A rapid in vitro labeling index method for predicting response of human solid tumors to chemotherapy.

A rapid autoradiographic technique for measuring the [3H]thymidine-labeling index of human solid tumors has been adapted to assess the effect of anticancer drugs in vitro. The drugs tested were present unchanged or as metabolites in serum obtained from patients immediately post-treatment. In 15 patients, the drugs tested in vitro were also given in vivo. Tumor-labeling index fell significantly in 5 of 6 patients who were later found to have objective clinical response. Tumor-labeling index did not change significantly in 8 patients and rose significantly in 1 of 9 patients who lacked clinical response. If confirmed, this in vitro test may prove to be a useful method of predicting responsiveness of human solid cancers to chemotherapeutic agents.

Correlation of DNA distribution abnormalities with cytogenetic findings in human adult leukemia and lymphoma.

Pulse cytophotometric analysis of bone marrow cells from 175 patients with leukemia or lymphoma showed abnormalities of cellular DNA distribution in 29 patients for an overall incidence of 16.6 percent. Comparative standard cytogenetic examination indicated that high-degree chromosomal aberrations (less than or equal to 44, greater than or equal to 53 chromosomes) can generally be detected on DNA histograms, whereas patients with diploid, pseudodiploid, 45-hypodiploid, and 47-hyperdiploid abnormalities usually escape recognition by this technique. There were 11 patients with normal diploid or near-diploid karyotypes exhibiting marked DNA deviations; this discrepancy may reflect lack of proliferation of some leukemic clones which is a prerequisite for cytogenetic identification.

Serial labeling index determination as a predictor of response in human solid tumors.

A rapid method for determining labeling indices in solid tumor specimens, tumor-induced effusions, and tumor-bearing bone marrows was utilized in 116 patients. Of these, 48 patients were studied pre- and postchemotherapy. The magnitude of a significant change in labeling index (LI percent) was determined statistically. Of the 48 patients studied serially, 42 were studied 17 days or less following completion of their chemotherapy. In 26 patients without a significant change in tumor LI percent, there was no subsequent clinical response to chemotherapy. Three additional patients in this group are inevaluable at present. In 11 patients, there was a significant fall in tumor LI percent following chemotherapy. Seven of these had a 50 percent or greater regression of demonstrable disease, one patient had definite tumor effect but the effect was not a partial response and three patients were not evaluable for clinical response. In two patients there was a significant increase in tumor LI percent and the patients had rapid tumor progression and death. Predictions derived from serial study of the LI percent by this method correlate significantly with subsequent behavior of the tumors tested following chemotherapy and may prove clinically useful in making decisions about when or whether to change therapy.

Galactose uptake by human platelets in vitro.

Galactose transport by human platelets has been studied by measuring the cellular accumulation of the radiolabeled sugar during brief periods of suspension in varying concentrations of galactose. Weighted least-squares regression curves fitted to the measurements (initial velocity versus galactose concentration) indicate that a kinetic model with two saturable components is statistically more consistent with the data than a model based upon a single process (P less than 0.001). For the two-component model Km1 = 0.29 mM, V1 = 1.2 mmol/min per 10(15) platelets, Km2 = 46 mM, V2 = 117 mmol/min per 10(15) platelets. The fact that galactose metabolites did not accumulate during the initial phase of uptake indicates that the uptake process is not mediated by enzymatic catalysis. Surface binding also appears inadequate to explain the uptake. The most likely basis for the kinetic data, therefore, is membrane transport. The kinetics are consistent with transport by coexistent membrane structures as well as with transport by a single structure manifesting negative cooperativity.

Cytochalasin inhibition of hexose transport by platelets.

Previously we described a two-transporter model (T1, T2) for galactose uptake by platelets (Horne, M.K. and Hart, J.S. (1986) Biochim. Biophys. Acta 856, 448-456). In the current work we have sought corroborative evidence for this model by studying the effects of cytochalasins on this transport system. Of the various cytochalasins tested, cytochalasin B was the most potent inhibitor (I) of galactose transport, whereas cytochalasin A was less inhibitory and dihydrocytochalasin B and cytochalasin E had no inhibitory effect. The same order of potency was observed for the inhibition of L-glucose diffusion into platelets. The mechanism of cytochalasin B inhibition was investigated in detail. Inhibition of T1 was competitive and required a higher concentration of cytochalasin B (Ki1 approximately 1.7 microM) than inhibition of T2, which was of a mixed type (Ki2 approximately 0.8 microM). The effect of cytochalasin B on T2 could be accounted for by a membrane alteration which enhanced the affinity of the transporter for galactose while simultaneously preventing passage of the TSI complex into the cell. Since a similar effect on membrane permeability would also explain cytochalasin B inhibition of L-glucose diffusion, it is hypothesized that cytochalasin B binds to a membrane structure shared by T2 and the passage for L-glucose. The differences in cytochalasin B sensitivity and mechanism of inhibition manifested by T1 and T2 support our original hypothesis that galactose is indeed transported by kinetically distinct agencies and suggest that these may be physically distinct as well.

Efficacy of bedtime NPH insulin with daytime sulfonylurea for subpopulation of type II diabetic subjects.

Although insulin and sulfonylureas often have additive clinical effects when used in combination for type II (non-insulin-dependent) diabetes, these results are variable and a clinical role for this approach is not yet established. This study tests the efficacy of a specific combined regimen for a subpopulation of patients with a randomized double-masked placebo-controlled crossover design and under conditions similar to those of clinical practice. Twenty subjects with limited duration (less than 15 yr) type II diabetes who were moderately obese (less than 160% ideal wt) and proved imperfectly controlled on 10 mg glyburide twice daily completed two 4-mo crossover protocols, comparing a single injection of NPH insulin in the evening plus 10 mg glyburide in the morning with insulin plus placebo. Insulin dose was adjusted by experienced endocrinologists seeking the best glycemic control consistent with safety. All subjects had glycosylated hemoglobin values less than or equal to 150% of the control mean on combined therapy, and combined therapy was superior to insulin alone (fasting plasma glucose 8.0 +/- 0.3 vs. 11.1 +/- 0.6 mM, P less than .01; glycosylated hemoglobin 9.8 +/- 0.1 vs. 10.6 +/- 0.2%, P less than .01). Despite greater weight gain on combined therapy, blood pressure and plasma lipid concentrations were the same on the two regimens. These results suggest this simple regimen offers another option, besides multiple injections of insulin, for patients of this kind who are unsuccessful with a sulfonylurea or a single injection of insulin alone.

A preliminary study of polyamines in the bone-marrow plasma of adult patients with leukemia.

Polyamines (mainly putrescine, spermidine, and spermine) whose biosynthesis is a prerequisite for cell proliferation, are potential indicators of malignant growth. To investigate the mechanism of alterations of polyamine levels in physiological fluids in human cancer, polyamine levels of bone-marrow plasma from adult patients with leukemia were studied. Significant correlations were observed between bone-marrow cellularity and spermidine, between peripheral white blood cell counts and spermidine and spermine, and between absolute blast count and spermidine and spermine among untreated patients with acute leukemia. Untreated patients with chronic leukemia showed significantly elevated levels of polyamines relative to untreated patients with acute leukemia, indicating a higher turnover of bone-marrow cells in chronic leukemia than in acute leukemia. Chemotherapy-treated patients with acute leukemia who were in remission or who did not respond to the agent showed low polyamine levels. Patients who showed a destruction of tumor cell during chemotherapy gave high levels of polyamines. Overall, these studies indicate that elevated polyamine levels are markers of cell death.

A physician's perspective on the advantages of home medical care: the other side of case management.

As medical costs increase, alternatives to hospitalization for medical care must be sought. Patient care provided through outpatient clinics and home settings offers such alternatives. Intravenous antibiotics, fluids, blood, total parenteral nutrition, chemotherapy, and pain management as well as dialysis may now be given in the comfort of the patient's home. Overall, home services may save 30% to 50% in costs compared with costs for the same service provided in the hospital. The major savings comes from removing the charge for the hospital room.

Utilization of galactose by human platelets in vitro.

The extent to which platelets can metabolize galactose has been unknown. We have studied this question by incubating platelets with radiolabeled galactose for periods of time and analyzing the cells for radioactive metabolites. The sugar was observed to accumulate quickly in cells isolated by filtration. Within seconds at room temperature, galactose metabolites were detectable by thin-layer chromatography, and within 20 minutes at 37 degrees C, radioactivity appeared in trichloroacetic acid (TCA) precipitates of the suspensions. The TCA-precipitable radioactivity was degraded by alpha-amylase as well as by protease. However, the TCA-soluble material released by protease digestion had an elution volume on Sepharose CL-4B too small for glycopeptides and in addition was degraded by alpha-amylase. The majority of the galactose metabolized by platelets, therefore, becomes incorporated into glycogen, rather than glycoprotein. The reversibility of the galactose metabolic pathway was demonstrated by the addition of an excess of the unlabeled sugar to the labeled platelets and by the effect of thrombin and collagen on the TCA-precipitable radioactivity.

Changes in red blood cell volume on fixation in glutaraldehyde solutions.

Light scattering (nephelometry) was used to determine directly the change in volume of red blood cells immersed in a variety of buffer and fixative solutions. Cells immersed in saline or phosphate buffer solutions showed a change in volume that reflected the osmolarity of the solution, shrinkage taking place in hypertonic solutions and swelling and haemolysis occurring in strongly hypotonic solutions. On the other hand, while there was considerable shrinkage in hypertonic glutaraldehyde solutions, swelling was more restricted and haemolysis was prevented in the weaker glutaraldehyde solutions. Thus, while glutaraldehyde exerts a definite osmotic effect on cells in fixative solutions, the magnitude of this effect seems to be limited by its direct action as a fixative.