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C J de Groot

Publications and source records attributed to C J de Groot.

At least 73 records · Page 4Linked to original sources
PubMed1987

Reciprocal regulation of glutamine synthetase and carbamoylphosphate synthetase levels in rat liver.

In glucocorticosteroid-treated diabetic rats, glutamine synthetase enzyme levels in the liver are decreased 3-fold, whereas carbamoylphosphate synthetase enzyme levels are increased 2.3-fold. In addition, immunohistochemistry shows that under these conditions the distribution of carbamoylphosphate synthetase is expanded over the entire liver acinus, whereas that of glutamine synthetase is reduced to very few cells bordering the central (terminal hepatic) veins. Using a newly isolated cDNA complementary to rat liver glutamine synthetase mRNA, we show that this regulation is primarily effected at a pretranslational level. (For data on carbamoylphosphate synthetase mRNA levels, see De Groot et al. (1986) Biochim. Biophys. Acta 866, 61-67). Furthermore, hybridization studies show stimulatory effects of both glucocorticosteroids and thyroid hormone on the glutamine synthetase mRNA level. Attempts to localize glutamine synthetase mRNA within the liver acinus by selective destruction of the pericentral zone failed because of generally low levels of liver mRNAs after CCl4 poisoning. In contrast to the situation after birth, significantly higher glutamine synthetase mRNA/enzyme activity ratios in fetal rat liver point to the presence of additional post-transcriptional control mechanisms before birth. These findings complement similar observations on carbamoylphosphate synthetase gene expression (De Groot et al. (1986) Biochim. Biophys. Acta 866, 61-67).

Animals↗
PubMed1987

Cerebrospinal fluid cells in multiple sclerosis and other neurological diseases: an immunocytochemical study.

Determinations of mononuclear cell subsets in cerebrospinal fluid (CSF), using monoclonal antibodies against surface antigens which identified pan T-cells, helper/inducer T-cells, cytotoxic/suppressor T-cells and Ia-positive cells, were performed in patients with multiple sclerosis (MS), other neuroimmunological diseases (NID), infectious diseases (INF) of the central nervous system and with other neurological diseases. Whereas there was an elevated helper T/suppressor T ratio in CSF of patients with NID (Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, cerebral vasculitis), no other significant differences could be detected between the different groups of patients. Our results suggest that analysis of these mononuclear cell subsets in CSF is not helpful in discriminating between MS and other neurological diseases and that in MS patients changes in disease activity are not clearly indicated by fluctuations in the different CSF cell subsets. Further studies will be needed to confirm our findings in NID patients and to understand the diagnostic and theoretical implications.

Cell Count↗
PubMed1987

The time of separation of the umbilical cord.

The time of separation of the umbilical cord was studied in 911 neonates. The mean time of separation was 7.4 days (SD 3.3, range 1-29 days). We sought a possible relationship between the time of cord separation and various factors in the perinatal period. Cord separation was delayed when antibiotics needed to be administered to the neonate because of sepsis, when the infant was born prematurely, delivered by Caesarean section or had a low birth weight. The cord separated slightly earlier in female than in male infants. None of the infants studied suffered from omphalitis and it would appear that "delayed" separation of the cord is not always necessarily accompanied by severe leucocyte dysfunction.

Bacterial Infections↗
PubMed1987

Macrophages in the central nervous system of the rat.

In an immunohistochemical study using monoclonal antibodies, which exclusively recognize cells of the monocyte-macrophage lineage, and monoclonal antibodies against the Ia-antigen, we describe the occurrence of macrophages in the developing and adult central nervous system (CNS). In normal adult brain, no macrophages could be detected in the CNS parenchyma; only in the meninges and the choroid plexes were a few macrophages found. During ontogeny, numerous phagocytic cells infiltrated the CNS parenchyma; these cells which did not express Ia are blood-borne. About three weeks after birth, all macrophages had disappeared from the CNS. As microglia in adult and developing brain do not stain with the anti-macrophage antibodies, we suggest that microglial cells are not related to the mononuclear phagocyte system and do not have a hematogenous origin.

Animals↗
PubMed1987

Presence of Ia-positive cells in the central nervous system of the rat during various pathological conditions.

The rat central nervous system (CNS) was analyzed immunohistochemically during various pathological conditions by using monoclonal antibodies specific for rat T lymphocytes, rat macrophages and Ia antigen. It was found that in immunologically mediated disease infiltrating macrophages do express the Ia antigen, whereas in nonimmunologically mediated disease they do not. The results suggest that based on the composition of the mononuclear phagocyte infiltrate a clear distinction can be made between different inflammatory reaction types within the CNS.

Animals↗
PubMed1986

Developmental and hormonal regulation of carbamoyl-phosphate synthase gene expression in rat liver: evidence for control mechanisms at different levels in the perinatal period.

Carbamoyl-phosphate synthase gene expression is found to be primarily regulated by conditions that enhance hepatic glucocorticosteroid levels (hormone injections) and cyclic AMP levels (induction of diabetes). After birth, changes in the level of carbamoyl-phosphate synthase protein follow changes in the level of carbamoylphosphate synthase mRNA, suggesting a pretranslational control mechanism. In fetal rats, carbamoyl-phosphate synthase gene expression is regulated by the same factors as in adults. However, both the level to which carbamoyl-phosphate synthase mRNA can accumulate and the extent to which mRNA can be translated appear to be limited, indicating control mechanisms at the pretranslational and translational level. Finally, in the immediate postnatal period, a transient but pronounced decrease in the rate of degradation of carbamoyl-phosphate synthase protein may play a role in the accumulation of the enzyme.

Adrenalectomy↗
PubMed1986

[Chronic benign neutropenia possibly caused by a plasma factor].

In this article two patients are reported with recurrent upper airways and ENT-infections. Laboratory investigation showed a persistent neutropenia. The bone marrow aspirations showed a normal cellularity of the erythroid series and the megakaryocytes. The myeloid series were normal with a decreased number of mature segmented neutrophils. In these patients the serum levels of immunoglobulins were within normal range and antibodies against the white cells could not be demonstrated. By the age of 2-3 years the recurrence of infections had decreased and infections of importance have not been reported since. By that age the peripheral white count was not abnormal. This combination of signs and symptoms is known as 'chronic benign neutropenia'. The etiology is obscure. Our investigation in one case (by that time recovered) showed a diminished growth of the myeloid series of donor bone marrow in the presence of patient's serum. This suggests a plasma-factor responsible for the maturation of the myeloid series. This finding has not yet been reported in the literature.

Agranulocytosis↗
PubMed1984

Regulation of mRNA levels of rat liver carbamoylphosphate synthetase by glucocorticosteroids and cyclic AMP as estimated with a specific cDNA.

The construction and cloning of a cDNA complementary to the mRNA of rat liver carbamoylphosphate synthetase (ammonia) is described. Using this cDNA, the size of the mature, cytosolic carbamoylphosphate synthetase (ammonia) mRNA is estimated to be 6.0 Kb. The levels of carbamoylphosphate synthetase (ammonia) mRNA in liver are shown to be regulated by glucocorticosteroids and cyclic AMP. By studying mRNA levels of carbamoylphosphate synthetase, albumin and phosphoenolpyruvate carboxykinase, using specific cDNA clones, we show that carbamoylphosphate synthetase gene expression, like that of albumin is liver-specific.

Animals↗
PubMed1984

Case report. Intra-uterine demonstration of bowel duplication by ultrasound.

In this case report a patient is presented, showing large sonolucent areas inside the fetal abdomen at 20 wk of gestation. Gastrointestinal (GI) tract obstruction was suspected. There was no polyhydramnios. After premature delivery the child showed marked abdominal distention, but stayed in good condition without signs of GI tract obstruction. At laparotomy, a 30 cm long, distended duplication of the terminal ileum was removed. Postoperative course was uneventful.

Adult↗
PubMed1983

Congenital nemaline myopathy: two patients with consanguineous parents, one with a progressive course.

Clinical, morphological and genetic data are presented on two unrelated children with congenital nemaline myopathy. In one of these, the weakness and hypotonia were progressive. The parents of both children were second cousins. These cases together with those already published suggest that the frequency of consanguineous marriages in parents of children with nemaline myopathy is increased. This is a further argument in favour of an autosomal recessive type of congenital nemaline myopathy in addition to the autosomal dominant variety.

Biopsy↗
PubMed1979

Infantile neuroaxonal dystrophy and giant axonal neuropathy: are they related?

Light and electron microscopic findings from two sural nerve biopsies obtained at a one-year interval from a patient with the clinical features of Seitelberger's disease are described. Ballooned axons with accumulations of membranous profiles, vesicles, mitochondria, and a homogeneous center were present, and there were masses of 90 A filaments in endothelial, endoneurial, perineurial, and Schwann cells. These pathological alterations were less prominent in the second nerve biopsy, which showed a more pronounced decrease in myelinated fibers. The case shows that a generalized increase of 90 A filaments in structures of the peripheral nervous system is not a phenomenon exclusively occurring in patients with giant axonal neuropathy and, furthermore, that it may be a transitory feature.

Axons↗