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Biomedical subjects

P Henry

Publications and source records attributed to P Henry.

At least 127 records · Page 7Linked to original sources
PubMed1992

[The effect of inhaled salbutamol on pulmonary gas exchange in patients with chronic obstructive bronchopneumopathy].

The aim of this study is to establish whether or not the inhalation of a puff of salbutamol (Ventoline, 100 micrograms) could induce hypoxemia. Twenty-five chronic obstructive pulmonary disease (COPD) patients were investigated. In a first group of 20 patients arterial blood gases and related indices were measured before and 5, 10, 30, 60 and 90 minutes after inhalation of salbutamol. The oxyhemoglobin dissociation curve was traced before and 90 minutes after the drug intake. Except in two subjects in whom salbutamol dramatically improves arterial blood gases, the drug had no effect on the investigated parameters. It is concluded that salbutamol does not affect the blood gases in COPD patients. In this respect the behaviour of COPD patients differs from that of asthmatics in whom salbutamol generally induced hypoxemia.

Administration, Inhalation↗
PubMed1992

Evaluation of threshold doses of drug action in the horse using hematocrit values as an indicator.

This study was designed to explore the use of hematocrit values as possible indicators of the threshold doses of adrenergic drugs in the performance horse. Acepromazine, detomidine, and fluphenazine were tested for their effects on hematocrit values, with the threshold dose for these effects investigated. Hematocrit values were shown to be quite sensitive to the administration of acepromazine with doses as low as 50 micrograms/horse producing detectable depressions in hematocrit values for up to 2 hours. Increasing the dose increased the magnitude of the effect, but did not appear to prolong it, while in contrast, reducing the dose to below 25 micrograms/horse totally eliminated the effect. The alpha-2 agonist detomidine produced a similar depression in hematocrit values, although doses of 10 micrograms/kg or approximately 5 mg/horse, were needed to produce a measurable effect. The anti-psychotic fluphenazine, which is believed to be an illegally administered drug in race horses, had no significant effect on hematocrit values when comparable doses were administered. In addition, the results of monitoring the hematocrit values of six horses for 48 hours suggested that the variations seen may be partially related to circadian factors, with peak values occurring in the afternoon hours.

Acepromazine↗
PubMed1991

Endoneurial proliferation of perineurial cells in leprosy.

In leprous neuropathy the perineurium has very often an abnormal multilayered appearance and is infiltrated by many different types of inflammatory cells. We report here 13 cases characterized by an abnormal endoneurial proliferation of fibroblasts which seems to differentiate in perineurial cells. In several instances there is formation of many intrafascicular microcompartments. Such aspects have been described in various, but infrequent, cases of experimental and human neuropathies. It seems that severe Wallerian degeneration, diffuse endoneurial macrophage infiltration and lesion of the perineurium might lead to such a process.

Cell Division↗
PubMed1991

The metabolism of exogenous L-dopa in the brain: an immunohistochemical study of its conversion to dopamine in non-catecholaminergic cells of the rat brain.

The characterization and localization of non-catecholaminergic cells producing dopamine after L-Dopa load have been investigated in the normal rat brain by a direct immunohistochemical labelling of amines using specific antibodies. The detection of dopamine-containing non-catecholaminergic cells has been achieved in rats given a commonly used mixture of L-Dopa plus peripheral decarboxylase inhibitor, and compared to controls. Results indicate that serotoninergic neurons tend toward a switch of their metabolism into dopamine production after L-Dopa load in a dose-dependent manner. In addition small non-aminergic cells, identified as aromatic amino-acid decarboxylase-containing cells, were observed to produce dopamine after exogenous L-Dopa load. Possible implications of such results concerning the mode of action of L-Dopa in the brain are discussed.

Administration, Oral↗
PubMed1991

Pulsatile glycoprotein hormone secretion in glycoprotein-producing pituitary tumors.

To study patterns of hormone production and secretion in glycoprotein-producing pituitary tumors, 12 patients with such tumors underwent the following studies. Preoperatively, all patients had serum TSH, LH, FSH, and alpha-subunit levels measured every 15 min for 24 h. Hormone pulses were located by cluster analysis, and pulse parameters were compared to those in healthy young men, healthy young women, healthy postmenopausal women, and subjects with primary hypothyroidism. After surgery, immunocytochemistry for the four glycoproteins was performed on all tumors, and Northern blot analysis was performed in six tumors with probes for the four subunits. By immunocytochemistry, 42% of the tumors were positive for TSH beta, 83% for LH beta, 75% for FSH beta, and 92% for alpha-subunit. Preoperative serum hormone levels varied widely between patients and were not well correlated with the intensity of immunocytochemical staining. Northern blot analysis did not appear to be as sensitive as immunocytochemistry for detection of the glycoproteins. All patients had pulsatile glycoprotein secretion, with pulses of normal frequency but varied amplitude. These results suggest that in patients with glycoprotein tumors, hormone pulses may be an integral part of autonomous secretion, or that hypothalamic control is involved in glycoprotein secretion and, perhaps, in the pathogenesis of these tumors.

Adenoma↗
PubMed1991

Pulsatile prolactin secretion in hyperprolactinemia due to presumed pituitary stalk interruption.

PRL, like other anterior pituitary hormones, is normally secreted in a pulsatile fashion. However, it is not known whether such pulses depend on dopamine and/or other hypothalamic factors. This question can be addressed by investigating patients with large pituitary mass lesions, since such patients often have hyperprolactinemia due to disruption of normal hypothalamic input to the pituitary gland. Six such patients (5 with non-PRL-secreting tumors and 1 with a craniopharyngioma) and 11 healthy control subjects had PRL levels measured every 15 min over 24 h. PRL pulses were located by cluster analysis. All patients had PRL pulses of normal frequency, but increased amplitude. Circadian variation in PRL pulse amplitude, present in healthy women, was abolished in tumor patients. These results imply that normal pituitary levels of dopamine do not control the generation of PRL pulses. Instead, PRL pulses may arise from the pituitary gland, with pulse amplitude and circadian rhythm modulation by dopamine and other hypothalamic factors. Alternatively, the mild hyperprolactinemia associated with large hypothalamic-pituitary tumors may represent partial impairment of dopamine secretion, with sufficient pituitary dopamine levels to maintain normal PRL pulse frequency.

Circadian Rhythm↗
PubMed1991

[Atrial electrophysiological study of unexplained cerebrovascular disorders].

The aim of this study was to detect possible atrial electrophysiological abnormalities in patients with unexplained embolic cerebrovascular accidents without overt atrial arrhythmias. This group was compared with normal controls and a group of patients with paroxysmal atrial fibrillation. Sixty-six patients were studied: Group I normal controls (N = 20); Group II patients with CVA (N = 26) and Group III, patients with paroxysmal atrial fibrillation (N = 20). Each group was divided into 2 subgroups according to age (over and under 45 years). The following parameters were taken into consideration: parameters correlated to atrial excitability (effective and functional refractory periods, adaptation of these refractory periods, intraatrial conduction--A1 and A2, S1A1, S2A2 intervals--, index of latent vulnerability); provocative testing by the extrastimulus technique; classical indices of atrioventricular conduction and sinus node function. In subjects over 45 years of age, the effective refractory periods were shorter in Group III (214 +/- 33 ms) and II (214 +/- 32 ms) than in the control Group I (248 +/- 21 ms), p less than 0.01. This difference was not apparent in younger patients. Inadaptation of the refractory periods was demonstrated equally in Groups II and III in all ages whilst the control subjects showed normal adaptation, p less than 0.05. Intraatrial A1 and especially A2 conduction was significantly prolonged in Group III (94.5 +/- 24 ms) and II (87 +/- 14 ms) compared with the control group (69 +/- 8 ms), p less than 0.01, especially in younger subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Tension headache and psychogenic headache].

Psychogenic headache in the French nosology and the Anglo-Saxon concept of tension headache have many points in common but are not quite identical. Tension headache includes headaches in which the psychic element may be associated with muscular, articular or other causes. Subjects with this type of headache feel as though their skull was compressed by a tight helmet and was heavy, or as though the back of their neck and the occipital region were under tension. The condition is chronic and often lasts for long periods. Psychological and psychopathological analysis discloses the genesis of this tension headache which may simply be a response to a more or less repetitive stress or to anxiety and/or depression, but may also be the somatic expression of a neurotic state with a more consistent structure. This analysis leads to a treatment which includes psychotropic drugs, but where the relational component remains fundamental in the management of these patients.

Emotions↗
PubMed1990

Structure of the gene of tum- transplantation antigen P35B: presence of a point mutation in the antigenic allele.

Mutagen treatment of P815 tumour cells produces tum- variants that are rejected by syngeneic mice because they express new transplantation antigens. These 'tum-' antigens elicit a cytolytic T lymphocyte (CTL) response but no detectable antibody response. The DNA of tum- variant P35 was transfected into P815 cell line P1.HTR. Transfectants expressing tum- antigen P35B were identified on the basis of their ability to stimulate anti-P35B CTL. This was repeated with a cosmid library and a cosmid carrying the sequence encoding antigen P35B was recovered from a transfectant expressing the antigen. Gene P35B is 6 kb long and contains 11 exons. The sequence shows no homology with the previously identified tum- gene P91A nor with any gene presently recorded in the data banks. The antigenic allele of gene P35B differs from the normal allele by a point mutation located in exon 5. This mutation, which replaces a Ser by an Asn residue, was shown by site-directed mutagenesis to be responsible for the expression of the antigen. A synthetic decapeptide covering the sequence surrounding the tum- mutation rendered P815 cells sensitive to lysis by anti-P35B CTL. Surprisingly, the homologous peptide corresponding to the normal sequence of the gene had the same effect, indicating that this tum- mutation does not exert its effect by generating the aggretope or the epitope of the antigenic peptide. As observed previously with gene P91A, we found that fragments of gene P35B containing only exons 4 and 5, which were cloned in non-expression vectors, transferred efficiently the expression of the antigen.

Alleles↗
PubMed1990

Immunohistochemistry of endogenous L-DOPA in the rat posterior hypothalamus.

The aim of this work was to study L-DOPA-containing neuronal structures of the rat posterior and dorsal hypothalamus by means of immunohistochemistry using antiserum against glutaraldehyde conjugated L-DOPA. Aspects and distribution of L-DOPA immunoreaction among cells of the supramammillary nucleus and the A11, A13c and A13 cell groups are described and compared to dopamine immunoreactivity, mainly through a double colored labelling procedure employing a color modification of the DAB reaction by metallic ions. Differences between L-DOPA and dopamine stainings within cell groups as the presence of cells with predominant or exclusive L-DOPA coloration are tentatively explained under the light of previous findings using immunohistochemistry of catecholamines synthesizing enzymes and catecholamines histofluorescence.

Animals↗
PubMed1990

Peripheral neuropathies and lymphoma without monoclonal gammopathy: a new classification.

Recent progress in immunopathological studies of peripheral nerve and lymph node fragments together with 16 personal cases and numerous clinicopathological reports have suggested a new classification of peripheral neuropathies (PN) and lymphomas. These are: (1) PN due to local infiltrations by a T-cell lymphoma: (2) acute polyradiculoneuritis due to active demyelination and associated with infiltrates of a T-cell lymphoma in the epineurium, resembling Marek's disease (which is a T-cell lymphoma); (3) B-cell lymphoma proliferation which may be restricted to or predominate in the peripheral nervous system, with a large clinicopathological heterogeneity ranging from localized forms to ascending polyradiculoneuropathies; (4) angiotropic lymphoma, which is a B-cell lymphoma and may present as an acute mononeuropathy; (5) patients with acquired immunodeficiency syndrome due to lymphomatous infiltrates in the endoneurium, of which 2 cases of PN have been reported; (6) PN associated with organomegaly, endocrinopathy, M-component and skin lesions, certain cases being associated with a plasmocytoma and sometimes Castleman's disease but without any monoclonal gammopathy: (7) classic Guillain-Barré syndrome, prone to develop in patients with extraneural lymphoma but without any lymphomatous infiltrates in the peripheral nervous system; (8) certain cases (4 out of 16 in our series) where there is no clear relationship between PN and lymphoma, and there are mainly features of axonal degeneration. Inflammatory perivascular infiltrates were sometimes present in the epineurium.

Aged↗
PubMed1990

Cluster headache: ultrastructural evidence for mast cell degranulation and interaction with nerve fibres in the human temporal artery.

It has been suggested that histamine plays an important role in the pathogenesis of cluster headache. In addition, both neurogenic and vascular components have been described during cluster headache attacks without an obvious anatomical link between them. Our ultrastructural observations of human temporal arteries from cluster headache patients and their comparison to those from a control group strongly suggest that mast cells may be this link. Mast cells in both groups show a very close apposition with nerve fibres, suggesting a functional interaction between them. Moreover, in the cluster headache group exclusively, adventitial mast cells show profound morphological modifications suggesting progressive degranulation. These data strongly suggest that mast cells could be directly or indirectly involved in the pathophysiology of cluster headaches.

Adult↗
PubMed1990

Pathophysiology of pulsatile and copulsatile release of thyroid-stimulating hormone, luteinizing hormone, follicle-stimulating hormone, and alpha-subunit.

Under physiological conditions, TSH, LH, FSH, and alpha-subunit are released in discrete pulses. To further characterize their neuroregulation and to investigate possible copulsatile secretion of these glycoprotein hormones, we studied the 24-h pulse profiles of all four hormones in each of four subject groups: young men, young women, postmenopausal women, and subjects with untreated primary hypothyroidism. Gonadotropin pulse properties in euthyroid men and women were similar to those previously reported, and hypothyroid subjects had normal gonadotropin pulse patterns. TSH release was pulsatile in all groups; hypothyroid subjects had increased pulse amplitude, but loss of the usual nocturnal increases in pulse amplitude. alpha-Subunit concentrations were pulsatile in all groups, with minimal circadian variation; postmenopausal and hypothyroid subjects had increased alpha-subunit pulse amplitude. We then tested pulse concordance among the four simultaneous hormone series. alpha-Subunit and the gonadotropins were significantly coreleased (triple coincidence), suggesting that all three hormones are closely linked to processes that regulate GnRH secretion. alpha-Subunit bursts were also significantly coincident with those of TSH in men, postmenopausal women, and hypothyroid subjects. Interestingly, TSH pulses were significantly concordant with those of LH and FSH, and all four hormones were significantly concordant in men, postmenopausal women, and hypothyroid subjects. In conclusion, the present findings imply that an underlying unified signal coordinates pulsatile hormone secretion from both gonadotrophs and thyrotrophs.

Adult↗
PubMed1990

Relationship between scores on developing cognitive abilities test and scores on medical college admissions test for nontraditional premedical students.

The relationship of students' performance on the Developing Cognitive Abilities Test (DCAT), a test of scholastic aptitude, and their subsequent performance on the Medical College Admission Test (MCAT) were examined for 122 nontraditional premedical students who participated in a medical educational preparatory program. A stepwise multiple regression analysis produced moderate, though significant multiple correlations among subscores on the two tests. While there were a few exceptions, for the most part all of the subscores on the Developing Cognitive Abilities Test made a significant contribution to the regression equation in the prediction of scores on MCAT subtests. Implications for the value of the Developing Cognitive Abilities Test as an admissions tool as well as providing direction for possible intervention are discussed.

Aptitude Tests↗