Fine structural studies of cholecystokinin-8-like immunoreactive neurons and axon terminals in the nucleus of tractus solitarius of the rat

Cholecystokinin (CCK)-8-like immunoreactive structures in the nucleus of tractus solitarius (NTS) were studied by using the peroxidase-antiperoxidase (PAP) immunohistochemical method. Immunoreactivity was localized in cell bodies and nerve fibers. The perikarya were oval or fusiform (average length 13 micron) and were mostly located in the dorsal half of the medial subnucleus of the NTS at the level of the area postrema (AP). One to three straight immunoreactive dendritelike processes emerged from the perikarya. Neurons that had first been identified under light microscopy were also studied by electron microscopy. Each neuron had a moderate amount of cytoplasm and an oval or elongated nucleus that was eccentrically located in the soma. A few synaptic inputs were found on the CCK immunoreactive perikarya, while a moderate number were seen on both proximal and distal dendrites. These neurons received both asymmetrical and symmetrical synaptic inputs. The immunoreactive dendrites were most frequently in asymmetrical synaptic contact with nonreactive boutons (max. 2.7 micron in diameter) containing fairly densely packed, small round vesicles. CCK immunoreactive boutons located in the NTS at the level of the AP were analyzed using electron microscopy; these boutons formed asymmetrical synaptic contact with other neuronal elements. Their postsynaptic targets were immunoreactive and nonreactive perikarya and dendrites. These data suggest that CCK-containing afferents might affect the neurotransmission of heterogenous types of solitary neurons.

Changes of the hepatic CT absorption value in hemodialysis patients

The effect of hemodialysis on the CT absorption value of the liver was examined in 14 hemodialysis patients. In the high ultrafiltration group [10 patients with a weight loss of -1.7 to -3.5 (2.9 +/- 0.6) kg], the hepatic CT absorption value increased from 49.6 +/- 7.0 to 58.7 +/- 8.7 Hounsfield units (p less than 0.001) during hemodialysis. The increase in hepatic CT absorption value during dialysis correlated with the weight loss (p less than 0.001, r = 0.798). A 5.3% body weight loss by ultrafiltration resulted in an 18.5% increase in the CT absorption value of the liver. This study suggests that one should be careful in making an early diagnosis of hepatic disease, especially hemosiderosis, in hemodialysis patients based on the hepatic CT absorption value because it is affected by hemodialysis.

Cholecystokinin-8-like immunoreactivity in the pre- and post-central gyri of the human cerebral cortex

Cellular localization of cholecystokinin-8-like immunoreactive (CCK-IR) structures in the pre- and post-central gyri of the human cerebral cortex was examined by indirect immunofluorescence. CCK-IR was localized mostly in perikarya of non-pyramidal cells such as multipolar, bitufted and bipolar cells, and to a lesser extent in medium and small pyramidal cells. CCK-IR fibers were also observed in these gyri, predominantly in layers I and III.

Cholecystokinin-8-like immunoreactive neuron pathway from the supramammillary region to the ventral tegmental nucleus of Gudden of the rat

The existence of a pathway from the supramammillary region (SM) to the ventral tegmental nucleus of Gudden (NTV) containing cholecystokinin-8 (CCK)-like immunoreactive (CCKI) structures was demonstrated by experimental manipulations in the rat. Destruction of the SM resulted in the disappearance of CCKI fibers in the NTV.

Distribution, origin, and fine structures of cholecystokinin-8-like immunoreactive terminals in the nucleus ventromedialis hypothalami of the rat

The distribution, origin, and fine structures of cholecystokinin-8-like immunoreactive ( CCKI ) fibers in the nucleus ventromedialis hypothalami (vm) of the rat were examined using immunohistochemistry. CCKI fibers were moderately concentrated in the ventrolateral part of the vm, decreasing in number dorsomedially. However, no CCKI cells were seen in the vm even in colchicine-treated rats. In addition, the destruction of the lateral part of the nucleus parabrachialis dorsalis (pbd) where numerous CCKI cells were seen resulted in a marked decrease in CCKI fibers in the vm on the operated side. Electron microscopic observations revealed that CCKI terminals make synaptic contact with soma, spine, and the proximal segment of the dendrite. The neurons making synaptic contact with the CCKI fibers had moderately electron-lucent cytoplasm. These findings suggest that the CCKI fibers in the vm originate from CCKI cells in the lateral part of the pbd and directly influence the vm neurons.

Ontogeny of cholecystokinin-8 containing neuron system of the rat: an immunohistochemical analysis--II. Lower brain stem

The ontogeny of the cholecystokinin-8 neuron system in the lower brain stem of the rat was investigated by means of indirect immunofluorescence. Cholecystokinin-8-like immunoreactive structures first appeared in the primordium of the ventral tegmental area, ventral tegmental nucleus of Gudden and the area lateral to the superior central nucleus of the fetus on gestational day 17. Although cholecystokinin-8-like immunoreactive structures appeared gradually in various lower brain stem areas from this day, and developed markedly from postnatal day 6, thereafter, the ontogeny of cells and fibers was different. In general, the fibers increased in number as the rats grew and reached the maximum in adulthood, whereas the cells reached a maximum number between postnatal days 6-12, after which they decreased in number. Colchicine treatment, however, demonstrated the presence of cholecystokinin-8-like immunoreactive cells in various areas of the lower brain stem. These findings suggest that the cholecystokinin-containing neuron system is active in the adult and that cholecystokinin-containing cell somata cannot store a sufficient amount of the peptide for visualization in the absence of colchicine. Thus, it might be concluded that cholecystokinin may play an important role in the brain function of the adult as a neurotransmitter or neuromodulator, though its exact function is now open to discussion.

Plasma cholecystokinin responses after ingestion of liquid meal and intraduodenal infusion of fat, amino acids, or hydrochloric acid in man: analysis with region specific radioimmunoassay

A highly sensitive and precise radioimmunoassay system for plasma cholecystokinin (CCK) was developed with the anti-CCK-8 specific antiserum which raised against N-terminal amino acids residue of sulfated CCK-8 and reacted with CCK-8, CCK-33, and CCK-39 but not with gastrin and its related peptides. Mean concentration of the fasting plasma CCK determined with this method using CCK-8 as standard was 12.9 +/- 5.9 pg/ml in normal subjects (n = 26), and in patients with hepatic cirrhosis it was significantly higher (36.7 +/- 16.9 pg/ml, n = 9, p less than 0.01) than in normal subjects. In six young healthy volunteers, intraduodenal infusion of fat caused a significant increase (p less than 0.05) of plasma CCK from a basal level of 8.0 pg/ml to a peak of 43.0 +/- 12.0 pg/ml at 20 min after starting of infusion. In the same subjects, a significant increase of plasma CCK was also observed by amino acids infusion, but no elevation of plasma CCK level was found during intraduodenal acidification.

Ontogeny of cholecystokinin-8-containing neuron system of the rat: an immunohistochemical analysis. I. Forebrain and upper brainstem

Ontogeny of the cholecystokinin-8 (CCK) neuron system in the forebrain and upper brainstem of the rat was investigated by means of indirect immunofluorescence. CCK cells and fibers first appeared in the developing ventral tegmental area and in the primordium of the medial forebrain bundle, respectively, at gestational day 15 (12-14-mm embryos). From that time, CCK cells appeared in various areas of the forebrain and upper brainstem until birth and reached the maximum content at postnatal day 10. After postnatal day 10, although CCK cells tended to decrease slightly in number, colchicine treatment in the adult rats brought out numerous CCK cells in the same areas. In contrast, although CCK fibers developed only slightly during the fetal period, marked development was seen after birth, particularly between postnatal days 5 and 10. After that time, as the rats grew, CCK fibers continued to increase in number and formed a meshwork of varying density in various areas of the forebrain and upper brainstem.

The distribution of cholecystokinin octapeptide-like structures in the lower brain stem of the rat: an immunohistochemical analysis

The distribution of immunoreactive cholecystokininoctapeptide (CCK-8)-like structures in the lower brain stem of the rat was investigated using indirect immunofluorescence. In addition to the well known immunoreactive CCK-8-like containing cell groups such as those in the ventral tegmental area, substantia grisea centralis of the mesencephalon, and n. linealis rostralis, the present study demonstrated a much wider distribution of immunoreactive CCK-8-like cells in the lower brain stem, i.e. those in the inferior colliculus, n. parabrachialis colliculi posterioris, lateral lemniscus, lateral parabrachial area, n. centralis superior, nucleus of group O, pontine substantia grisea centralis, n. tractus solitarii, area postrema, n. tractus spinalis nervi trigemini and reticular formation just dorsal to the inferior olivary complex. We also demonstrated an extensive network of immunoreactive CCK-8-like fibers in various areas of the lower brain stem, including the auditory system, visual system, viscerosensory area, parabrachial nucleus, dorsal and ventral tegmental nuclei, and interpeduncular nucleus. The possible importance of CCK is briefly discussed.

Production of rabbit antibody specific for amino-terminal residues of cholecystokinin octapeptide (CCK-8) by selective suppression of cross-reactive antibody response

Antibody specific for the amino-terminal region of cholecystokinin octapeptide (CCK-8) was generated in a highly reproducible way in New Zealand white rabbits by a novel immunization procedure which involves immunization with CCK-8 peptide conjugate coupled with keyhole limpet hemocyanin (KLH) and inhibiting cross-reacting antibody formation by treatment of the animals with a potent tolerogenic conjugate of beta-alanyl-tetragastrin and a copolymer of D-glutamic acid and D-lysine (D-GL). The antisera thus produced specifically react with an amino-terminal region of CCK-8 but not with the non-sulfate form of CCK-8, nor with the carboxy-terminal region which shares a cross-reactive determinant among gastrin and cholecystokinin-related peptides (caerulein, CCK-4, CCK-8, CCK-33 and CCK-39). The antisera produced by this method allowed us to measure specifically CCK in extracts from tissue such as duodenum containing gastrin and CCK at comparable levels.

Proliferative pattern of seminal vesicle cells and the production of testosterone and 5 alpha-androgens from birth to adulthood in mice

Proliferation of seminal vesicle cells and the concentration of testicular and serum androgens (testosterone and 5 alpha-androgens) from birth to adulthood were investigated in mice. The weight of the seminal vesicles increased significantly from day 0 to day 10 after birth (approximately 0.1-1 mg), remained nearly constant in the next 10 days, and increased again (1-50 mg) thereafter. As an index of cell proliferation, two distinct peaks of 5-[125I]iodo-2'-deoxyuridine ([125I]IdUrd) uptake by the whole seminal vesicles were found at days 8 and 30. Types of proliferating cells examined by autoradiography after injection of [3H]thymidine were partially testis-dependent fibromuscular and epithelial cells in the first peak and largely testis-dependent epithelial cells in the second peak. The [125I]IdUrd uptake values found around day 20 and after day 40 were similar to those in neonatally castrated mice. Concentrations of testicular and serum androgens were relatively high on days 8, 30, 35, 40, and 60 (0.2-0.7 ng/mg tissue and 1.3-2.2 ng/ml, respectively) but were very low on day 18 (0.02 ng/mg tissue and 0.4 ng/ml). These findings lead to the hypothesis that androgens secreted from neonatal and prepubertal mouse testes play a major role in the proliferation of seminal vesicle cells and that the quiescent interval of androgen secretion and action occurs around the 20th day after birth in mice.

A novel immunization procedure for production of anti-cholecystokinin-specific antiserum of low cross-reactivity

An anti-cholecystokinin octapeptide (CCK-8) antibody without cross-reactivity with pentagastrin, whose amino acid sequence is identical with the carboxy-terminal portion of CCK-8, was produced by immunization with CCK-8-keyhole limpet hemocyanin and injection of a conjugate of pentagastrin and a copolymer of D-glutamic acid and D-lysine to inhibit production of antibody cross-reacting with pentagastrin.

A novel immunization procedure involving pretreatment with cross-reacting steroid conjugated to a copolymer of D-glutamic acid and D-lysine for production of low cross-reactive antisera

Anti-testosterone and anti-5 alpha-dihydrotestosterone antisera have been produced by pretreatment of mice with a cross-reacting steroid coupled to a copolymer of D-glutamic acid and D-lysine to inhibit production of cross-reacting antibodies before immunization with the specific steroid conjugated to a protein. 15 beta-Carboxyethylmercapto derivatives were used as haptens. The cross-reactivities of the anti-testosterone and anti-5 alpha-dihydrotestosterone antisera with 5 alpha-dihydrotestosterone and with testosterone were 0.49 and 13.5%, respectively.

Noninvasive transcutaneous oxygen pressure diagnosis of reversed ductal shunts in cyanotic heart disease

Double-site transcutaneous oxygen pressure (tcPO2) monitoring was carried out in 24 infants with cyanotic heart disease and in 12 acyanotic "control" infants. The tcPO2 values were recorded continuously as ambient forced inspiratory oxygen (FIO2) was varied from 0.21 to almost 1.0. The recordings obtained in the cyanotic infants could be grouped in one of four patterns, each of which correlated closely with the altered hemodynamic characteristics of heart disease. These data confirm the value of this noninvasive technique for hemodynamic and anatomic diagnosis of cyanotic heart disease, especially in cases with arotic arch anomalies with reversed ductal shunts.

Anti-testosterone antisera produced in mice of different strains and sexes

Specific anti-testosterone antiserum was obtained from mice of the strain C57B1/6. Testosterone 3(O-carboxymethyl)oxime-keyhole limpet hemocyanin conjugate was administered to male and female mice of the strains C57B1/6 (H-2b), DBA/2 (H-2d), (C57B1/6 x DBA/2)F1, (H-2b/d), and AKR (H-2k). Antisera obtained from male and female C57B1/6 mice were more specific for testosterone than those from the other strains, and the cross-reaction with 5alpha-dihydrotestosterone was 25.0 and 29.2%, respectively. The titer of antiserum from C57B1/6 mice was the highest and that of antiserum from DBA/2 mice was the lowest. On the other hand, the titer of antiserum from the female was higher than that of antiserum from the male in each strain. These results indicate that the mouse strain and sex differences are important factors for antibody formation from challenged antigen.

Enzyme immunoassay of serum testosterone

An enzyme immunoassay of serum testosterone using the testosterone-glucoamylase complex is described. Testosterone was estimated by the enzyme immunoassay after extraction with hexan: ether (4:1) for serum from men and additional thin layer chromatographic step for serum from women. The within and between assay errors, measured as the coefficient of variation were 11.1 percent (n=8) and 12.0 percent (n=12). The sensitivity of this assay was 0.25 ng. The mean testosterone concentration (+/- SD) in 19 normal men and 4 normal cycling women were 5.3 +/- 1.8 and 0.52 +/- 0.12 ng/ml, respectively. The level of testosterone found by the present assay compared favorably with those obtained by other methods.

Enzyme immunoassay of testosterone using the testosterone-glucoamylase complex

A highly sensitive, reproducible method was established for enzyme-coupled immunoassay of testosterone, involving coupling of testosterone to glucoamylase [EC 3.2.1.3] with a water-soluble coupling reagen carbodimide. No enzyme activity was lost during this coupling procedure. The sensitivity of the method was comparable to that of competitive protein binding assay.