Effect of dithiothreitol on lipid peroxidation induced modification of NMDA receptor in fetal guinea pig brain

The present study examines if the NMDA receptor modification induced by lipid peroxidation is mediated through its redox site and is therefore reversible by dithiothreitol (DTT) by performing [3H]MK-801 binding in the fetal guinea pig brain. P2 membrane fractions were prepared from fetal guinea pig brains and were peroxidized in vitro by 100 microM ascorbate and 25 microM ferric chloride for 20 min. Control and peroxidized membranes were then incubated with 100 microM DTT for 30 min at 37 degrees C. [3H]MK-801 binding was performed in DTT treated and untreated membranes in the presence of 100 microM each of glutamate and glycine. In addition, to study the glutamate- and glycine-dependent activation, [3H]MK-801 binding was determined in the absence (basal) and presence (activated) of glutamate and glycine. Bmax (number of binding sites) and Kd (affinity) of the binding sites were used as indices of NMDA receptor modification and its reversibility by DTT. After lipid peroxidation, the Kd value increased from 4.44 +/- 0.12 in control to 10.39 +/- 1.78 nM (P < 0.01) suggesting decreased affinity following lipid peroxidation. Following treatment with DTT, there was no significant change in Kd, but Bmax was significantly (P < 0.007) decreased in the peroxidized membrane. This suggests that DTT did not improve the affinity of the NMDA receptor of the lipid peroxidized membrane but may have a deleterious effect by reducing the number of binding sites. However, in the control membrane DTT significantly increased the affinity (P < 0.004) and the Bmax (P < 0.01) of the NMDA receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Cisplatin and radiation in the treatment of tumors of the central nervous system: pharmacological considerations and results of early studies

PURPOSE

To review the human central nervous system pharmacology of cisplatin, factors that affect cisplatin uptake in tumors, and use alone and with radiation for the treatment of primary brain tumors.

METHODS AND MATERIALS

The authors review their own prior published and unpublished experience and data published by other groups on the above issues.

RESULTS

Cisplatin is one of the most active chemotherapy drugs available for the treatment of solid tumors. It is synergistic with several other agents, including radiation. While it attains only low concentrations in the normal central nervous system, concentrations and plasma-tissue transfer constants for human intracerebral tumors are comparable to those in extracerebral tumors. Tumor type appears to be a more important determinant of platinum concentration than is tumor location, and gliomas do achieve lower concentrations than do other intracerebral or extracerebral tumors. Several other factors have also been identified that correlate with concentrations of cisplatin achieved in human tumors. While cisplatin alone and in combination with other drugs does have some degree of efficacy against primary brain tumors, combining it with cranial irradiation has generally not resulted in any substantial improvement in outcome to date, although some individual studies have been somewhat encouraging. New approaches are currently under investigation.

CONCLUSION

Human pharmacology studies provide a rationale for use of cisplatin in the treatment of human brain tumors, and human and in vitro studies suggest some manipulations that might potentially further augment tumor platinum concentrations. While clinical studies suggest that cisplatin combinations may be of some value vs. human primary brain tumors and brain metastases, and while in vitro studies suggest that cisplatin potentiates radiation efficacy, no combination of cisplatin plus radiation yet tested has appeared to be superior to radiation alone.

Misalignment of pulmonary veins with alveolar capillary dysplasia: affected siblings and variable phenotypic expression

Misalignment of pulmonary veins with alveolar capillary dysplasia is recognized as a rare cause of persistent pulmonary hypertension of the neonate. Until now, misalignment of pulmonary veins was thought to be a random occurrence, but its appearance in siblings at our institution suggests that there may be a familial predisposition. There have been reports of variable expression and variable severity in this disease; our report describes this variability in family members.

Factors affecting human autopsy kidney-cortex and kidney-medulla platinum concentrations after cisplatin administration

The objective of this study was to determine factors that affect cisplatin concentrations in human kidney cortex. We used flameless atomic absorption spectrophotometry to assay platinum in autopsy specimens of kidney cortex obtained from 83 cisplatin-treated patients. Concentrations were correlated with pretreatment factors and treatment conditions using univariate nonparametric statistics. Hierarchical stepwise multiple regression analyses of transformed (to normalize) data were then used to assess which factors were most important, controlling for other factors. Kidney-cortex platinum concentrations varied from 0 to 14.8 micrograms/g (median, 2.04 micrograms/g). The cumulative lifetime dose of cisplatin ranged from 10 to 1120 mg/m2 (median, 112 mg/m2). The time from the last cisplatin dose to death was < 1-609 days (median, 38 days). According to univariate statistics, factors that correlated (P < 0.05) with kidney-cortex platinum concentrations were the cisplatin dose per course, the pretreatment serum urea level, metoclopramide use (positive correlations), the time from the last cisplatin treatment to death, and the pretreatment serum albumin value (negative correlations). Factors that approached significance (0.05 < or = P < or = 0.10) were a history of hypertension, hyperbilirubinemia (positive), the serum calcium level, and phenytoin use (negative). In the multiple regression analysis, after controlling for the cisplatin dose per course and the time from the last treatment to death, only concurrent metoclopramide and phenytoin use entered the model. The hydration volume did not affect corrected kidney-cortex or kidney-medulla platinum concentrations. The following conclusions were reached: (1) it may be feasible to use lower hydration volumes than those used routinely, (2) any effect of hydration volume on cisplatin nephrotoxicity may not be mediated via a reduction in kidney-cortex platinum concentrations, (3) higher cisplatin doses might be tolerated with new 5-hydroxytryptamine-3 (5HT-3) antiemetics than were tolerated with metoclopramide, and (4) phenytoin should be tested for its ability to reduce cisplatin nephrotoxicity.

Structure/function studies of HIV-1(1) reverse transcriptase: dimerization-defective mutant L289K

Virion-derived HIV-1 reverse transcriptase (RT) has subunits of molecular mass 66 and 51 kDa (p66 and p51, respectively) in an approximately 1:1 ratio. Since enzyme activity appears to depend on dimerization of these subunits, identification of critical regions of primary sequence required for proper dimerization could lead to potential targets for antiviral therapy. A central region of primary sequence contains a leucine hepta-repeat motif from leucine 282 to leucine 310 that has been suggested to be involved in dimerization [Baillon, J. G., Nashed, N. T., Kumar, A., Wilson, S. H., & Jerina, D. M. (1991) New Biol. 3, 1015-1019]. A region including this hepta-repeat was recently shown to be involved in protein-protein interactions required for dimerization [Becerra, S. P., Kumar, A., Lewis, M. S., Widen, S. G., Abbotts, J., Karawya, E. M., Hughes, S. H., Shiloach, J., & Wilson, S. H. (1991) Biochemistry 30, 11708-11719]. To investigate the role of this repeat motif in dimerization, we performed site-directed mutagenesis of these leucine residues from position 282 to position 310. Mutations were introduced into p66 and p51 RT coding sequences, and the individually purified RT subunit polypeptides were compared with wild-type polypeptides for dimerization. Physical characterization of the purified mutant peptides was conducted by circular dichroism analysis. Binding between p66 and p51 was studied by gel filtration, ultracentrifugation, and CD analysis. L289K-p66 was unable to dimerize with itself and wild-type or L289K-p51. The leucine repeat motif in the p66 subunit appears to be critical in formation of the heterodimer.(ABSTRACT TRUNCATED AT 250 WORDS)

Concentrations of doxorubicin and its metabolites in human autopsy heart and other tissues

PURPOSE

Since doxorubicin causes cardiotoxicity, we wished to assess relative concentrations of doxorubicin and its metabolites in cardiac tissues of patients who had been treated antemortem. We also wished to determine factors that correlate with human cardiac doxorubicin and doxorubicinol concentrations.

PATIENTS AND METHODS

Autopsy tissues were collected from 35 patients who had received doxorubicin at any time antemortem, and were assayed by high pressure liquid chromatography.

RESULTS

The major species found in human autopsy cardiac tissues were doxorubicinol (median concentration 92 ng/g, range 0 to 484 ng/g), and doxorubicin (median 58 ng/g, range 0-1665 ng/g). Other doxorubicin metabolites were detected in cardiac tissues in < half the patients. Of ten organs studied, heart ranked fifth with respect to median doxorubicin concentration and ranked fourth with respect to median doxorubicinol concentration. By multiple stepwise regression analysis, factors most closely associated with cardiac doxorubicin concentrations were time from last treatment divided by dose intensity, serum total protein, albumin, and hemoglobin (negative correlations). Factors most closely associated with cardiac doxorubicinol concentrations were cumulative doxorubicin dose, total protein, hemoglobin, and uric acid (positive associations), and respiratory rate (negative association). The physiologic significance of these associations (if any) is uncertain. By paired t-tests, cardiac doxorubicin and doxorubicinol concentrations were significantly (p < 0.05) higher than concentrations in skeletal muscle and smooth muscle organs.

CONCLUSIONS

Overall, the results suggest that the much greater tendency to develop doxorubicin toxicity in heart than in other types of muscle may be due to a propensity of cardiac muscle to accumulate doxorubicin. The results also suggest that doxorubicinol may play a role in doxorubicin cardiac toxicity, and that doxorubicin may be gradually converted to doxorubicinol in human tissues.

A phase I and pharmacokinetic study of intraperitoneal carboplatin and etoposide

BACKGROUND

We attempted to determine the maximum tolerated dose and toxicity of etoposide (VP-16) when administered in combination with carboplatin (CBDCA) (300 mg m-2) and administered via the intraperitoneal (IP) route.

METHODS AND MATERIALS

A total of 26 patients were treated on this trial. CBDCA was administered at a fixed dose of 300 mg m-2) while VP-16 was started at a dose of 200 mg m-2 and escalated at 50 mg m-2 increments. Both agents were mixed together in 2 litres of 5% Dextrose and administered as quickly as possible into the peritoneal cavity. Pharmacokinetic studies were performed at the maximum tolerated dose (MTD).

RESULTS

The MTD for this regimen was CBDCA 300 mg m-2 and VP-16 350 mg m-2. Patients > or = 70 years of age or who had received more than six cycles of previous chemotherapy, tolerated this regimen poorly. The MTD for this group of patients was CBDCA 200 mg m-2 and VP-16 50 mg m-2. Neutropenia was the dose limiting toxicity for both groups. The mean peritoneal/plasma peak ratio was 18.3 for CBDCA and 12.7 for VP-16. The pharmacologic advantage (peritoneal/plasma AUC ratio) was 14.9 for CBDCA and 8.8 for VP-16. Although measurable disease was not a requirement for entrance into this study a response rate of 27% was noted in 15 patients with evaluable disease who had ovarian cancer.

CONCLUSIONS

A pharmacologic advantage exists for both CBDCA and VP-16 when administered together via the IP route.

High-dose biweekly intraperitoneal cisplatin: an effective way to increase cisplatin dose intensity

The amount of cisplatin (DDP) delivered per unit time (dose intensity, expressed in mg/m2/week) may be an important factor in determining the clinical outcome in tumors such as ovarian carcinoma. In this neoplasm, intraperitoneal chemotherapy is an effective form of treatment. In this trial we have explored the tactic of shortening the cycle interval as a way to increase the dose intensity of ip DDP. Sixteen patients with a variety of solid tumors received a total of 77 cycles of DDP 180 mg/m2 instilled ip concurrent with i.v. sodium thiosulfate at the dose of 4 g/m2 as loading dose, followed by 12 g/m2 over 6 hr. Each cycle was repeated every 2 weeks. The number of cycles delayed for 3 or more days was 28 (36%). The mean DDP dose intensity received by these patients was 77% of the planned dose or 69 mg/m2/week (confidence interval 95%, 60.5-77.5). The treatment was generally well tolerated: myelotoxicity was mild, only 1 patient had an increase in serum creatinine to > 2 mg/dl. Five patients (31%) developed symptoms of peripheral neuropathy. All patients were evaluable for response. The overall response rate (complete plus partial) in these heavily pretreated patients was 19%. When DDP is given in high doses by the ip route concurrently with systemic sodium thiosulfate, the dosing interval can be reduced to every 2 weeks permitting a marked increase in DDP dose intensity.

Catalytic antibody activity elicited by active immunisation. Evidence for natural variation involving preferential stabilization of the transition state

1. The hydrolytic activity of IgG purified from (a) 13 samples of ovine antiserum collected from three animals during a two-year immunisation programme using a phosphate immunogen (comprising the amide conjugate bonded through the carboxy group of 4-nitrophenyl 4-carboxymethylphenyl hydrogen phosphate and amino groups of keyhole-limpet haemocyanin) and (b) a sample of ovine antiserum collected from another animal during an 18-week immunisation programme using an analogous sulphone immunogen (comprising the amide conjugate bonded through the amino group of 4-nitrobenzyl, 4-(4-aminobutoxy)benzyl sulphone and carboxyl groups of keyhole-limpet haemocyanin) were evaluated kinetically by using 4-nitrophenyl 4-(3-aza-2-oxoheptyl)phenyl carbonate and 4-nitrophenyl 4-(2-hydroxyethoxy)phenyl carbonate as substrates. 2. Catalytic activity was found in all 13 samples of anti-phosphate IgG but was absent in the sample of anti-sulphone IgG as well as in all samples of IgG isolated from the serum of non-immunised animals. These findings, taken together with the lack of catalytic activity of the anti-phosphate IgG towards the 2-nitrophenyl 4-(3-aza-2-oxoheptyl)phenyl carbonate, compel the view that the catalytic activity of the anti-phosphate IgG preparation is entirely antibody-mediated and is not due to contaminant hydrolytic enzymes. The fact that catalytic activity was found in all 13 samples of the anti-phosphate IgG provides the first evidence that it is possible, as a routine, to elicit a catalytic antibody response in a host animal via active immunisation. 3. The nature of the, albeit small, variation in the catalytic characteristics of the anti-phosphate IgG (increase in both kcat, the catalytic rate constant calculated as V/2[IgG] and kcat/Km, the apparent second-order rate constant for the overall catalysed conversion of substrate to products, with increase in Km suggests simultaneous improvement in transition state binding and deterioration in substrate binding as predicted from immunogen design and the postulated general mechanistic basis of antibody catalysis. 4. This interpretation is supported by the difference in the values of the dissociation constant Ki for the competitive inhibition by the transition-state analogue 4-methylphenyl 4-nitrophenyl hydrogen phosphate of reactions catalysed by two representative anti-phosphate IgG samples: for the catalysis with Km = 4.5 microM, Ki = 9 nM and for that with Km = 1.3 microM, Ki = 80 nM.(ABSTRACT TRUNCATED AT 400 WORDS)

Modification of NMDA receptor by in vitro lipid peroxidation in fetal guinea pig brain

The effect of lipid peroxidation on the NMDA receptor and its modulatory sites in fetal guinea pig brain cell membranes was examined. P2 membrane fractions were prepared from the fetal brain tissue and peroxidized in the presence of ferric chloride and ascorbate. [3H]-MK-801-binding studies were performed and Bmax (number of binding sites) and Kd (affinity) values were used as indices of NMDA receptor modification. In lipid-peroxidized membranes the Kd value increased from 6.76 +/- 2.69 in control to 15.12 +/- 7.38 nM (P < 0.01), indicating a decreased affinity of NMDA receptors following lipid peroxidation. However, there was no significant change in Bmax. The glutamate- and glycine-dependent increase in activation was 40% lower in lipid-peroxidized membranes as compared to control. The spermine-dependent activation was also significantly reduced following lipid peroxidation as compared to control suggesting decreased affinity of spermine site. The results of this study indicate that lipid peroxidation modifies recognition, coactivator and spermine sites of NMDA receptor by decreasing its affinity without affecting the number of binding sites. Normal activation of NMDA receptor is important for neuritic growth, synaptogenesis, long-term potentiation and synaptic plasticity. Therefore, we speculate that any clinical condition causing lipid peroxidation of brain cell membranes could jeopardize these maturational processes in the developing brain causing neurological impairment.

Dose intensification of cisplatin chemotherapy through biweekly administration

PURPOSE

Dose intensity (DI, expressed in mg/m2/wk) may be an important factor in the clinical use of cisplatin (DDP). We have explored the shortening of the cycle interval as a way to increase the DI of DDP.

PATIENTS AND METHODS

DDP 180 mg/m2 was given intravenously (i.v.) over 4 hours; sodium thiosulfate (STS) was given i.v. in the opposite arm at a loading dose of 4 g/m2, followed by 12 g/m2 over 6 hours. Each cycle was repeated every two weeks. Seventy-five cycles were administered to 28 patients in this clinical trial.

RESULTS

In 19 patients who received 2 or more cycles of chemotherapy, a delay of three or more days was required on 17/66 courses (26%); the mean DDP DI actually received by these patients was 83 mg/m2/wk (88% of the planned DI). The major side effect was ototoxicity; this occurred in 9 patients (33%), but none required a hearing aid. Myelosuppression was moderate with thrombocytopenia greater than neutropenia. Nephrotoxicity (creatinine > 2 mg/dl) occurred on only 2 cycles (3%). Three patients (11%) developed symptoms of peripheral neuropathy. In 23 evaluable patients, the overall response rate was 39%.

CONCLUSION

It is feasible to give 180 mg/m2 of DDP and STS every two weeks with tolerable nephrotoxicity but without blocking other types of toxicity, such as myelosuppression and ototoxicity. The shortening of cycle intervals resulted in a markedly increased DI.

Selective sensitivity of synaptosomal membrane function to cerebral cortical hypoxia in newborn piglets

The effect of hypoxia on the structure and function of the synaptosomal membranes and myelin fraction (glial cells, neuronal cells bodies and axonal membranes) was investigated by measuring Na+,K(+)-ATPase activity and levels of lipid peroxidation products in cerebral cortical synaptosomal membranes and myelin fractions obtained from newborn piglets. Hypoxic hypoxia was induced and cerebral hypoxia was documented as a decrease in the ratio of phosphocreatine to inorganic phosphate (PCr/Pi) using 31P-NMR spectroscopy. PCr/Pi decreased from baseline of 2.93 +/- 0.76 to 0.61 +/- 0.36 during hypoxia. The synaptosomal membrane Na+,K(+)-ATPase activity decreased from a control value of 56.6 +/- 3.7 to 40.4 +/- 6.0 mumol Pi/mg protein/h during hypoxia. The level of conjugated dienes increased from zero (reference value) to 4.5 +/- 2.7 nmol/mg lipid and the level of fluorescent compounds increased from 23.5 +/- 2.2 to 92.6 +/- 46.4 ng quinine sulfate/mg lipid in the synaptosomal membranes during hypoxia. No change in myelin fraction Na+,K(+)-ATPase activity or levels of lipid peroxidation products were noted. These data indicate that synaptosomal membranes, rich in polyunsaturated fatty acids, are more susceptible to oxygen free radical mediated lipid peroxidative damage during hypoxia.

Human autopsy-tissue distribution of menogaril and its metabolites

Autopsy-tissues were obtained from eight patients who had last received menogaril (total cumulative dose, 175-1080 mg/m2) intravenously (one patient) or orally (seven patients) from 1 to 285 days prior to death. Tissue samples were assayed for menogaril and its metabolities by high-pressure liquid chromatography. Unchanged menogaril was found only in a single lung-tissue sample from a patient who had died < 24 h after receiving his last treatment. N-Demethylmenogaril was found in two lung-tissue samples and in single samples of the thyroid, lymph node, pancreas, cerebellum, and tumor. The major menogaril metabolite found in human autopsy-tissues was 7-deoxynogarol. The highest 7-deoxynogarol concentrations were found in the large bowel (median, 201 ng/g), liver (median, 183 ng/g), and lung (median, 177 ng/g). The heart ranked as the 9th of 18 organs in median 7-deoxynogarol concentration, after the large bowel, liver, lung, tumor, thyroid, skeletal muscle, adrenal gland, and kidney. The lowest concentrations were detected in brain tissue. Our results suggest that the low degree of cardiac toxicity and the possible pulmonary toxicity of menogaril may be related to relative tissue concentrations of menogaril metabolites. Tumor 7-deoxynogarol concentrations were comparable with those in normal tissues, except that concentrations in intracerebral tumors were higher than those in the normal brain. Tissue 7-deoxynogarol concentrations appeared to be directly related to the cumulative dose and inversely related to the time from the last treatment to death; the value obtained by dividing dose by time correlated (P < 0.05) with tissue 7-deoxynogarol concentrations.

Human autopsy tissue distribution of the epipodophyllotoxins etoposide and teniposide

Autopsy tissues were collected from ten patients who had received etoposide, 150-3480 mg, from 1 to 412 days antemortem and from five patients who had received teniposide, 234-1577 mg, from 3 to 52 days antemortem. Tissues were assayed for etoposide and teniposide using high-pressure liquid chromatography with electrochemical detection. Etoposide was detectable in tissues of three of four patients dying < 5 days after their last etoposide treatments to cumulative doses of 150-432 (median, 280) mg but was detectable in tissues of only one of six patients dying 7-412 (median, 37) days after their last etoposide treatment to a cumulative dose of 607-3600 (median, 1553) mg. The highest tissue concentrations were in the small bowel, prostate, thyroid, bladder, spleen, and testicle. Intermediate concentrations were found in the lymph node, skeletal muscle, adrenal gland, stomach, tumor, liver, lung, pancreas, and kidney, and the lowest concentrations were found in the heart, brain, diaphragm, vagina, and esophagus. Teniposide was detectable in one patient dying 3 days after a cumulative teniposide dose of 576 mg (spleen, prostate, heart > large bowel, liver, pancreas > thyroid, adrenal, stomach, small bowel, bladder, testicle, and skeletal muscle) but was not detectable in any tissue from four patients dying 5-52 (median, 8) days after their last treatment to a cumulative teniposide dose of 234-1577 (median, 520) mg. The very short tissue half-life contrasts with our previous observations for human autopsy tissue concentrations of mitoxantrone, doxorubicin, menogaril metabolites, diaziquone, and amsacrine. The short tissue half-life may help explain the schedule dependency of epipodophyllotoxin efficacy and may also help explain the lack of visceral toxicity of these compounds.

Pharmacokinetic study of intraperitoneal streptozotocin

Streptozotocin, a nitrosourea, has limited antitumour activity. However, in concentrations and exposures higher than those achieved after intravenous dosing, streptozotocin has been reported to sensitize various cell lines in vitro to other nitrosoureas or alkylating agents. We hypothesized that the intraperitoneal administration of streptozotocin would achieve concentrations and exposures in the peritoneal cavity sufficient for this sensitization to take place. The pharmacokinetics of streptozotocin in the peritoneal cavity and in plasma were determined in patients who received 1 g of streptozotocin via the intraperitoneal route. Fifteen courses were administered to 12 patients. The mean total area under the concentration versus time curves (AUC) was 183 +/- 31 (SE) mM min in the peritoneal cavity (5 courses) and 5.3 +/- 1.1 (SE) mM min in plasma (6 courses). The mean peritoneal to plasma AUC ratio was 64 +/- 23 (5 courses). The mean peak streptozotocin concentrations in the peritoneal cavity (5 courses) and plasma (6 courses) were 1.9 +/- 0.4 mM and 0.03 +/- 0.01 mM, respectively. No significant toxicity was observed on any course. We conclude that intraperitoneal administration of streptozotocin is feasible, and that drug concentrations and exposures are in an appropriate range in the peritoneal cavity to cause sensitization to other nitrosoureas.

A nuclear magnetic resonance investigation of the upper airways in ferrets. II. Contrast-enhanced imaging to distinguish vascular from other nasal fluids

Proton magnetic resonance imaging (MRI), used in conjunction with the intravascular contrast agent albumin-(Gd-DTPA), provides a means to distinguish vascular fluids from other nasal fluids in the upper airways. Ferrets were given an intravenous dose of albumin-(Gd-DTPA) followed by an intranasal challenge with either histamine (HS) or methacholine (MC). An observed increase in image intensity indicates that HS and MC both cause an accumulation of fluids in the nasal turbinate region. The MRI data are also influenced by the presence of blood, which contains the contrast agent, and a clear distinction can be made between vascular fluids and other nasal fluids (i.e., cellular and glandular secretions). The results show that HS causes an increase in vascular fluids in the nasal turbinates while MC does not. This methodology represents a new means to investigate airway pharmacology and the pathophysiology associated with various pharmacological agents, allergens, or viral infections.

A polyclonal antibody preparation with Michaelian catalytic properties

1. 4-Nitrophenyl 4'-(3-aza-2-oxoheptyl)phenyl carbonate (I), an amide conjugate (XI) involving the carboxy group of 4-nitrophenyl 4'-carboxymethylphenyl phosphate and an amino group of keyhole-limpet haemocyanin, and a fluorescein derivative (XVII) were synthesized. 2. The conjugate (XI) was used as an immunogen with which to raise polyclonal antibodies in multigeneration cross-bred sheep; the fluorescent derivative (XVII) was used for the initial assessment of the antisera via binding assays monitored by fluorescence polarization; the carbonate ester (I) was used as a chromogenic substrate for the investigation of catalytic activity. 3. The IgG from the antiserum of sheep no. 270 was isolated by Na2SO4 precipitation and chromatography on Protein G-Sepharose. 4. This preparation of IgG catalysed the hydrolysis of the carbonate ester (I); the catalysis at pH 8.0 and 25 degrees C obeyed Michaelis-Menten kinetics with at least 25 turnovers, Km = 3.34 microM, and lower limits for kcat. of 0.029 s-1 and for kcat./Km of 8.77 x 10(3) M-1.S-1, on the unlikely assumption that the concentration of catalytic antibody is provided by twice the total IgG concentration (two sites per molecule); probable estimates of the fraction of the total IgG that is anti-haptenic IgG and of the fraction of this that is catalytically active suggest that the values of kcat./Km are actually very much larger than these lower limits. 5. The failure of the antibody preparation to catalyse the hydrolysis of the isomeric 2-nitrophenyl carbonate (II), which differs from compound (I) only in the position of the nitro substituent in the leaving group, compels the view that catalytic activity is due to antibody rather than contaminant enzyme; this conclusion is supported by (a) the failure of the following to discriminate effectively between the isomeric substrates (I) and (II): pig liver carboxylesterase, rabbit liver carboxylesterase (collectively EC 3.1.1.1), whole serum from a non-immunized sheep and whole serum from a sheep immunized with a derivative of 3-O-methylnoradrenaline and (b) the lack of catalytic activity in IgG preparations from sheep immunized with sulphoxide or sulphone analogues of immunogen (XI). 6. The various parameters used for the comparison of the kinetic characteristics of hydrolytic catalytic antibodies are discussed. 7. The characteristics of hydrolysis of compound (I) catalysed by the present polyclonal antibody preparation are shown to be substantially better in most respects than those of analogous reactions of two other carbonate esters catalysed by monoclonal antibodies.

Frontal bone osteomyelitis causing recurrent meningitis

A case of recurrent pyogenic meningitis is reported. The focus for recurrent meningeal infection was frontal bone osteomyelitis secondary to a road accident which the patient sustained ten years earlier.

A phase II trial of intraperitoneal cisplatin and etoposide as salvage treatment for minimal residual ovarian carcinoma

We conducted a phase II study of intraperitoneal (IP) cisplatin (CDDP) and etoposide (VP-16) as salvage therapy in patients with ovarian cancer who had persistent disease or who had relapsed after primary systemic chemotherapy and had residual disease of less than 2 cm. Two hundred eleven courses of IP chemotherapy consisting of CDDP 200 mg/m2 and VP-16 350 mg/m2 were administered. All patients received intravenous (IV) thiosulfate protection. Treatment was given once every 4 weeks for a median of six cycles. Twenty-four of 37 assessable patients were clinically free of disease at the end of treatment (normal physical exam, computed tomographic [CT] scan, CA-125 and peritoneal cytology); one patient had a partial response. Ten of these 24 patients consented to reexploration at the end of treatment, and nine were in pathologic complete remission, while one patient had positive peritoneal washings as her only evidence of persistent disease. The median survival of the 37 patients was 26 months from the first day of IP treatment and 51 months from diagnosis. The major toxicity was myelosuppression, with median nadir WBC, granulocyte, and platelet counts of 2,400, 684, and 134,000/mm3, respectively. There was no cumulative renal damage, hypomagnesemia, or chemical peritonitis. We conclude that IP CDDP and VP-16 can produce pathologic complete remissions when used as a second-line regimen for patients with ovarian cancer who have received systemic cisplatin-based therapy and have less than 2 cm disease.

Experimental immune complex-mediated glomerulonephritis in the nonhuman primate

This study was undertaken to develop a model of immune complex (IC)-mediated glomerulonephritis (GN) in the nonhuman primate that could be used in subsequent studies to examine critically the role of the erythrocyte complement receptor (E-CR) in the pathogenesis of IC-mediated disease. Cynomolgus monkeys were chosen for study because they constitutively express E-CR levels that are either less than, equal to, or greater than that seen in normal man. After immunization with bovine gamma globulin (BGG), the GN induction protocol was begun in 10 cynomolgus by initiating daily i.v. administration of BGG in amounts sufficient to achieve or exceed antigen/antibody equivalence (assessed by the quantitative precipitin assay) for precipitating antibody present in the plasma volume. We found that within eight weeks of daily BGG administration of all the cynomolgus developed IC-mediated GN, irrespective of the initial E-CR level of the animals. However, the high E-CR cynomolgus tended to receive the higher BGG doses because of higher initial antibody levels to BGG. When the total number of glomerular deposits (determined by morphometric studies) per total BGG dose for each animal was plotted against the initial CR/E of that animal, there was a tendency for the animals with higher CR/E levels to have a lower number of glomerular deposits/BGG dose (r = 0.62, P = 0.06). Also, the total number of glomerular deposits correlated with the severity of the GN. During the early weeks of the GN induction protocol, the IC that formed in vivo (assessed by infusion of 125I-BGG) bound in large amounts to the circulating erythrocytes of the cynomolgus with medium or high E-CR levels. However, when tested after the onset of heavy proteinuria, which occurred between weeks 5 and 8 of daily BGG administration, the IC that formed in the circulation bound only poorly to circulating erythrocytes. By this time the E-CR levels had declined to 43 +/- 9% of initial values (P less than 0.01). This study demonstrates that: 1) A workable model of IC-mediated GN has been developed in the nonhuman primate. 2) During the induction of GN, CR/E and the ability of the erythrocyte to bind IC in vivo are decreased significantly. This suggests that an intact E-CR system could play a role in the protection against IC-mediated disease. However, further study will be needed to test that hypothesis critically. The present model should be useful in such studies.

Production of cellulolytic enzymes by immobilized Sporotrichum thermophile

Spores of Sporotrichum thermophile were immobilized in agar, polyacrylamide, and sodium alginate to generate in situ mycelium for production of cellulolytic enzymes. Immobilized mycelium was considerably less effective than free cells for cellulase productivity. Of the three gel types, agar beads proved to be the best carrier for the immobilized spores and subsequently generated mycelium. Results of repeated batch experiments suggested that the immobilized mycelia could be reused but at much reduced efficiency.

Excess sucrose and glucose ingestion acutely elevate blood pressure in spontaneously hypertensive rats

Spontaneously hypertensive rats (SHR) were fed 6 different diets. The baseline diet (I) derived equal calories from sucrose, proteins, and fats. Three other diets (II, III, VI) derived the majority of calories from refined CHO, sucrose or glucose, with decreases in calories from proteins or fats. The last two diets (IV, V) were relatively low in sucrose with a higher percentage of the total calories from proteins and fats, respectively. From 3 to 15 weeks on the diets, the highest average BP was in rats consuming high concentrations of sucrose or glucose (II, III, VI). Urinary excretory rates of norepinephrine (NE) at 5, 10 and 15 weeks and epinephrine at 5 and 10 weeks were significantly elevated in rats ingesting diets high in refined CHO, and NE positively correlated with blood pressure (BP) at 5 and 10 weeks of the study. At the end of the study, serum insulin levels were not different, but plasma renin and serum glucagon levels were lower in SHR consuming the diets with high CHO concentrations. We conclude that equally elevated BP are seen with relatively high intakes of either sucrose or glucose, whether the balance of calories is derived from lessening fat or protein. This is secondary, at least in part, to alterations in NE metabolism.

The effect of corticosteroid administration on bleomycin lung toxicity

Bleomycin is well recognized as an active antineoplastic agent in the treatment of germ cell tumors. Pulmonary toxicity is the most significant complication of bleomycin administration. In this report, an attempt is made to modify both the incidence and severity of this side effect. One hundred eleven patients with advanced germ cell tumors were treated with a combination chemotherapy program that included the administration of 30 units (U) of bleomycin as a continuous infusion daily for 3 days every 3 weeks rather than a weekly bolus injection of a total of 360 U (mean dose received, 307 U). Also, 31 patients received high-dose steroids, which have been shown to modify bleomycin-induced pulmonary toxicity, for the treatment of chemotherapy-induced emesis. Changes in carbon monoxide diffusion capacity (DLCO) prompting cessation of bleomycin therapy occurred in 15 cases (bleomycin was stopped in one case due to dyspnea and lung infiltrates, and one patient suffered fatal respiratory failure probably due to bleomycin lung toxicity). Thus, probable bleomycin pulmonary toxicity changed the clinical treatment in 15.3% of the cases. On long-term follow-up, only two patients have demonstrated a residual decrease in DLCO. The incidence of a greater than 25% decrease in DLCO was 34% and was not significantly altered by the administration of steroids (P = 0.96). It is possible, however, that the low incidence of clinically significant and fatal pulmonary toxicity, as experienced in this group of patients, may be related to the infusion of bleomycin. It also is possible that the reversibility of the decrease in DLCO in 95% of the patients may be related to the duration and schedule of bleomycin administration. As bleomycin continues to be an important drug in the treatment of advanced germ cell tumors, further studies are warranted to evaluate the role of the continuous infusion of bleomycin as opposed to bolus therapy.

Comparison of the pharmacokinetics of ultrafilterable cisplatin species detectable by derivatization with diethyldithiocarbamate or atomic absorption spectroscopy

The pharmacokinetics of the cisplatin (DDP) species detected by measurement of diethyldithiocarbamate (DDTC)-reactive species (DDTC-DDP) were compared to the pharmacokinetics of the species detected by measurement of total ultrafilterable platinum in patients receiving DDP alone or in combination with the nephroprotective agent sodium thiosulfate. The doses of DDP studied were 100 mg/m2 (11 courses given to eight patients) and 202.5 mg/m2 (five courses given to four patients) given as 2 h i.v. infusions, the latter with concurrent thiosulfate. When DDP was given alone (100 mg/m2) the two assays yielded the same area under the curve (AUC) values for DDTC-DDP and total ultrafilterable platinum during the first 4 h after the start of infusion; however, beyond 4 h post-infusion, the AUC for total ultrafilterable platinum was consistently greater than that for DDTC-DDP. When DDP was given with thiosulfate (202.5 mg/m2), the AUC for total ultrafilterable platinum was significantly greater than that of DDTC-DDP during the whole sampling period. The ratio of the AUC for total ultrafilterable platinum to DDTC-DDP, when DDP was given with thiosulfate, was barely significantly greater than that when DDP was given alone. These data indicate that during and immediately following a short infusion of DDP the major platinum-containing species present in plasma ultrafiltrate are still capable of reacting with nucleophilic sites on molecules such as DDTC; however, as the reactive species are eliminated, longer half-lived non-reactive ultrafilterable platinum species begin to predominate. They also indicate that although thiosulfate does neutralize a measurable amount of DDP in the plasma on the schedule employed, this degree of neutralization is not sufficient to explain the protection against DDP-induced nephrotoxicity produced by thiosulfate.

A phase II trial of intraperitoneal cisplatin and etoposide for primary treatment of ovarian epithelial cancer

We conducted a phase II trial of intraperitoneal (IP) cisplatin (DDP) and etoposide (VP-16) in stage III and IV newly diagnosed ovarian carcinoma patients with residual disease of any size. Twenty-three patients were entered, 19 had stage III and four stage IV disease. DDP 200 mg/m2 and VP-16 350 mg/m2 were given in 2 L saline IP via a Port-A-Cath (Pharmacia-Deltec, St Paul, MN). Sodium thiosulfate 4 g/m2 was given intravenously (IV) just before the start of IP instillation, and continued as a constant IV infusion of 2 g/m2/hr IV for a total of 6 hours. Treatment was given once every 4 weeks; six cycles of therapy were planned. Thirteen patients (56%) were in complete clinical remission at the end of treatment (normal physical exam, computed tomographic [CT] scan, CA-125, and peritoneal cytology). Seven of these 13 underwent a second-look laparotomy: three (13%) were in pathologic complete remission and four (17%) had microscopic disease only. Projected survival is 68% at 27 months, with 10 patients being alive and continuously free of disease. There was a very rapid fall in mean CA-125 to within normal limits at the end of the second course of treatment. The major toxicity was myelosuppression with median nadir WBC, granulocyte, and platelet counts of 2,600, 896, and 205,000/microL, respectively. There was no cumulative renal damage, anemia, hypomagnesemia, or chemical peritonitis. Neurotoxicity was similar to that observed with IV dosing. We conclude that therapy with the IP DDP/VP-16/IV thiosulfate regimen, in which all cytotoxic drugs are given only by the IP route, produces less anemia and renal damage than standard IV DDP-containing regimens, and that survival with this regimen appears to be at least as good as that produced by IV programs.

Effect of sodium thiosulfate on the pharmacokinetics and toxicity of cisplatin

Concurrent administration of sodium thiosulfate (STS) can protect against the nephrotoxic effects of even very-high-dose cisplatin (CDDP) (i.e., 270 mg/m2 given intraperitoneally). The effect of STS on the pharmacology and toxicity of CDDP was investigated in patients receiving at each treatment 90 mg of CDDP/m2 intraperitoneally, with STS given concurrently on alternate cycles by the intravenous route. The patients received a total of 38 courses of therapy, 21 without STS and 17 with STS. STS reduced the total exposure to diethyldithiocarbamate-reactive CDDP for the peritoneal cavity and plasma by 36% and 25%, respectively. When given alone, CDDP caused a statistically significant acute reduction in creatinine clearance levels; this reduction was less evident when STS was given. We conclude that, whereas STS does reduce systemic exposure, the magnitude of this effect was not sufficient to account for the ability of STS to protect against high-dose CDDP.

Delayed erosion of intraperitoneal chemotherapy catheters into the bowel. Report of two cases

Erosion of a silastic catheter into the small bowel occurred in two patients who previously had received multiple courses of uncomplicated intraperitoneal (IP) chemotherapy. Although bowel perforation is a recognized complication at the time of Tenckhoff catheter insertion, late erosion of the catheter into the bowel after its use for IP chemotherapy has not been previously reported. Catheter injection with radiographic contrast confirmed the diagnosis, evidence for which included nonspecific clinical findings of intraabdominal infection and pain during chemotherapy infusion.

Purtscher's retinopathy: an unusual association with a complicated malar fracture

A case in which a malar fracture was associated with Purtscher's retinopathy with its accompanying impairment of vision is described. The literature concerning this uncommon condition is reviewed and its aetiology discussed. This case reinforces the importance of visual acuity testing and funduscopy following maxillofacial trauma, not only at presentation but throughout the patient's management.

Effect of cataract extraction on the pupil response to mydriatics

Pupil diameters in the dark, in the light, and after mydriasis with tropicamide+ phenylephrine have been measured in 25 patients before and six months after cataract surgery. The aphakic pupil showed reduced mobility as evidenced by a smaller diameter in the and a larger one in the light. In patients who had intracapsular extraction or extracapsular extraction with intraocular lens implantation the pupils dilated less well than preoperatively. The difference in response to mydriatics is of practical importance in the assessment and treatment of peripheral retinal disorders in aphakic and pseudophakic eyes.

Selective intraperitoneal biochemical modulation of methotrexate by dipyridamole

Dipyridamole increases the toxicity of methotrexate in a concentration-dependent manner. We hypothesized that concurrent intraperitoneal administration of both drugs would result in high peritoneal concentrations with much lower plasma concentrations, permitting a selective increase in the activity of methotrexate against intraperitoneal tumors without enhancing systemic toxicity. Initially, 2.16 mg/m2/d methotrexate and 12 mg/m2/d dipyridamole were delivered together as a constant intraperitoneal infusion for 48 hours. With escalation of chemotherapy, eventually 4.32 mg/m2/d methotrexate was administered for 168 hours. Forty-seven courses were administered to 18 patients. The mean peritoneal to plasma concentration ratios of methotrexate and non-protein bound dipyridamole were 71.6 +/- 34.8 and over 2,300, respectively. Chemical peritonitis was the dose-limiting toxicity. Three patients had some evidence of a response (two with decreasing tumor markers, and the third with a reduction in ascites). We conclude that the drug concentrations are in an appropriate range for selective intraperitoneal biochemical modulation of methotrexate, and that it is feasible to expose tumors confined to the peritoneal cavity to these drugs for long periods of time.

Pharmacologic basis for the use of dipyridamole to increase the selectivity of intraperitoneally delivered methotrexate

Dipyridamole (DP) is an attractive agent with which to increase the selectivity of intraperitoneally delivered methotrexate (MTX). We demonstrated that DP synergistically increased the cytotoxicity of MTX to the human OV 2008 ovarian carcinoma cell line in vitro and that this synergy was highly concentration-dependent. DP did not alter MTX binding in plasma, and vice versa. We found that the two drugs were chemically compatible at concentrations of less than 400 microM, which was well above the concentration needed to make continuous i.p. infusion feasible. The ability of OV 2008 cells to accumulate uridine was used as a bioassay for the in vivo activity of DP. When this drug was infused i.p. at 12 mg/m2 per day, the steady-state peritoneal DP concentrations attained in patients were sufficient for maximal inhibition of uridine uptake, indicating concentrations high enough for synergism with MTX. We found no correlation between total peritoneal protein concentration and either free DP concentration or biologic activity. On the basis of these preclinical and pharmacologic measurements, we conclude that it should be possible to produce selective i.p. biochemical modulation of MTX with DP.

Peripheral carcinoid tumours of the lung: a clinicopathological study

Peripheral carcinoid tumours (PCT) of the lung are a distinct entity. These tumours arise from subsegmental or distal bronchioles, are usually well circumscribed and encapsulated, and contain varying amounts of spindle cells. Their histogenesis is from the Kultchitsky or neurosecretory type of cells. Of 52 patients with carcinoid tumours of the lung, 11 (21.1%) had PCT. The mean age was 60.2 years, 9 out of 11 patients were females, and about two-thirds of tumours were in the left lung (8 out of 13). No patient developed carcinoid syndrome, but three patients had nonspecific respiratory symptoms. Bronchoscopy was not helpful in diagnosing any of these cases. Four patients required a wedge resection of the lung; the other six underwent lobectomy. One patient had tumours detected incidentally at autopsy. Mean tumour size was 2.39 cm (range 1.0-5.0 cm); four tumours were 3.0 cm or larger in diameter. Three cases (27.3%) had regional lymph node metastases, but no systemic metastasis was discovered. Apart from the patient who was discovered to have carcinoid tumours at autopsy, all others are alive and disease-free from 1 to 6 years after surgery.

Isolation, purification and regeneration of protoplasts from Sporotrichum thermophile conidiospores

Protoplasts of uniform size were prepared from mononucleated conidiospores of Sporotrichum thermophile. Conidia were preincubated in glucose yeast extract medium at 45 C for 4 h. The conidia were collected resuspended in buffer containing 0.6 M KCl (as stabilizer), and incubated with Novozyme SP249 and Cellulase CP at 37 C for 6 h. The protoplasts were separated from cell wall fragments and intact conidia by centrifugation over 50% sucrose. The purified protoplasts were regenerated in glucose yeast extract broth after 7 h of incubation at 45 C.

The rabbit renotropic system

Elevated levels of a specific renal growth factor, renotropin, have been associated with spontaneous hypertension. To examine this association more closely, we have undertaken the development of a better assay system to characterize and purify renotropin. Sera from rabbits prior to operation (control) and at a specified time after unilateral nephrectomy (uni) were examined for renotropic activity. Comparing the effects of uni to control sera in the same rabbit, significant stimulation of 3H-thymidine incorporation into the DNA of primary rabbit kidney cultures incubated in D-valine medium to eliminate fibroblast growth was noted: at 3 days postoperatively 73% (n = 13), at 7 days 103% (n = 39), at 10 days 130% (n = 31), at 21 days 101% (n = 24), at 42 days 89% (n = 13). All values were at least P less than 0.01. The stimulatory properties were dose-dependent but reached a plateau at high serum concentrations. Comparing CPM/mg protein in uni/control in different concentrations of sera 7 days postoperatively, uni versus control were 67/44 at 5% v/v, 139/72 at 10% v/v, 261/161 at 20% v/v, and 243/136 at 40% v/v. The renotropic effect of uni sera remained after dialysis in incubation medium and after sera were heated in boiling water for 5 minutes. Renal extracts obtained from growing kidneys 7 days postnephrectomy augmented renotropic activity. Atrial natriuretic factor, ouabain, PGF2 alpha, PGE1, and cAMP did not possess renotropic activity. We conclude that the primary rabbit kidney culture assay for renotropin is highly sensitive and will be an important tool to comprehend the role of renotropin in the pathogenesis of hypertension.

Astigmatism following retinal detachment surgery

Eighty-three patients on whom successful retinal detachment had been performed were studied to note astigmatic changes following surgery. In the majority of cases the errors following such surgery are of no great clinical importance. However, in some situations a high degree of astigmatism may be produced. This study showed that these sequelae are particularly likely after radial buckling procedures, and surgeons favouring these techniques should be aware that astigmatic errors can be induced. The astigmatic errors may persist for several years after surgery.

Plasma copper in foetal malnutrition

Plasma copper in the cord blood of 20 small for gestational age (SGA) term infants was studied. Twenty-five appropriate for gestational age (AGA) term infants were taken as control and another group of 20 preterm AGA infants for comparison. The plasma concentration of copper in term SGA infants was significantly lower than values obtained for the controls, while there was no significant difference from the levels observed in preterm infants. This lowering in the plasma copper levels was possible because of decreased liver synthesis of caeruloplasmin as a result of foetal malnutrition. There was a marked foeto-maternal difference in the plasma copper levels in all three groups which was due to much higher levels of non-diffusible caeruloplasmin in the mothers compared to the neonates.