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Biomedical subjects

M Henry

Publications and source records attributed to M Henry.

At least 217 records · Page 12Linked to original sources
PubMed1987

Neurotrophic effect of naturally occurring long-chain fatty alcohols on cultured CNS neurons.

A long-chain fatty alcohol,n-hexacosanol, that we have isolated from the Far-Eastern traditional medicinal plant, Hygrophila erecta, Hochr., is shown to promote the maturation of central neurons. Added at 500 nM to fetal rat brain neurons in culture, it increased both neurite outgrowth by a factor of 4-6 and the number of collaterals, especially in multipolar neurons. The biochemical differentiation of cultured neurons was also strikingly enhanced by this compound: it increased the protein content and almost doubled the activities of two neuron-specific enzymes, phosphate-activated glutaminase and neuron-specific enolase, by 92 and 78%, respectively. Extensive studies with several synthetic long-chain fatty alcohols showed that the neurotrophic activity was maximal for n-hexacosanol. It is suggested that some long-chain fatty alcohols with an appropriate length of hydrocarbon chain might play an important role in central neuron development.

Animals↗
PubMed1987

Role of exposure parameters in toxicity of aerosolized diesel fuel in the rat.

Sprague-Dawley rats were exposed to aerosolized diesel fuel (ADF) to determine the potential health effects in military troops during exposure to this visual obscurrant. Acute range finding studies were performed to estimate exposure conditions at which minimal (less than 1%) mortality would occur. This information was used in the design of a repeated exposure study to test the relative significance of the frequency of exposures, the duration of exposure, and aerosol concentration in any toxicity which might occur. Animals were exposed once or three times per week for a total of nine times to concentrations ranging from 1.3 mg ADFl-1 to 6 mg ADFl-1 and exposure durations of 2 or 6 h. Body weight and food consumption were recorded at weekly intervals during the exposure period and in animals that were retained for 2 weeks after the last exposure. Animals were used for a variety of endpoints, including neurotoxicological tests, pulmonary function tests, hematology, clinical chemistry, organ weights, and histopathology, either within 2 days of the last exposure or after the 2-week recovery period. Animals exposed to ADF showed an initial depression in body weight followed by a slower rate of growth than the sham exposed controls. No exposure related changes were observed in any of the neurotoxicology assays. The lung was the primary site of toxicity. Focal accumulations of pulmonary free cells were observed histologically, with thickening and hypercellularity of nearby alveolar walls. The number of lavaged pulmonary free cells increased similarly. Both pulmonary wet and dry weights increased. Lung volumes were altered by exposure, including increased FRC and decreased TLC. Carbon monoxide diffusing capacity was decreased. Histologic abnormalities were not observed in any other organs. Of the exposure parameters tested, the frequency of exposure appeared to be the most significant in relation to degree of toxicity.

Aerosols↗
PubMed1987

Sequential antilymphoblast globulin and cyclosporine for renal transplantation.

The nephrotoxic effects of cyclosporine (CsA) seem to be augmented by co-existing renal injury. A high rate of prolonged delayed function (acute tubular necrosis [ATN]) and non-function (NF) has been associated with the use of CsA prior to and following renal transplantation. Cyclosporine has also been associated with a slower recovery of allograft function and poor baseline renal function even in allografts that function immediately compared with conventionally treated recipients. In 1983 we hypothesized that the rate of ATN and NF following renal transplantation could be decreased and more normal kidney function achieved if renal injury was resolved before adding the nephrotoxic effects of CsA. A group of 300 nonsplenectomized, uremic recipients have received 304 renal transplants and have been initially immunosuppressed with azathioprine, prednisone, and Minnesota antilymphoblast globulin (ALG) prior to starting maintenance CsA and prednisone. The incidence of NF has been 1.9% and the development of ATN has been 7.6% following transplantation with sequential use of ALG and CsA. Other benefits to the renal recipient have also occurred with use of this immunotherapy protocol. Renal allograft survival for recipients of first, second, and third renal allografts has been higher than that generally reported with cyclosporine and prednisone alone. Rejection episodes have been infrequent during the first six months posttransplant, as 75% and 62% of first and second renal allograft recipients have remained rejection-free. Clinically significant infectious complications were infrequent. No cadaver recipient has developed a lymphoma. Moreover, the initial hospitalization following transplantation with sequential ALG/CsA has been short and generally uncomplicated. We conclude that sequential ALG/CsA following renal transplantation provides excellent early posttransplant immunosuppression while avoiding the nephrotoxic effects of CsA and also provides the steroid and infection-sparing benefits derived from maintenance CsA therapy.

Acute Kidney Injury↗
PubMed1987

Glomerular epithelial cell lesions in rat renal isografts.

Visceral glomerular epithelial cell lesions--microvillus formation, loss of foot processes, osmiophilic inclusion droplets, balloon-like malformation of cell processes, degeneration, necrosis, and loss of cell processes from capillary basement membranes--are found in rat renal isografts 1 mth after transplantation. The lesions, which are most readily recognized in perfusion-fixed material, are essentially focal, affecting neither all glomeruli, nor all cells in any glomerulus, bear no relation to the degree of interstitial nephritis in the graft, and are associated with albuminuria and with focal capillary sclerosis in some glomeruli. They are not restricted to renal isografts but are found in aging rats, in different experimental models of glomerular disease and in clinical glomerular disorders, again in association with proteinuria and glomerulosclerosis. It is therefore proposed that glomerular epithelial cell damage increases capillary permeability and impairs maintenance of the integrity of the capillary wall, leading to proteinuria and focal glomerulosclerosis.

Animals↗
PubMed1987

Experimental folic acid nephropathy.

In rats, single intravenous doses of folic acid induce damage to renal tubular epithelium, deposition of folic acid in tubular lumens, increase in wet kidney weight, oliguria and interstitial connective tissue proliferation. Separation of the nephrotoxic and obstructive effects of folic acid was attempted by pretreatment with NH4Cl or NaHCO3. These effects of folic acid were unaltered by pretreatment with NH4Cl and there was, in addition, accumulation of eosinophilic droplets in papillary collecting duct epithelium. After pretreatment with NaHCO3, folic acid deposition is decreased or absent; there is a smaller increase in wet kidney weight; the rats are polyuric rather than oliguric; interstitial connective tissue proliferation is reduced; and no droplets form in papillary collecting ducts, but lesions are still present in proximal convoluted tubule epithelial cells. These findings indicate that folic acid has direct nephrotoxic effects independent of intraluminal folic acid deposition, and that damage to renal epithelium, unlike that induced by many nephrotoxins, occurs at several levels of the nephron.

Ammonium Chloride↗
PubMed1987

Clinical and endocrine aspects of the oestrous cycle in donkeys (Equus asinus).

Oestrous behaviour and occurrence of ovulation was studied in 13 jenny asses (3-18 years) during a 15-month period. Teasing was performed daily and follicular growth, ovulation and changes of the genitalia were checked every other day by rectal palpation during dioestrus or the anovulatory season or daily during oestrus and when a follicle greater than or equal to 3 cm in diameter was present. Plasma oestrogens and progesterone levels were measured by radioimmunoassay (RIA). Of the 13 jennies, 6 showed a typical seasonal ovarian activity, 1 stopped cycling only at the end of the experiment, 2 ovulated regularly and 4 did not cycle. Mean (+/- s.d.) length of the anovulatory season in the 6 jennies with seasonal cyclic ovarian activity was 166.3 +/- 63.2 days (74-263 days). Irregular oestrous periods were detected during the anovulatory season of these jennies. Irregular signs of oestrus and follicular growth were detected in the 4 jennies which remained acyclic during the whole experiment. Mean (+/- s.d.) length of the ovulatory season was 197.8 +/- 63.4 days (102-291 days). Overall mean +/- s.d. lengths for the oestrous cycle and dioestrous and oestrous periods were 25.9 +/- 2.7 (n = 74), 18.2 +/- 2.3 (n = 70) and 7.9 +/- 2.5 (n = 79) days. Ovulatory oestrous periods tended to be longer at the start and end of the season than during the summer months. Dioestrous length was not affected by season.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

[Epidemiology of malaria and the antimalarial campaign in Mayotte (Comoro archipelago, Indian Ocean). Development of the situation between 1976 and 1986. Outlook].

Up to 1976 an integrated malaria control programme has been carried out in Mayotte island. By 1980, there was a drastic reduction of the number of the malaria cases and of the plasmodic index (below 1%). But in 1984, an uprise of cases and a consistent increase of the plasmodic index was observed throughout the island (up to 10%). It is supposed to be due to the laxity in malaria control measures. Immediately a reinforcement of all aspects of malaria control measures was undertaken. Every house is sprayed four times a year with fenitrothion (2 g/m2). Chemical and biological ("guppy" fishes) larviciding measures were extensively applied throughout the island together with simple environmental measures like filling peridomestic breeding sites. Mass chemoprophylaxis was gradually decreased and is now only applied for pregnant women according to the W.H.O. recommendations. Presumptive treatment of febrile cases is generalized before laboratory confirmation. The surveillance of malaria prevalence is a continuous process both active and passive but, every year, a randomized parasitical and serological survey is carried out in a sample of representative villages. In 1986 there was only 3 indigenous cases observed despite the introduction of numerous carriers from neighbouring infected countries. It appears that pertinent control can reduced or may be eliminate malaria transmission in a short period of time. But the maintenance of the malaria clearance in the local, ecological and geographical context need a continuation of the control measures at least for the near future, as the population has lost most of its immunity and has become highly vulnerable to malaria.

Humans↗
PubMed1986

Visualization of replicating herpes simplex virus in cervical dorsal root ganglia of mice following explant of individual ganglion onto susceptible indicator cells.

Herpes simplex virus (HSV) establishes a latent state in the sensory ganglia of the peripheral nervous system of its natural or experimental host following primary infection. At various times thereafter, the virus can be reactivated from the latent state whereby it migrates back to the periphery and sometimes initiates a clinical syndrome referred to as recurrent disease. We inoculated mice in the right ear pinna and, following recovery from primary infection, killed the mice at various intervals following either the presence or absence of peripheral stimulations. Explanted cervical dorsal root ganglia yielded HSV in culture and was positive for HSV-like virus particles when viewed with the electron microscope. Hematoxylin and eosin staining showed neuron degeneration, and corresponding HSV-specific immunoperoxidase stains were also positive. The data indicate that ganglionic cells are capable of supporting replicating HSV and that, in vitro, numerous ganglionic cells can be infected simultaneously.

Animals↗
PubMed1986

Role of cytosolic calcium in the control of cAMP content by calcium in bovine parathyroid cells.

In the present studies we used the calcium (Ca2+)-sensitive dye Quin-2 to determine whether the cytosolic (Cyt) Ca2+ mediates the effects of extracellular (EC) Ca2+ on cAMP accumulation through changes in adenylate cyclase and phosphodiesterase activity in bovine parathyroid cells (bPTC). In dispersed (d) bPTC, increasing the EC Ca2+ from 0.5 to 2 mM produces a rise in the Cyt Ca2+ from 179 to 646 nM which is associated with a 52% inhibition of agonist-stimulated cAMP accumulation. Over this range of free Ca2+ adenylate cyclase activity decreased by approx. half (57%) and phosphodiesterase activity increases 2-fold (101%) suggesting that changes in the Cyt Ca2+ can account for the effects of EC Ca2+ on cAMP through changes in these enzymes. Unlike dbPTC, 4-day-old cultured bPTC show only a 23% suppression of cAMP by high EC Ca2+ and a reduced rise in the Cyt Ca2+ from 0.5 to 3 mM EC Ca2+. Although there is no reduction in the Ca2+ sensitivity of adenylate cyclase, phosphodiesterase activity shows no change at varied free Ca2+. Thus, this diminished Ca2+ sensitivity of phosphodiesterase activity, and the decreased rise in Cyt Ca2+ relative to EC Ca2+ may both contribute to the resistance to the effects of EC Ca2+ on cAMP content in cultured cells. Because in addition to Cyt Ca2+, protein kinase C may also mediate the effects of EC Ca2+ on PTH release, we studied the effects of TPA (12-alpha-tetradecanoylphorbol 13-acetate) on agonist-stimulated cAMP in dbPTC.(ABSTRACT TRUNCATED AT 250 WORDS)

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1986

Glomerular damage after kidney preservation.

Severe proteinuria occurs during isolated organ perfusion of kidneys removed from SD and DA rats and subjected to 24-hr cold preservation. In both strains increased glomerular permeability was associated with changes in glomerular visceral epithelial cells, particularly cytoplasmic edema and detachment of cells from capillary basement membranes. Foot processes were intact and staining for sialoglycoprotein was retained. The changes were compatible with survival of the isograft kidney after transplantation, but moderate proteinuria was found in some rats after one month. Protein loss in the urine during isolated organ perfusion is very much less in kidneys subjected to 4-hr cold preservation, and the glomerular epithelial cells are normal or show only minimal cytoplasmic edema on electron microscopy. The experiment shows that significant damage to glomeruli may occur during preservation prior to transplantation, and the model itself can be usefully exploited to determine the relation between increased glomerular permeability to albumin and the associated changes in the glomerular capillary wall.

Animals↗
PubMed1986

Diabetic foot infections. Bacteriologic analysis.

Diabetic patients with foot infections were prospectively evaluated over a two-year period. Cultures from reliable specimens avoiding contamination with foot ulcers were obtained in 54 infectious episodes. Staphylococcus species, Enterococcus species, Corynebacterium species, and various species of Enterobacteriaceae were commonly isolated. Common anaerobic isolates included Peptostreptococcus magnus, Peptostreptococcus prevotii, and Bacteroides species. Results of cultures from 94 unreliable specimens were similar. Results of reliable and unreliable specimens obtained simultaneously in 26 patients agreed in seven (27%), but antibiotics selected for organisms isolated from unreliable specimens would have adequately covered pathogens found in the reliable culture in 24 (93%). Diabetic foot infections usually involve mixed bacterial flora, including aerobic, facultatively anaerobic, and anaerobic microorganisms. Specimens should be obtained from infected tissue that does not communicate directly with the foot ulcer if possible. If such specimens are not available, cultures of purulent exudate within the foot ulcer or soft-tissue sinuses may provide useful information on which to base decisions about antibiotic therapy. Broad-spectrum beta-lactam antibiotics or a combination of antibiotics active against facultatively anaerobic cocci and bacilli as well as anaerobes provide the best empirical antimicrobial coverage in these patients.

Abscess↗
PubMed1985

Cardiogenic shock associated with calcium-channel and beta blockers: reversal with intravenous calcium chloride.

Two cases in which oral ingestion of beta blocker and slow calcium-channel blocker was associated with profound hypotension and bradycardia are reported, including one case in which serum levels of both drugs were documented in the normal range at a time of severe clinical toxicity. Though unresponsive to usual therapeutic interventions, both patients showed an immediate and dramatic response to intravenous calcium chloride. It is recommended that intravenous calcium chloride be considered in any patient using routine doses of these two agents who presents with hypotension and/or bradycardia.

Adrenergic beta-Antagonists↗
PubMed1985

Regulation of parathyroid hormone release and cytosolic calcium by extracellular calcium in dispersed and cultured bovine and pathological human parathyroid cells.

Alterations in parathyroid glandular sensitivity to calcium may contribute to the hypersecretion of PTH in hyperparathyroidism. Since the cytosolic calcium concentration may mediate the effects of extracellular calcium on PTH release, we have employed the calcium-sensitive intracellular dye QUIN-2 to examine the relationship between extracellular calcium, cytosolic calcium, and PTH secretion in adult, neonatal, and cultured bovine as well as pathological human parathyroid cells. PTH release was measured using C- and N-terminal radioimmunoassays. Neonatal bovine parathyroid cells showed a greater set-point for secretion (the Ca++ concentration causing half of the maximal inhibition of PTH release) than adult cells (1.27 +/- 0.11 vs. 1.06 +/- 0.11 mM extracellular calcium, P less than 0.01), and a slightly higher extracellular calcium was necessary to raise the cytosolic calcium concentration to a given level in neonatal than in adult bovine parathyroid cells. In individual neonatal and adult cell preparations, there was a close correlation between the set-point for secretion and the "set-point" for cytosolic calcium (r = 0.832, P less than 0.001). In cells from five human parathyroid adenomas, which had an increase in set-point for secretion, the extracellular calcium concentration necessary to raise the cytosolic calcium concentration to a given level was slightly greater than in the neonatal cells. In four preparations of human parathyroid cells there was a significant correlation between the set-points for secretion and cytosolic calcium (r = 0.856, P less than 0.01). Because neonatal bovine and pathological human parathyroid glands show cellular hyperplasia, we studied the temporal relationship between cellular proliferation and the regulation of PTH release and cytosolic calcium concentration in cultured bovine parathyroid cells. Cellular proliferation, estimated by 3H-thymidine incorporation, increased significantly in culture from 104 +/- 10.1 counts/well on day 1 (first 24 h in culture) to 588 +/- 188 and 6,156 +/- 649 counts/well on days 2 and 4, respectively. In cultured cells on day 1, highly Ca++ (2-3 mM) inhibited maximal PTH release by 58.8 +/- 3.2%, which decreased significantly (P less than 0.001) to 38.2 +/- 1.9 and 17.1 +/- 3.7% on days 2 and 4, respectively. The cytosolic calcium observed at 3 mM calcium on day 1 was 701 +/- 43 nM, which declined to 466 +/- 60 and 314 +/- 14 nM on days 2 and 4 (P less than 0.05). There was a close correlation between this progressive decrease in maximal inhibition of PTH release and the cytosolic calcium at high extracellular calcium in cultured cells (r = 0.99, P < 0.001). Thus, during active proliferation of cultured cells, there is an alteration in the regulation of cytosolic calcium at a given extracellular calcium concentration, and changes in the regulation of PTH release and cytosolic calcium by extracellular calcium may be related to enhanced cellular proliferation.

Animals↗