapeutic index of many drugs.

Doxorubicin encapsulated in sterically stabilized liposomes for the treatment of a brain tumor model: biodistribution and therapeutic efficacy

Anthracyclines entrapped in small-sized, sterically stabilized liposomes have the advantage of long circulation time, reduced systemic toxicity, increased uptake into systemic tumors, and gradual release of their payload. To date, there is no information on the behavior of these liposomes in brain tumors. The objective of this study was to compare the biodistribution and clinical efficacy of free doxorubicin (F-DOX) and stealth liposome-encapsulated DOX (SL-DOX) in a secondary brain tumor model. Nine days after tumor inoculation Fischer rats with a right parietal malignant sarcoma received an intravenous dose of 6 mg/kg of either F-DOX or SL-DOX for evaluation of drug biodistribution. For therapeutic trials a single dose of 8 mg/kg was given 6 or 11 days after tumor induction, or alternatively, weekly doses (5 mg/kg) were given on Days 6, 13, and 20. Liposome-encapsulated DOX was slowly cleared from plasma with a t1/2 of 35 hours. Free-DOX maximum tumor drug levels reached a mean value of 0.8 microgram/g and were identical in the adjacent brain and contralateral hemisphere. In contrast, SL-DOX tumor levels were 14-fold higher at their peak levels at 48 hours, declining to ninefold increased levels at 120 hours. A gradual increase in drug levels in the brain adjacent to tumor was noted between 72 and 120 hours (up to 4 micrograms/g). High-performance liquid chromatography analysis identified a small amount of aglycone metabolites within the tumor mass from 96 hours and beyond, after SL-DOX injection. Cerebrospinal fluid levels were barely detectable in tumor-bearing rats treated with F-DOX up to 120 hours after drug injection (< or = 0.05 microgram/ml), whereas the levels found after SL-DOX were 10- to 30-fold higher. An F-DOX single-dose treatment given 6 days after tumor inoculation increased the rats' life span (ILS) by 135% over controls (p < 0.05) but was not effective if given on Day 11. In contrast, SL-DOX treatment resulted in an ILS of 168% (p < 0.0003) with no difference when given after 6 or 11 days. Treatment with three weekly doses of SL-DOX produced an ILS of 189% compared to 126% by F-DOX (p < 0.0002). The authors conclude that the use of long-circulating liposomes as cytotoxic drug carriers in brain tumor results in enhanced drug exposure and improved therapeutic activity, with equal effectiveness against early small- and large-sized brain tumors.

Results of a randomized trial comparing intra-arterial cisplatin and intravenous PCNU for the treatment of primary brain tumors in adults: Brain Tumor Cooperative Group trial 8420A

PURPOSE

To test the efficacy of intra-arterial (IA) cisplatin versus intravenous (IV) PCNU for treating primary brain tumors, in a randomized trial (Brain Tumor Cooperative Group [BTCG] Trial 8420A).

METHODS

311 adult patients (ages 19-79 years; median 45) with supratentorial tumors (confirmed histologically) were randomized by nine participating institutions. Patients were required to have completed radiotherapy (4500-6020 cGy to the tumor bed) before randomization. Patients were stratified as either nonprogressive (clinically and radiologically stable) or progressive. Results were analyzed for the 311 patients in the randomized population (RP), and for the 281 patients in the Valid Study Group (VSG) meeting protocol eligibility requirements. 56% of patients in the VSG had glioblastoma multiforme, 33% had other malignant glioma, and 11% had low-grade glioma. 64% were stratified as progressive. 12% had received prior chemotherapy.

RESULTS

The group randomized to PCNU had the longer survival (p = 0.06 for the RP, p = 0.07 for the VSG). In the VSG, median survival was 10 months for the cisplatin group, 13 months for the PCNU group. The difference between treatment groups was significant (p < or = 0.02) when adjusted for important prognostic factors. PCNU lead to greater hematotoxicity; cisplatin lead to greater renal toxicity and some ototoxicity. Some cisplatin patients experienced complications associated with IA administration, including six cases of encephalopathy.

CONCLUSION

The trial showed a survival advantage to the group randomized to PCNU, although the difference was modest. Coupled with previous BTCG results, these trails suggest that PCNU is an active drug for brain tumors.

Brachytherapy for recurrent single brain metastasis

Of 112 stereotactic high-activity iodine-125 implants for malignant brain tumors done as of July 1, 1994, ten have been done for recurrent single brain metastasis and constitute the study group described herein. All patients had initially undergone craniotomy for tumor resection followed by fractionated external beam whole brain radiation and recurred at the same site in the brain. The interval between initial cancer therapy and occurrence of the brain metastasis was 13-156 weeks (median: 63 weeks). The interval between initial treatment of the brain metastasis and its recurrence treated with brachytherapy was 13-69 weeks (median: 35 weeks). Minimum brachytherapy dose administered was 70 Gy at a median dose rate of 67 cGy/hour. Eight patients have died. Two died suddenly at 2 and 13 weeks post-implant of presumed pulmonary embolus. Five died of recurrence of the brain metastasis at 20, 39, 52, 103, and 143 weeks post-implant, and one died of systemic metastases at 40 weeks post-implant. Two patients remain alive 183 and 324 weeks post-implant. High-activity iodine-125 brachytherapy appears to be of benefit for selected patients with recurrent single brain metastasis but larger, and preferably randomized studies are needed.

Efficacy of direct intratumoral therapy with targeted protein toxins for solid human gliomas in nude mice

Targeted protein toxins are a new class of reagents with the potential for great tumor selectivity and cytotoxic potency. Two such compounds were studied: 1) Tf-CRM107, a conjugate of human transferrin (Tf) and diphtheria toxin with a point mutation (CRM107); and 2) 454A12-rRA, a conjugate of a monoclonal antibody (454A12) to the human Tf receptor and recombinant ricin A chain (rRA). Both compounds are potent and specific in killing human glioblastoma cell lines in vitro. The authors investigated the activity of these reagents administered intratumorally against solid U251 MG human gliomas in vivo. Nude mice with established U251 MG flank tumors (0.5 to 1.0 cm in diameter) were randomly assigned to be treated with 100-microliters intratumoral injections of Tf-CRM107 (10 micrograms) or 454A12-rRA (10 micrograms), equimolar doses of CRM107 (4.3 micrograms), 454A12 antibody (7.5 micrograms), or rRA (1.5 micrograms), or phosphate-buffered saline (PBS) every 2 days for a total of four doses. Tumor volume and animal weight were assessed by a blinded observer before each treatment and biweekly for 30 days after initiating therapy. With Tf-CRM107 administration, tumor regression of greater than 95% occurred by Day 14 (p < 0.01) and tumors did not recur by Day 30. Treatment with 454A12-rRA caused a 30% decrease in tumor volume by Day 14 (p < 0.01). Treatment with equimolar doses of the unconjugated targeted protein toxin components CRM107, 454A12, or rRA caused significant U251 MG tumor growth inhibition, but the effects were less potent than the antitumor effects of the conjugates. This study also characterized the dose-response effect of Tf-CRM107 on tumor growth and tumor weight on Day 30. Nude mice with established U251 MG flank tumors (0.5 to 1.0 cm in diameter) were treated with 100-microliters intratumoral injections of 10, 1.0, or 0.1 microgram of Tf-CRM107 or PBS every 2 days for a total of four doses. All three doses of Tf-CRM107 significantly inhibited tumor growth by Day 14 (p < 0.01) and at Day 30 (p < 0.05), with a significant dose-response relationship. This study demonstrated in vivo efficacy of the targeted toxins Tf-CRM107 and 454A12-rRA against a human glioma. With intratumoral administration, the effect of Tf-CRM107 was tumor-specific and in some animals curative. Regional therapy with these potent tumor-specific agents using direct intratumoral infusion should limit systemic toxicity and may be efficacious against brain tumors.

Vancomycin administration into the cerebrospinal fluid: a review

OBJECTIVE

To discuss administering vancomycin directly into the cerebrospinal fluid (CSF) to treat serious central nervous system (CNS) infections.

DATA SOURCES

References were obtained through an online search of MEDLINE, limited to material published in English. In addition, information was extracted from clinical trials, review articles, abstracts, and textbooks.

STUDY SELECTION

Systematic evaluation of this topic in humans has not been done in a prospective manner. Related research articles describing the pathophysiology of CNS infections, intrathecal drug administration, and case reports of CSF vancomycin administration were reviewed.

DATA EXTRACTION

Case reports regarding CSF vancomycin dosing were evaluated and included: drug dosing, infecting organism, infectious disease state, infectious outcome, CSF dynamics/flow abnormalities, methods of drug administration, drug monitoring, and toxicities.

DATA SYNTHESIS

The results of this review are based on qualitative evaluations of anecdotal case reports and a basic understanding of intrathecal and intraventricular drug dosing principles. CSF administration of vancomycin is an effective means of bypassing the blood-brain barrier to achieve greater drug concentrations within the CSF. Current limitations to the CSF administration of vancomycin include a lack of data describing its safety, efficacy, and pharmacokinetics.

CONCLUSIONS

CNS infections may require the CSF administration of vancomycin for successful eradication. Recommendations for dosing in the literature vary. Because of the potential toxicities associated with elevated CSF concentrations of vancomycin, dosing should be conservative.

Treatment of brain metastases from bladder cancer

The records of 28 patients with transitional cell cancer who had brain metastases were retrospectively reviewed. Data from 19 patients were considered suitable for analysis and were included in this study. One patient was treated with surgery alone, 10 with radiation alone and 7 with radiation and surgery, while 1 received no treatment. Mean and median survival times, respectively, were 57 and 42 months from the initial diagnosis, and 11 and 4 months from diagnosis of central nervous system metastases. Patients treated with surgery and radiation demonstrated a mean survival time of 19 months compared to 6 months for patients treated with radiation alone (p = 0.03). There were 2 long-term survivors in the combined modality group at 50 and at 12 months. Enthusiasm for combined modality treatment should be tempered by the fact that selection bias favored the combined modality group; 13 patients with single lesions demonstrated a mean survival of 14 months compared to 3 months for 6 patients with multiple lesions (p = 0.009) and only patients with solitary lesions underwent surgical resection. Brain metastases have an ominous prognosis in patients with bladder cancer primaries. Considering the sum of the retrospective and prospective reports, we recommend that patients with solitary brain lesions and good performance status be aggressively managed with surgical resection and postoperative radiation therapy.

The intracerebral distribution of BCNU delivered by surgically implanted biodegradable polymers

The local concentration and distribution of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) within normal brain tissue were studied following surgical implantation of biodegradable polymer containing BCNU in New Zealand White rabbits. Cylindrical discs of poly(bis(p-carboxyphenoxy)-propane:sebacic acid) copolymer in a 20:80 formulation were made containing [3H]-inulin or [3H]-BCNU labeled in the methylene hydrogens of the chloroethyl groups. These were implanted in the brains of 56 New Zealand White rabbits. The animals were sacrificed 3, 7, 14, or 21 days later and the brains were rapidly removed, frozen, and prepared for quantitative autoradiography. Autoradiographs from coronal sections bisecting the polymer were analyzed to determine both the proportion of the brain section exposed to the tracer and the local drug concentrations as a function of distance from the polymer. Tritiated BCNU was also injected directly into the brains of eight additional rabbits, and local brain concentrations were studied over time. The results of this study demonstrate that approximately 50% of the area of the brain sections was exposed to radiolabeled compound 3 days after BCNU-polymer implantation, 15% at 7 days, and less than 10% at 14 and 21 days. Polymer discs containing 600 micrograms BCNU generated 6 mM concentrations of BCNU in brain tissue 10 mm from the polymer at 3 and 7 days. Pharmacological studies demonstrated that approximately 25% of the tritium label was associated with intact BCNU 3 days following polymer implantation. Radiolabeled inulin delivered by polymer remained dispersed throughout the ipsilateral hemisphere for 14 days. Direct injection of [3H]-BCNU into brain parenchyma resulted in widely distributed tracer at 1 and 3 hours with rapid disappearance thereafter. It is concluded that local delivery of BCNU to brain tissue with this polymeric drug delivery system results in sustained high local concentrations of BCNU which may be of value in the treatment of patients with brain tumors.

Interstitial chemotherapy for brain tumors: review

An extensive effort to search for curative chemotherapeutic approaches has found no 'breakthrough' in management of patients with malignant brain tumors. Despite the trials with new agents or protocols of multiple agents, systemic chemotherapy has failed to provide reliable clinical response. Interstitial chemotherapy has been practiced for malignant brain tumors with administering chemotherapeutic compounds directly into the tumor which provide increased and prolonged drug concentration in the tumor, reduction of systemic toxicity and bypassing the blood-brain barrier. These theoretical advantages encourage further pursuing interstitial chemotherapy for patients with malignant brain tumors who would otherwise be always fatal. In this review, the literature has been reviewed to identify methods, toxicity, and efficacy of interstitial chemotherapy. Clinical and experimental data indicate limited toxicity and promising efficacy. Various methods to administer the agents were utilized; intraoperative topical application, local injections through catheters or implantable controlled drug delivery system. Selection of ideal chemotherapeutic agents and development of drug delivery system need further investigations.

Light and electron microscopic observations on the cerebellum of guinea pigs following low-dose methotrexate

The neurotoxicity of single and divided low-dose methotrexate (MTX) and the rescue effect of leucovorin (folic acid) were investigated by light and electron microscopic examination of the cerebellum of Guinea pigs. One group of animals received a single weekly intraperitoneal MTX in a dose of 10 mg/kg, a second received a similar dose divided into three equal fractions, and the third group received MTX rescued with an equal dose of leucovorin. The results showed degeneration of Purkinje cells indicated by shrinkage and distortion of perikarya, dissolution of mitochondrial cristae, and nuclear and nucleolar changes in all groups which received MTX. There was also astrocytic proliferation and perivascular edema. Lesser changes were found in the group which was rescued with leucovorin. The degenerative changes in the cerebellum particularly those of the Purkinje cells explain the neurological signs reported in cancer patients treated with MTX.

Brain biocompatibility of a biodegradable, controlled-release polymer in rats

We report the biocompatibility in the rat brain of a controlled-release, biodegradable polymer, the polyanhydride poly-[bis(p-carboxyphenoxy)propane-sebacic acid] copolymer (PCPP-SA) in a 20:80 formulation. The biodegradable polyanhydride can be used for drug delivery directly into the brain, circumventing the difficulties posed by the blood-brain barrier and avoiding the consequences of having to administer toxic doses systematically to reach therapeutic doses in the central nervous system. The tissue reaction in the presence of PCPP-SA was compared to that seen with other standard neurosurgical implants. Fifty-six adult Sprague-Dawley rats were assigned to one of seven groups and underwent bilateral frontal lobe implantation of PCPP-SA (42 hemispheres), Surgicel (oxidized regenerated cellulose) (35 hemispheres), or Gelfoam (absorbable gelatin sponge) (35 hemispheres). None of the animals showed any behavioral changes or neurological deficits suggestive of either systemic or localized toxicity from the biodegradable polyanhydride, all surviving to the scheduled data of sacrifice. PCPP-SA evoked a well localized inflammatory reaction, comparable to that of Surgicel, which resolved as the PCPP-SA polymer degraded over five weeks. The biodegradable polyanhydride has been shown in this study to be nontoxic and biocompatible in the rat brain, when compared to standard neurosurgical implants.

Clinical pharmacokinetics of nonsteroidal anti-inflammatory drugs in the cerebrospinal fluid

The pharmacokinetics of nonsteroidal anti-inflammatory drugs (NSAIDs) in the cerebrospinal fluid (CSF) is of clinical interest as it may be related to some of their properties and side-effects. Two types of NSAIDs can be described with respect to their concentration and time course in CSF: in the first type, the transfer across the blood-brain barrier seems to be controlled by simple physico-chemical factors. These drugs (oxyphenbutazone, indomethacin, ketoprofen) are characterized by a high lipophilicity. At steady state, their free plasma concentrations correspond to their CSF concentrations. The second group consists of more hydrophilic compounds (salicylates); there is no correlation between plasma concentrations and CSF concentration. Further investigation needs to be carried out on CNS side-effects and the antialgesic activity of salicylates in relation on their CSF distribution.

Preliminary experimental results with the nitrosourea derivative ACNU in the treatment of malignant gliomas

Comparative studies were carried out to evaluate the cytotoxic effectiveness of the nitrosureas ACNU (Nimustine) and BCNU (Carmustine) at equitoxic dose levels in xenografts from two astrocytomas grades III/IV (Li, Re) and one oligodendroglioma grade III (Oe) on nude mice. Growth delay was measured as the endpoint. All tumours were characterized initially and at regular intervals in later passages as to their histomorphologic pattern, expression of glial fibrillary acid protein and DNA-content by means of flow cytometry. These characteristics were shown to be unchanged in our xenografts over more than 27 passages. Growth delays of 18.7 days (ACNU) and 2.4 days (BCNU) for the Li-xenograft (p less than 0.01) were observed at an LD10 for both drugs. For the Re- and Oe-xenografts, growth delays of 18.0 vs. 14.0 days (p less than 0.001) and greater than 27.0 vs. 14.2 days (p less than 0.02) were observed at an equitoxic dose of 33 mg/kg ACNU or BCNU i.p., respectively. These preclinical data suggest a therapeutic advantage with ACNU for these high grade gliomas and should encourage further experimental and clinical investigations.

Neurotoxicity of beta-lactam antibiotics. Experimental kinetic and neurophysiological studies

The neurotoxic potential of intravenous administered benzylpenicillin (BPC) was studied in rabbits with intact blood-CNS barriers and rabbits with experimental E. coli meningitis. At onset of epileptogenic EEG activity or seizures, serum, CSF and brain tissue were collected for assay of BPC. Based on the fact that, in tissues, BPC seems to remain extracellularly, brain concentrations of BPC were expressed as brain tissue fluid (BTF) levels, calculated as 10x the concentration in whole brain tissue. Neurotoxicity could be precipitated in all rabbits. In normal rabbits BTF levels of BPC were considerably higher than those in CSF indicating a better penetration across the blood-brain barrier (BBB). BPC penetrated better to CSF and BTF in meningitic rabbits than in normal controls, suggesting some degree of damage of the BBB concomitant with meningeal inflammation. E. coli meningitis did not increase the neurotoxicity of BPC. In control rabbits the intracisternal injection of saline resulted in some degree of pleocytosis. Unmanipulated animals are therefore preferable as controls. Epileptogenic EEG-changes was the most precise of the two variables used for demonstration of neurotoxicity. EEG-changes were therefore used as neurotoxicity criterion in the following rabbit experiments. To evaluate the effect of uraemia alone and uraemia plus meningitis on the neurotoxity of BPC in rabbits, cephaloridine was used to induce uraemia. Meningitis was induced by intracisternal inoculation of a cephalosporin resistant strain of E. cloacae. Untreated rabbits were used as controls. Uraemia resulted in increased BTF penetration of BPC, possibly explained by permeability changes in the BBB and/or decreased binding of BPC to albumin. Uraemia did not result in increased penetration of BPC into the CSF of non-meningitic rabbits. Uraemic non-meningitic rabbits had the highest BTF levels of BPC at the criterion, indicating that cephaloridine-induced renal failure increased the epileptogenic threshold in these rabbits. The combination of uraemia and meningitis increased the neurotoxicity of BPC since the criterion was reached at considerably lower BTF levels of BPC. Meningitis, either alone or together with uraemia, did not increase the neurotoxicity in comparison to control rabbits. Higher BTF levels of BPC were found in meningitic rabbits than in controls with intact blood-CNS barriers at onset of EEG-changes. In all groups of rabbits there was a pronounced variability of BPC levels in the CSF while the intra-group variations in BTF levels were much smaller. Thus, BTF and not CSF levels were decisive for the neurotoxicity of BPC.(ABSTRACT TRUNCATED AT 400 WORDS)

Prospective randomized cooperative medulloblastoma trial (MED 84) of the International Society of Paediatric Oncology (SIOP) and of the (German) Society of Paediatric Oncology (GPO)

This international, prospective, randomised therapeutic study is based on previous, separate studies of the two societies. The study asks two principal questions: Is it possible to improve the results of therapy by inserting, between surgery and post-operative irradiation, an intensive course of chemotherapy consisting of vincristine, procarbazine and methotrexate, followed by citrovorum factor rescue? In "low risk" patients (i.e. those with macroscopically "complete" resection and absence of metastases at diagnosis), can the radiotherapy to CNS areas outside the primary tumour site be reduced by 10 Gy with the aim of reducing late sequelae of irradiation but without compromising survival results? The study also aims at standardising diagnostic methods, neurosurgical procedure and radiotherapeutic technique employed in this tumour. For statistical reasons, results can only be disclosed after the end of the recruitment phase. It is intended to include approximately 350 patients in the study, which is planned to continue until the end of 1988.

Chemotherapy induces regression of brain metastases in breast carcinoma

This study improves treatment options and ultimately survival by using systemic chemotherapy in brain metastases from breast carcinoma, since most of these patients have disseminated disease and a dismal prognosis when treated by conventional brain irradiation alone. One hundred consecutive patients with symptomatic brain metastases documented by radionuclide and/or computerized tomography scan were treated with systemic chemotherapy. Fifty of 100 patients demonstrated an objective response of brain metastases which was similar for extracranial metastases. There were 10 complete responders (CR), 40 partial responders (PR), 9 stable, and 41 nonresponders. Median duration of remission was 10+ months for CR and 7 months for PR (range, 2-72 months). Primary chemotherapy of brain metastases yielded responses in 27 of 52 patients (52%) treated with Cytoxan (cyclophosphamide) (C), 5-fluorouracil (F) and prednisone (P); 19 of 35 (54%) receiving CFP-methotrexate (M) and vincristine (V); 3 of 7 (43%) treated with MVP, and 1 of 6 (17%) receiving Cytoxan plus Adriamycin (doxorubicin) (CA). Thirteen of 35 patients (37%) who subsequently had relapse of brain metastases were retreated successfully with secondary chemotherapy. The median survival for CR and PR was 39.5 months and 10.5 months, respectively, in contrast with nonresponder patients who had a median survival of 1.5 months. Thirty-one percent of all treated patients survived more than 12 months. These findings suggest that the chemotherapeutic agents used penetrate the blood-brain barrier inducing regression of brain metastases. This approach offers a significant benefit by simultaneously controlling extracranial disease, improving the response and prolonging survival.

A study of intrathecal, cerebrospinal fluid-to-brain exchange

A cerebrospinal fluid (CSF) to brain exchange has been postulated for lipid-soluble and small molecular substances and has led to nearly 100 attempts per year to produce central effects via intrathecal injections. With few exceptions, however, modern neurological practice has avoided this approach because of its demonstrated ineffectiveness and dangers. The practicability of an intrathecal CSF to brain exchange was tested by cisternal infusions of mock CSF at different infusion pressures that might counteract central nervous system intoxications of systemic origin. Those efforts failed in different test situations with each of three barbiturates. Steady state doses at a selected level of barbiturate anesthesia were the same, whether induced by cisternal infusion or intravenously, and this was true for barbiturates of widely different lipid solubility. The cerebral response to pentylenetetrazol was delayed well beyond its rate of response when introduced intravenously. These results suggested that the bulk clearance rate and venous resorption of CSF were sufficient to prevent significant diffusion of the barbiturate or even mock CSF into the brain following intrathecal injection. Because central effects that follow venous resorption may be confused with direct central effects, many previous clinical reports are questioned. Apparent exceptions to the ineffectiveness of intrathecal therapy, such as spinal anesthesia, were discussed in terms of their special local effects. The relative effectiveness of intrathecal agents should be evaluated by comparing maintenance doses for a given central effect, when produced by both intrathecal and i.v. routes. Previous reports on rates of intrathecal infusion, intracranial pressure relationships, and the relative safety of such infusions were confirmed and extended.

Intensive chemotherapy with autologous bone marrow rescue for recurrent malignant gliomas

Eight patients, four male and four female, were treated with high dose chemotherapy followed by bone marrow transplantation. In the first two patients, high dose ACNU was used for the treatment without combination with other drugs. This showed severe side effects such as intratumorous bleeding on the 18th day of treatment in the first case and pulmonary fibrosis on the 35th day of treatment in the second case. Considering these results, we considered another treatment schedule which consisted of high dose ADM (100 mg/m2), VCR (1.5 mg/m2), CDDP (80 mg/m2 X 4) and Ex (800 mg/m2) within seven days. Six patients were treated with this schedule and the results indicated that two patients had a partial response (more than 50% reduction of tumour size measured by CT scan), one had a complete remission (no tumour detected by CT scan), two showed no change and one, progression of the lesion. The patients recovered from the suppression of bone marrow function after the bone marrow transplantation as indicated. Granulocytes and platelets in blood began to increase from 10 to 14 days after the transplantation and became normal within three weeks after this. Serial measurements of S-GOT and alkaline phosphatase revealed reversible elevation, if any, within four weeks of the treatment. The number of our cases is still small, but results showed that autologous bone marrow transplantation made high dose chemotherapy possible. The necessity for consideration of the blood-brain barrier for this treatment is also discussed.

Implantable devices for chronic access and drug delivery to the central nervous system

This is a review of implantable devices for chronic access and drug delivery to the central nervous system (CNS) via the cerebrospinal fluid, extracellular fluid, and vascular pathways. The current applications of such devices in the management of mycotic meningitis, meningeal leukemia and carcinomatosis, solid malignant tumors of the CNS, intractable cancer-associated pain, unresectable cystic tumors and in cytologic, pharmacologic, and experimental studies on the cerebrospinal fluid (CSF) are assessed. Specific attention is paid to the applications of the most commonly used device, a subcutaneous reservoir and pump (SRP), including its major uses and complications. A new system for local chemotherapy of malignant gliomas, the tumor cyst device (TCD), is also described.

Diaziquone (AZQ)

Diaziquone is an aziridinylbenzoquinone with properties suggestive of an alkylating agent. The drug has shown broad antitumor activity against numerous transplantable murine tumors including curative activity against several intracerebrally implanted tumors. Parent diaziquone appears to have a t1/2 beta of approximately 30 min. The drug is rapidly and widely distributed to tissues as evidenced by a t1/2 alpha of approximately 1-3 min and a volume of distribution exceeding that of total body water. In addition, it rapidly penetrates the central nervous system, reaching peak concentrations (30-50%) of corresponding plasma levels) in approximately one hour. Diaziquone is rapidly and extensively metabolized by the liver. Diaziquone is a potent marrow suppressive agent inducing significant degrees of leukopenia, granulocytopenia, and thrombocytopenia in humans. Thrombocytopenia is often severe. Although myelosuppression is for the most part dose related, many patients had significant toxicity even at lower doses. Most investigators have attributed this to the extent of prior therapy. Diaziquone demonstrates a very steep dose-response relationship. Myelosuppression was the dose-limiting toxicity in all phase I trials. No nonhematologic dose-limiting toxicity has been identified to date. In phase I and preliminary phase II trials, diaziquone has demonstrated activity against primary brain tumors. Little activity has been seen in other tumor categories. It should be noted, however, that all studies to date have been carried out in heavily pretreated patients. Because of the broad spectrum of antitumor activity in experimental murine tumors, the lack of nonhematologic dose-limiting toxicity, the ability of this drug to attain significant levels in the central nervous system, and the activity of the drug in primary brain tumors, further studies examining its role in the management of patients with cancer are warranted. These studies should be conducted in patients who have had little or no prior therapy in order to better evaluate the efficacy of the drug.

Hemorrhagic encephalitis produced by selective non-occlusive intracarotid BCNU injection in dogs

A selective non-occlusive technique was developed for administration of BCNU (1,3-bis(2-chloroethyl)-1-nitrosourea) into the internal carotid artery of the dog, and the neuropathological effects in the brain were studied. One out of three dogs showed ipsilateral hemorrhagic necrotizing encephalitis at doses of 102 mg/sq m, and all of three dogs showed similar but more severe pathology at doses of 215 to 232 mg/sq m. This study and previous studies in the dog and monkey suggest definite thresholds above which cerebral toxicity occurs when BCNU is administered via the intracarotid route. Greater dilution of drug in the larger territory of supply of the human internal carotid artery allows somewhat higher doses in man. The pathology of the lesion induced by BCNU suggests a primary vascular injury as a pathogenic mechanism, consonant with similar findings following high-dose systemic BCNU administration in man. Investigators conducting ongoing and future trials of intracarotid BCNU in the human for the treatment of intracranial neoplasms should be especially vigilant for a similar toxic effect.

Sensitivity to 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) of glioma cells in vivo and in vitro

A new water-soluble nitrosourea (ACNU) was tested for its antitumor activity against four glioma cell lines. Four factors were studied to determine its antitumor activity: inhibition of cell growth, morphologic observation, analysis of DNA histogram with flow microfluorometry, and sensitivity testing with microtest plate. Growth inhibition in response to ACNU was seen in two cell lines (EA285, U251-MG), whereas two cell lines (YE2-02, T98) were resistant to ACNU. The results of the present sensitivity test concur with those of other examinations that this test is useful in selecting a drug and determining the effective dose.

Pharmacokinetic study of cerebrospinal fluid penetration of cis-diamminedichloroplatinum (II)

The ability of cis-DDP and several analogs to enter the CSF was investigated in rhesus monkeys that had subcutaneously implanted Ommaya reservoirs connected to catheters in each monkey's fourth ventricle. Plasma and CSF samples were analyzed for platinum content by atomic absorption spectroscopy. Plasma platinum curves were biphasic with a very slowly declining terminal phase. CSF platinum curves rose to maximum concentrations 30-40 min after an IV bolus injection and declined mono-exponentially (T 1/2 = 60 min) without displaying a detectable slow terminal phase. cis-DDP given as an IV bolus of 1.5 mg/kg or 3.0 mg/kg produced peak CSF concentrations of 0.35 and 0.78 microM platinum. The ratio of CSF platinum:plasma platinum never exceeded 0.04. When cis-DDP at 3.0 mg/kg was given as a 2- or 7-h infusion, the peak CSF concentrations were 0.28 and 0.17 microM platinum, respectively. The total CSF exposure, measured as concentration X time, was the same for bolus and for 2- and 7-h infusions. Studies with analogs showed that neither malonato 1,2-diaminocyclohexane platinum (II) nor 4-carboxyphthalato 1,2-diaminocyclohexane platinum (II) had better CSF penetrance than cis-DDP. Sulfato 1,2-diaminocyclohexane platinum (II) could not be detected in the CSF. The ratio of CSF platinum:plasma platinum was never greater tha 0.02-0.03 for any of the analogs.

Diffusion of a new beta-lactam (LY 127935) into cerebrospinal fluid. Implications for therapy of gram-negative bacillary meningitis

LY 127935, a new oxa beta-lactam with an expanded gram-negative spectrum, was administered intravenously to seven patients, including two patients with documented gram-negative bacillary meningitis. In the patients receiving continuous therapy (2 g intravenously every 8 hours) cerebrospinal fluid trough levels of LY were never less than 6 micrograms/ml. Peak cerebrospinal fluid levels of LY ranged from 25 to 39 micrograms/ml and occurred approximately 2.5 hours after the intravenous administration of the drug. Cerebrospinal fluid levels of LY were 19 per cent to greater than 100 per cent of simultaneous serum levels. Cerebrospinal fluid bactericidal activity was 1:4 to 1:256. Intravenous LY, because of its expanded gram-negative spectrum and excellent cerebrospinal fluid penetration, is a potentially useful antibiotic in the treatment of gram-negative bacillary meningitis.

Increased penetration of barbital through the bloodbrain barrier in the rat after pretreatment with probenecid

Some weak organic acids are eliminated from the brain by an acid transport system. The question arose is this system also used to transport drugs out of the brain? In that case probenecid pretreatment (100 mg/kg subcutaneously) should influence the induction time of a slightly lipid soluble barbiturate (barbital) which penetrates into the brain slowly, more than the induction time of a very lipid soluble barbiturate (hexobarbital). In the first experiment barbital (200 mg/kg) was given intraperitoneally and in the second experiment barbital (150 mg/kg) was infused intravenously during 10 min. In both experiments loss of righting reflex occurred more rapidly after pretreatment with probenecid compared with pretreatment with saline. Only in the second experiment did probenecid significantly increase the time during which the righting reflex was lost. In the next experiment hexobarbital was infused intravenously at a rate of 0.25 mg/kg/sec. until a burst suppression which lasted 1 sec. or more was seen in a concomitant EEG-record. When this "silent second" occurred the infusion was stopped and the ensuing anaesthesia times recorded. Probenecid had no effect on the induction when studied with this method, but the ensuing anaesthesia times were increased. The hypothesis of an acid transport system out of the brain was thus not refuted by these experimental results. Studies of brain concentrations of barbital also supported this finding. After 200 mg/kg intraperitoneally the concentration of barbital in the brain was higher after pretreatment with probenecid as compared to saline pretreated controls i.e. at times corresponding to the induction times in the in vivo experiments. No difference was found in the serum levels of barbital.

Acute lymphoblastic leukemia: treatment

Over the past thirty years, major progress has been achieved in the treatment of ALL. Many of the concepts, definitions, and principles of chemotherapy have and continue to be derived from studies in ALL. Major and continuing progress is ongoing for the various categories of treatment; that is, remission induction, treatment at sites of high risk for relapse (e. g., pharmacologic sanctuaries), cytoreductive therapy during complete remission, and duration of treatment. Rapid improvement in our understanding of the pathogenesis of ALL and particularly the identification of immunologic and prognostic subcategories of ALL have major therapeutic implications which are in process of being realized. Current research is focused on the development of new chemotherapeutic agents, the more rational basis for the employment of chemotherapeutic agents in combination (cytokinetic, pharmacologic, and related studies), a better definition of the host-tumor relationship particularly with respect to immunologic response and iatrogenic manipulation of such responses, and in the area of supportive care and bone marrow transplantation.

Direct administration of methotrexate into the central nervous system of primates. Part 2: Distribution of 3H methotrexate after intrathecal lumbar injection

The kinetics of distribution of 3H methotrexate (3HMTX) in the central nervous system, plasma, and urine after intraventricular, lumbar percutaneous puncture, and spinal catheter injections were compared. Levels of 3HMTX in whole brain after lumbar percutaneous injection were 40 times less than after intraventricular injection. Injection of 3HMTX via a spinal catheter increased the level of 3HMTX in whole brain but this was still tenfold less than after direct intraventricular instillation. Also, it was found that a disproportionately high amount of 3HMTX was in the brain-stem-cerebellum region which would further reduce the concentration of methotrexate in the cerebral hemispheres. Both intraventricular and lumbar spinal catheter administration of 3HMTX produced 3HMTX levels greater than 10(-6)M (moles/kg wet weight) in spinal cord tissue as measured by 3H specific activity between 2 to 8 hours after injection. Administration by lumbar percutaneous puncture, however, rarely resulted in this suggested therapeutic level of 10(-6)M. Initial 3HMTX levels in plasma after lumbar percutaneous instillation was 24 times greater than after intraventricular or lumbar spinal catheter injections. This indicated significant and unavoidable extradural leakage after lumbar percutaneous puncture, which may account for the substantially lower levels of 3HMTX in the brain and spinal cord tissue. It is concluded that intraventricular instillation of methotrexate is the best route of administering the drug to achieve therapeutic levels of methotrexate in both whole brain and throughout the spinal cord.

Central nervous system tumors of childhood treated with CCNU, vincristine, and radiation

CCNU was used in the treatment of 18 patients with childhood tumors of the CNS. Severe bone-marrow toxicity was noted. The initial dose was 130 mg/m2 given every 6 weeks, but it was often necessary to reduce the dose and prolong the interval between doses. The toxicity appeared to be much the same whether previous radiotherapy had been given to the whole CNS or to the brain only. In assessable patients with pur medulloblastoma, three out of three showed marked responses to CCNU. In those with a mixture of medulloblastoma and other tumor components, two out of two showed responses to CCNU. In children with astrocytomata of various types, only two out of six showed responses to CCNU, and in these the degree of response was slight. The results suggest that CCNU is a useful treatment for medulloblastoma but its value in the treatment of childhood astrocytoma is uncertain. In 6 patients who received both radiotherapy and CCNU, the contribution of the CCNU was not assessable.

Chemotherapy in recurrent noncystic low-grade astrocytomas of the cerebrum in children

Six children with grade II astrocytomas were treated with combination chemotherapy consisting of 1,3 bis(2-chloroethyl) 1-nitrosourea (BCNU). Vincristine (VCR), intrathecal Methotrexate (i.t. MTX), and Dexamethasone. Of the children, 3 showed a partial remission, and 1 other showed clinical improvement. Our data suggest that chemotherapy is effective in low-grade astrocytomas, and there is now a need for larger trials in low-grade astrocytomas to document the role of chemotherapy accurately in these tumors. It is suggested that trials of chemotherapy as adjuvant to surgery and radiotherapy should be initiated.

Multifocal leukoencephalopathy in adult leukemia: histologic features and etiologic considerations

A number of structural alteration in brains of leukemic children have been attributed to intrathecal administration of methotrexate and radiation therapy. We report an instance of asymptomatic encephalopathy in an adult who received thio-TEPA (by subarachnoid injection) as treatment for leukemic meningitis. The lesions were microscopic, confined to cerebral white matter and included: vacuolation, myelin destruction, axonal swelling, gliosis, deposition of mineral salts and aggregates of large foamy cells. The etiology of this condition remains undetermined.

Cerebrospinal-fluid concentrations of nitrazepam in man

The concentrations of nitrazepam in the plasma and cerebrospinal-fluid (CSF) of 38 neurological patients were determined by gas chromatography 2-36 hours after a single 5 mg oral dose. The percentage ratio between the mean CSF and the plasma concentrations increased from 8.0% at 2 hours to 15.6% at 36 hours. This percentage rise was significant (P less than 0.001). The maximum concentration of nitrazepam in the plasma was 36.7 +/- 5.7 ng/ml (at 2 hours) and CSF 3.0 +/- 0.3 ng/ml (at 4 hours). During the beta-phase the half-life of nitrazepam in plasma was about 27 hours and in the CSF markedly longer about 68 hours, indicating a very slow elimination of nitrazepam from the CSF.