Expression of phenylethanolamine N-methyltransferase in sympathetic neurons and extraadrenal chromaffin tissue of chick embryos in vivo and in vitro

Previous studies suggested the existence of two populations of cells in the mammalian sympathetic nervous system which differ in their ability to express phenylethanolamine N-methyltransferase (PNMT), the enzyme which specifically subserves the biosynthesis of epinephrine: (1) sympathoblasts and their progeny, the noradrenergic sympathetic neurons (PNMT negative); and (2) phaeochromoblasts , the precursors of the adrenergic cells of the adrenal gland and extra-adrenal chromaffin tissue (PNMT-positive). We sought to determine whether similar differences between sympathoblasts and phaeochromoblasts exist in other classes of vertebrate embryos. Using immunohistochemical and biochemical techniques to assay PNMT in sympathetic organs, we have found that chick embryo paravertebral ganglia contain PNMT activity both in vivo and in vitro. In vitro PNMT immunostaining was detected in principal neurons as well as in small process bearing neurons similar to mammalian SIF cells. In vivo, cells containing PNMT were seen not only in the adrenal gland, but also in other sympathetic structures such as the extra-adrenal chromaffin tissue and, unexpectedly, also in some cells of the kidney. Tyrosine hydroxylase, the first enzyme of the catecholamine (CA) biosynthetic pathway, was found in the same cells which could be stained with PNMT antibodies as well as in the sympathetic ganglia. Thus, we conclude that in contrast to the rat, chick sympathoblasts share with phaeochromoblasts the property of expressing all the CA enzymes, including PNMT.

Acne fulminans with arthritis in identical twins treated with isotretinoin

Images

Distribution of catecholamine neurons in the hypothalamus and preoptic region of mouse

The distribution and morphology of cells containing tyrosine hydroxylase (TH) were mapped by using the immunoperoxidase technique in the hypothalamus and preoptic area in two strains of mouse, CBA/J and BALB/cJ. On the basis of rostral-caudal contiguities between cell aggregates, hypothalamic preoptic neurons were subdivided into three arbitrary groups: (1) dorsal, (2) intermediate, and (3) ventral. New or more prominent collections of TH cells were observed, and in some regions, cells were more complexly organized than originally described. In the dorsal group, a rostral collection of small ovoid cells, previously not described, were located in the anterior preoptic nucleus (APN) of Loo ('31) and extended rostrally and ventrally into the preoptic periventricular gray. The next constituent occupied the paraventricular nucleus (PVN), and was composed of two classes of cells: (1) a small ovoid cell within anterior and medial parvocellular PVN in contiguity rostrally with a similar cell in APN and (2) a larger, angular cell within and adjacent to the lateral PVN in contiguity caudally with cells in the zona incerta (ZI). Further caudally, a larger and more pleomorphic collection of TH neurons was localized in the medial ZI, particularly at midtuberal levels. These cells were not scattered, as previously reported, but were differentiated into two clear-cut densities, a larger medial island and a more elongated lateral island. Cells of ZI, both large and small, extended caudally into the dorsal hypothalamic and subparafascicular nuclei and periventricular gray. In contrast to previous descriptions, no cells were seen in the nucleus reuniens. In the intermediate group, the most rostral constituent occupied the preoptic periventricular gray, extended as far as the lamina terminalis, and merged dorsocaudally with cells in APN. While the variably shaped cells of the hypothalamic periventricular gray (PVG) were still present in the retrochiasmatic region, a striking absence of these cells was noted at midtuberal levels between the dorsomedial and arcuate hypothalamic nuclei. At this level, a new group of small-round TH cells, resembling those of the arcuate nucleus, was identified in the dorsomedial hypothalamic nucleus (DMN). At caudal tuberal levels, similar neurons were found in the posterior hypothalamic nucleus (PH). These neurons overflowed medially into the PVG and caudoventrally into the arcuate nucleus. In the ventral group, the most rostral constituent, composed of both small and ovoid cells in the retrochiasmatic area, appeared to represent the rostral commissural portion of the arcuate nucleus (Arc).(ABSTRACT TRUNCATED AT 400 WORDS)

Water soluble vitamins in granulocytes, erythrocytes, and plasma obtained from chronic hemodialysis patients

A granulocyte fraction, composed primarily of polymorphonuclear neutrophils, was harvested from six male and six female chronic hemodialysis patients receiving folate as their sole vitamin supplement. Cells were assayed for water soluble vitamins and levels compared with cells from 12 age- and sex-matched controls. Thiamin, riboflavin, and vitamin B6 and B12 levels were not significantly different from controls. In contrast, pantothenate and biotin were significantly increased while ascorbate and nicotinate were significantly reduced in dialysis patients. Neutrophil folylmonoglutamates were significantly increased in chronic hemodialysis patients, but after conjugase treatment no significant difference was observed. The erythrocytes and plasma from these two groups were also compared. In the erythrocytes of chronic hemodialysis patients, no vitamin deficiencies were observed. Significantly elevated levels of vitamin B12, riboflavin, biotin, and pantothenate were present in the patients, while thiamin, vitamin B6, nicotinate, and ascorbate were not significantly different from controls. In plasma, only ascorbate was significantly decreased in the patient group; biotin, riboflavin, and pantothenate were elevated. No significant difference was observed for vitamins B6, B12, and thiamin.

Olfactory bulb dopamine neurons survive deafferentation-induced loss of tyrosine hydroxylase

Peripheral deafferentation of the rodent olfactory bulb results in loss of dopamine content, tyrosine hydroxylase activity and immunocytochemical staining for tyrosine hydroxylase in juxtaglomerular dopamine neurons. Reinnervation of the bulb by afferent neurons results in the return of all parameters to control levels suggesting that the dopamine neurons did not degenerate but that the expression of tyrosine hydroxylase enzyme was transneuronally regulated in a static population of juxtaglomerular cells. To evaluate this possibility, we determined the activity and immunocytochemical localization of the second enzyme in the dopamine biosynthetic pathway, DOPA decarboxylase. At a time when tyrosine hydroxylase activity was reduced to 25% of control values, DOPA decarboxylase activity in the lesioned bulb was maintained at about 65% of that in the unlesioned bulb. Immunocytochemical staining with antibodies to both enzymes, performed sequentially in the same sections, demonstrated that in the unlesioned bulb tyrosine hydroxylase and DOPA decarboxylase are co-localized in the same population of juxtaglomerular neurons. Similar results were obtained in adjacent sections each stained with one of the two antibodies. In contrast, in the deafferented bulb, about three times as many neurons were stained with DOPA decarboxylase as with tyrosine hydroxylase antibodies. The DOPA decarboxylase activity measurements and immunocytochemistry argue for the continued presence, in the lesioned olfactory bulb, of a population of tyrosine hydroxylase deficient dopamine neurons. The data suggest that olfactory receptor cell innervation transneuronally regulates the expression of tyrosine hydroxylase by mechanisms separate from those controlling the levels of DOPA decarboxylase.

Cutaneous carcinoma in psoriatic patients treated with PUVA

Eight of 216 psoriatic patients treated at The London Hospital with photochemotherapy (PUVA) have developed a total of twenty-five skin carcinomata. The type and site of tumour are discussed with special reference to the importance of PUVA compared with other risk factors. We suggest that a history of previous skin carcinoma, arsenic therapy or radiotherapy are relative contra-indications to PUVA therapy for psoriasis.

Vitamin content of some normal human brain segments

Nicotinates, pantothenates, riboflavin, vitamins B6 and B12' free (acetyl) and total (free and bound) choline, biopterin, thiamin, biotin, methylated and nonmethylated folates in frontal, temporal, precentral, postcentral, and occipital cortex, thalamus, cerebellum, pons, basal ganglia, and substantia nigra were estimated. Nicotinates are significantly more concentrated in basal ganglia and thalamus than pons. Nonmethylated folate content is not significantly varied in brain segments; the pons contains more methylated folate. Riboflavin content is higher in the basal ganglia and temporal cortex than frontal cortex. Biotin is concentrated in pons and basal ganglia. Thiamin concentration is less in the postcentral cortex than the thalamus and substantia nigra. Biopterin is significantly higher in substantia nigra and basal ganglia than the other brain segments. Total choline content is high in substantia nigra, pons, and thalamus; free (acetyl) choline is significantly elevated in basal ganglia. B12 content is less concentrated in the cortex segments. B6 is highly concentrated in the basal ganglia. Pantothenate content is elevated in pons when compared to the various cortex segments and cerebellum.

Chemical modification of ravidomycin and evaluation of biological activities of its derivatives

Several derivatives of the antitumor antibiotic ravidomycin were synthesized and their antitumor and antimicrobial activities and mode of action were evaluated. Deacylation produced a compound with higher biological activity than the parent. Structure-activity relationship of the derivatives is discussed.

Demethoxyrapamycin (AY-24,668), a new antifungal antibiotic

Demethoxyrapamycin is a new antifungal antibiotic which is co-produced with rapamycin by Streptomyces hygroscopicus. It was isolated as a minor component during recovery of rapamycin. Its antifungal and antitumor activity is compared with that of rapamycin.

Variations in number of dopamine neurons and tyrosine hydroxylase activity in hypothalamus of two mouse strains

Mice of the BALB/cJ strain have more neurons and greater tyrosine hydroxylase (TH) activity in the midbrain than mice of the CBA/J strain (Baker, H., T. H. Joh, and D. J. Reis (1980) Proc. Natl. Acad. Sci. U.S.A. 77: 4369-4373). To determine whether the strain differences in dopamine (DA) neuron number and regional TH activity are more generalized, regional TH activity was measured and counts of neurons containing the enzyme were made in the hypothalamus of male mice of the BALB/cJ and CBA/J strains. TH activity was measured in dissections of whole hypothalamus (excluding the preoptic area), the preoptic area containing a rostral extension of the A14 group, the mediobasal hypothalamus containing the A12 group, and the mediodorsal hypothalamus containing neurons of the A13 and A14 groups. Serial sections were taken and the number of DA neurons was established by counting at 50- to 60-microns intervals all cells stained for TH through each area. In conjunction with data obtained biochemically, the average amount of TH per neuron was determined. In all areas, TH activity in CBA/J mice was significantly less (p less than 0.001) than in BALB/cJ mice, ranging from 48% in the mediobasal hypothalamus to 71% in the medial and dorsal hypothalamus. The number of TH-containing neurons was also significantly less in the CBA/J strain (p less than 0.001), ranging from 49% in the preoptic area to 74% in the mediobasal hypothalamus (MBH). With the exception of the MBH, enzyme activity per neuron was similar in both strains. In the MBH, strain differences in TH activity were greater than those for neuron number, resulting in less TH activity per neuron in the CBA/J strain. The results suggest that strain differences in the number of DA neurons are widespread and involve DA systems throughout the brain. Therefore, differences in whole brain TH activity cannot be attributed only to differences in specific regions. Our findings further support the view that the number of neurons of a specific chemical class may be under genetic control.

Transneuronal regulation of tyrosine hydroxylase expression in olfactory bulb of mouse and rat

Peripheral afferent input regulates the expression of dopaminergic properties in a population of local circuit intrinsic neurons of the rodent olfactory bulb. Lesions of the olfactory receptor neurons produced in the mouse by intranasal irrigation with either ZnSO4 or Triton X-100 and in the rat by surgical deafferentation or axotomy are associated with a decrease in the levels of dopamine (DA), the DA metabolite 3,4-dihydroxyphenylacetic acid (DOPAC), the activity of the enzyme tyrosine hydroxylase (TH), bulb weight and an increase in norepinephrine (NE) levels in the olfactory bulb. The anatomical correlates of the biochemical sequelae of deafferentation of olfactory bulb DA neurons were studied using immunohistochemical techniques to localize TH. Within 3 to 4 weeks all lesions produced a dramatic and uniform reduction in TH staining of the juxtaglomerular DA neurons and their processes which was paralleled by a reduction in DA and DOPAC levels and bulb weight. Seven weeks following reversible chemical lesions produced by Triton X-100, DA and DOPAC levels and tissue weight as well as TH staining in the juxtaglomerular neurons returned to control levels. These observations suggested that DA neurons remained present even when not demonstrable with TH antibodies. Additional evidence for the continued presence of the DA neurons was the ability of the olfactory bulbs from both lesioned mouse and rat to synthesize DA from exogenously administered L-3,4-dihydroxyphenylalanine (l-DOPA). These data suggested that the decrease in DA levels and TH staining in the olfactory bulb following lesions of the olfactory receptor neurons were produced by transneuronal mechanisms since there was no direct injury of the bulb. Furthermore, the demonstration that following reinnervation, catecholamine synthetic capacity is restored suggests that the juxtaglomerular dopamine neurons remain in the bulb and that afferent receptor input is required for expression of TH enzyme.

A simple method for determination of plasma and urinary biotin

Measurement of biotin in plasma and urine has been stimulated by recent descriptions of inborn errors of biotin metabolism and by newly recognized causes of biotin deficiency. Biotin determination in physiologic fluids to document these conditions has been hindered by lack of a widely useable assay. This paper presents a method which employs tritium-labelled biotin, avidin, and nitrocellulose filters to measure urinary and plasma biotin in a rapid and simple manner.