Specific calcium antagonist binding sites in brain

The binding of the calcium antagonist [3H] nitrendipine ([3H] NDP) to brain and heart is described and the brain site is characterized. The binding is saturable, specific and of very high affinity with KD values of 0.16 nM in brain and 0.21 nM in heart. Our kinetic results are similar to those recently reported by two other groups (1, 2), indicating a saturable, high affinity binding site in brain. In brain the binding sites are enriched in crude nuclear and synaptosomal fractions. The highest levels of binding are seen in the hippocampus, caudate and cerebral cortex with much lower levels in the cerebellum and pons. Calcium has a marked stimulatory effect on [3H] NDP binding at 10(-4) M. Addition of 0.5 mM CaCl2 to EDTA treated membranes nearly doubles the number of binding sites. Of the many drugs and neurotransmitters tested only other calcium antagonists, i.e. verapamil, inhibit binding (IC50 = 250 nM). The inhibition of [3H] NDP binding by verapamil is apparently non-competitive and not complete, suggesting that [3H] NDP binds to several sites, only some of which are inhibited by verapamil. The [3H] NDP binding site is probably a protein since it is very sensitive to trypsin, heat and sulfhydryl reagents.

Characterization of peripheral-type benzodiazepine binding sites in brain using [3H]Ro 5-4864

The binding of [3H]Ro 5-4864 to the peripheral-type benzodiazepine binding site in brain is characterized. The binding is saturable, high-affinity (KD = 1.6 nM), and reversible. The comparison of [3H]Ro 5-4864 and [3H]diazepam binding sites reveals major differences which include the following. There are about one-fourth as many peripheral-type binding sites than central sites in brain. Peripheral sites are present in many extranervous tissues and have a brain regional distribution distinct from that of the central-type receptor. The [3H]Ro 5-4864 binding site also is apparently highly localized in the nuclear membrane in contrast to the central-type receptor, which is synaptosomal. gamma-Aminobutyric acid has no effect on [3H]Ro 5-8464 binding, again in contrast to its marked effect on [3H]diazepam binding. Various putative benzodiazepine receptor ligands, such as purines, beta-carbolines, and kynurenamines, are also inactive as inhibitors of [3H]Ro 5-4864 binding. Blocking the benzodiazepine receptor by photoaffinity labeling decreases [3H]diazepam binding by more than 80% and has no effect on [3H]Ro 5-4864 binding. These results indicate that the peripheral-type benzodiazepine binding site in brain is a separate entity whose physiological function is probably distinct from that of the central-type benzodiazepine receptor.

[3H]nitrobenzylthioinosine binding as a probe for the study of adenosine uptake sites in brain

The binding of the potent adenosine uptake inhibitor [3H]nitrobenzylthioinosine ([3H]NBI) to brain membrane fractions was investigated. Reversible, saturable, specific, high-affinity binding was demonstrated in both rat and human brain. The KD in both was 0.15 nM with Bmax values of 140-200 fmol/mg protein. Linear Scatchard plots were routinely obtained, indicating a homogeneous population of binding sites in brain. The highest density of binding sites was found in the caudate and hypothalamus in both species. The binding site was heat labile and trypsin sensitive. Binding was also decreased by incubation of the membranes in 0.05% Triton X-100 and by treatment with dithiothreitol and iodoacetamide. Of the numerous salt and metal ions tested, only copper and zinc had significant effects on [3H]NBI binding. The inhibitory potencies of copper and zinc were IC50 = 160 microM and 6 mM, respectively. Subcellular distribution studies revealed a high percentage of the [3H]NBI binding sites on synaptosomes, indicating that these sites were present in the synaptic region. A study of the tissue distribution of the [3H]NBI sites revealed very high densities of binding in erythrocyte, lung, and testis, with much lower binding densities in brain, kidney, liver, muscle, and heart. The binding affinity in the former group was approximately 1.5 nM, whereas that in the latter group was 0.15 nM, suggesting two types of binding sites. The pharmacologic profile of [3H]NBI binding was consistent with its function as the adenosine transport site, distinct from the adenosine receptor, since thiopurines were very potent inhibitors of binding whereas adenosine receptor ligands, such as cyclohexyladenosine and 2-chloroadenosine, were three to four orders of magnitude less potent. [3H]NBI binding in brain should provide a useful probe for the study of adenosine transport in the brain.

Ontogeny of adenosine binding sites in rat forebrain and cerebellum

The metabolically stable adenosine analogue N6-cyclohexyl [3H]adenosine ([3H]CHA) was used to label adenosine receptors in rat forebrain and cerebellum during development. [3H]CHA binding develops rather slowly, with adult binding levels obtained at 24 days in cerebellum and later in the forebrain. Ontogenic profiles in both areas are consistent with the onset of neuronal differentiation. High and low affinity sites appear to develop in parallel, since Scatchard analysis in forebrain tissue obtained from 5-day-old animals revealed both binding sites.

Leukocyte-derived interferon (alpha) in human breast carcinoma. The American Cancer Society phase II trial

A multi-institutional trials program was initiated to define the effects of interferons in disseminated human breast carcinoma. Interferon alpha, prepared from buffy coats, was administered intramuscularly at 3 x 10(6) U daily for an initial period of 28 days. Of 23 patients who entered the program, five had an objective partial response of 92 days mean duration at diverse sites of involvement. Patients who responded were significantly older (p = 0.05) than nonresponders. Dose escalation in eight patients did not result in any clear evidence of additional responses. Major toxicities were fatigue, anorexia with weight loss, and reversible leukopenia (less than 3.5 x 10(9) leukocytes/L in 16 patients). Natural killer cell and antibody-dependent cell-mediated cytotoxicity were significantly (p less than 0.05) enhanced 48 hours after interferon administration began but subsequently declined despite continued therapy. Serum beta 2-microglobulin concentration increased on day 15 (p less than 0.05) and remained significantly elevated on day 22 (p less than 0.005). Peak interferon titers (mean, 62 U) occurred 6 hours after interferon was started, varied widely between patients, and were higher and more persistent with dose escalation. Once an optimal dose is defined, prospectively randomized trials will define what role interferons may have in systemic therapy of breast carcinoma.

Protection against pneumococcal sepsis in splenectomized rats by implantation of splenic tissue into an omental pouch

Clinical and laboratory studies have documented high susceptibility to pneumococcal infection in asplenic humans and animals. Surgeons have stressed the need to preserve the spleen when possible to maintain host resistance. It has been suggested that autotransplantation of splenic tissue might be a method of providing host resistance when total splenectomy is necessary. However, previous studies of rats have failed to demonstrate any protective effect of autotransplanted spleen. This study evaluates the effect of splenic autotransplantation into the omental pouch on pneumococcal infections in rats. Healthy, young Sprague-Dawley rats were divided into three groups of 40 each. Group I served as anesthetized sham-operated controls. Group II had a splenectomy. Group III had a splenectomy with autotransplantation of two slices of spleen 3 mm thick into surgically created omental pouches. Sixteen weeks after surgery, all animals were inoculated with Streptococcus pneumoniae type 25 in a dose of 2 X 10(7) (LD50 for splenectomized rats). Fourteen days after inoculation, all group III survivors were killed and the transplants were removed for examination. Group I had 100% survival rate following bacterial inoculation. There was a significant difference in survival rate between group II (56%) and group III (89%) (P less than 0.001). Pathologic examination of group III demonstrated hyperplastic regeneration of splenic tissue within the omental pouch. Rats bearing reimplanted splenic tissue in an omental pouch were protected against pneumococcal peritonitis.

Effects of caffeine and theophylline on adenosine and benzodiazepine receptors in human brain

The binding of various adenosine receptor ligands and of [3H]diazepam, as well as their inhibition of methylxanthines, have been studied in human brain cerebral cortex membranes. Caffeine and theophylline competitively inhibit binding of [3H]cyclohexyladenosine, [3H]diethylphenylxanthine, [3H]phenylisopropyladenosine and [3H]diazepam. Both caffeine and theophylline are more potent as inhibitors of adenosine receptor ligand binding compared to [3H]diazepam binding. Theophylline was more potent than caffeine in its ability to compete with adenosine receptor ligand binding while the reverse was true for [3H]diazepam binding. The meaning of these results for the mode of action of methylxantine is discussed.

Differential effects of GABA on peripheral and central type benzodiazepine binding sites in brain

The binding of the clinically inactive benzodiazepine [3H]RO-5-4864 to brain membranes was investigated. The peripheral type benzodiazepine binding site was demonstrated in brain with an apparent Kd of 1.6 nM and a Bmax of 20 fmol/mg protein. Monophasic Scatchard plots indicate a homogenous population of a high affinity sites. The major inhibitory transmitter GABA, has no effect on [3H]RO-5-4864 binding to extensively wash brain membranes. The peripheral type benzodiazepine binding site found in brain is therefore not modulated GABA.

Characterization of adenosine receptors in brain using N6 cyclohexyl [3H]adenosine

The presence of distinct binding sites for adenosine in both the CNS and PNS has been proposed in numerous studies. The recent availability of stable adenosine analogues such as cyclohexyladenosine, 2-chloroadenosine and diethylphenylxanthine has made the characterization of such a receptor feasible. In the present report the binding of N6 cyclohexyl [3H]adenosine ([3H]CHA) to rat brain synaptosomal membranes is characterized. [3H]CHA binding is saturable and exhibits a biphasic kinetic saturation profile characteristic of 2 binding sites. The high affinity site has a Kd of 0.7 nM and the low affinity site 2.4 nM. The respective Bmax values are 230 and 120 fmol/mg protein in fat forebrain. The highest density of binding sites is found in the hippocampus and subcellular distribution studies indicate that the [3H]CHA site is predominantly synaptosomal. [3H]CHA binding is highly dependent in the presence of adenosine deaminase since only 30% of the binding capacity is observed in synaptosomal membranes not treated with this enzyme. Of the many cations and anions tested only copper and zinc have effects on [3H]CHA binding. Both metals are potent inhibitors of binding with copper having an IC50 of 30 microM and zinc 150 microM. Sulfhydryl reducing and alkylating agents also inhibit binding indicating that the binding site is a sulfhydryl-dependent protein.

Benzodiazepines are weak inhibitors of [3H]nitrobenzylthioinosine binding to adenosine uptake sites in brain

Saturable, specific, high affinity binding of the potent adenosine uptake inhibitor [3H]nitrobenzylthioinosine ([3H]NBI) to brain membranes has been demonstrated. In an effort to test the hypothesis that benzodiazepine action may be due to the inhibition of adenosine uptake, the inhibition of [3H]NBI binding by diazepam, clonazepam and chlordiazepoxide was tested. The benzodiazepines are very weak inhibitors of [#H]NBI binding, having IC50 values several orders of magnitude above their therapeutic levels.

A comparative evaluation of vaginal, cervical and peritoneal flora in normal, healthy women: a preliminary report

Twelve healthy women undergoing laparoscopic tubal sterilization were studied. Specimens were obtained for culture of aerobic and anaerobic bacteria, Mycoplasma hominis, Ureaplasma urealyticum, and Chlamydia trachomatis. The sites cultured included cul-de-sac (through a laparoscope), cul-de-sac (by transvaginal culdocentesis), the vaginal wall, and the endocervical canal. Anaerobic bacteria were isolated from the peritoneal cavity of three (25%) of the subjects. These isolates included B. melaninogenicus from two specimens obtained by laparoscope from the peritoneal cavity and from two peritoneal specimens obtained by culdocentesis. The data suggest that the peritoneal cavity of normal healthy women is not always sterile. We did not encounter contamination of transvaginal culdocentesis specimens with vaginal flora.

Effect of estrogen and progesterone on cellular replication of human breast tumors

A total of 54 infiltrating carcinomas of the breast were studied for estrogen receptor concentration in the tumor cytosol and thymidine-labeling indexes. The results showed that there was no significant difference in the level of thymidine-labeling index between 22 primary and 32 metastatic breast cancers. No significant association between the levels of thymidine-labeling index and the presence or absence of estrogen receptors was observed. The effect of "physiological" doses of estrogen and progesterone on cell proliferative activity was studied by the level of thymidine-labeling indexes in the tumor cells in 10 patients with multiple skin and s.c. metastases. Tumor biopsies were performed for labeling indexes both before and after hormonal treatment. The results showed that physiological doses of estrogen and progesterone induced a significant rise in thymidine-labeling index within 3 days after hormonal treatment in seven of the 10 tumors. Of the seven tumors that showed a rise in thymidine-labeling index, three were estrogen receptor positive and four were estrogen receptor negative. Of the three nonresponsive tumors, one was estrogen receptor positive and two were estrogen receptor negative. The study suggests that estrogen and progesterone can induce cell replication in both estrogen receptor-positive and -negative tumors.

Preservation of splenic function by autotransplantation of traumatized spleen in man

Splenectomy is known to increase the risk of overwhelming bacterial infection. Characteristically, there is a decrease in immunoglobulin IgM, properdin, and T-lymphocytes; impaired primary antibody response to antigen challenge; an altered opsonic function; and a tuftsin deficiency. Because the spleen is important in host defense, preservation of traumatized splenic tissue has been advocated. Splenic autotransplantation has been suggested as a method of preserving function, and this concept is supported by experiments in animals. The present study describes autotransplantation of the traumatized spleen in human beings for the preservation of splenic function. Four patients operated on for blunt abdominal trauma required total splenectomy for hemostasis and were deemed suitable candidates for autotransplantation of the splenic tissue. In each, thinly sliced segments of spleen (roughly 20 gm.) were placed in a previously fashioned omental pouch. All patients survived without complications. Postoperative studies included blood and platelet counts, cell morphology, determination of serum immunoglobulin levels, and splenic scans. Four weeks postoperatively, Howell-Jolly bodies and target cells had disappeared from the red cells. Platelet counts returned to normal range. Initially low IgM and C3 complement levels increased to normal. Scans at 8 weeks confirmed the presence of functioning splenic tissue. Autotransplantation of the spleen is a safe method for preserving splenic function when total splenectomy is mandatory for hemostasis.

Sonographic imaging of the glycogen stage of the fetal choroid plexus

At 8-22 weeks gestation, the lateral ventricular choroid plexus swells with glycogen deposits, which are thought to be an important source of anaerobic energy for a relatively hypovascular stage of brain development. Sonographic images during this phase demonstrate enlarged and echogenic ventricles, accounting for up to 80%-90% of the cerebral axial dimension in the earliest gestations studied. This increased echogenicity may be due to these glycogen stores. Because a rapid but sonographically definable decrease in the relative size of these structures occurs, routine imaging for the presence and character of the choroid plexus might prove to be a useful parameter in fetal examination.

Tardive dyskinesia with Tourette-like syndrome

This is a single case study of a 22 year old Japanese-Canadian woman who developed schizophrenia, was treated with ECT and several successive neuroleptics and subsequently, three years later, developed a tardive dyskinesia syndrome in association with a behavioral change resembling Gilles de la Tourette disease. This combined syndrome lasted seven months. After neuroleptics were withdrawn, the syndrome diminished in severity and disappeared after four months. Since both tardive dyskinesia and Tourette's disease are thought to be caused by relative overactivity or supersensitivity of the dopamine system, their reversible appearance after long term dopamine receptor blockade by neuroleptics can be expected in susceptible individuals.