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Biomedical subjects

H Lambert

Publications and source records attributed to H Lambert.

At least 19 recordsLinked to original sources
PubMed1992

Human HSP27 is phosphorylated at serines 78 and 82 by heat shock and mitogen-activated kinases that recognize the same amino acid motif as S6 kinase II.

The intracellular concentration of the 27-kDa mammalian heat shock protein, HSP27, increases several-fold after heat and other metabolic stresses and is closely associated with the acquisition of thermotolerance. Posttranslational modifications may also affect the function of HSP27. Heat shock of HeLa cell cultures, or treatment with arsenite, phorbol ester, or tumor necrosis factor, caused a rapid phosphorylation of preexisting HSP27 and the appearance of three phosphorylated isoforms, HSP27 B, C, and D. Digestion with trypsin and fractionation of the peptides by reverse phase high performance liquid chromatography revealed three 32P-labeled phosphopeptides. Microsequence analysis identified peak I as Ala76-Leu77-Ser78-Arg79 and peak II as Gln80-Leu81-Ser82-Ser83-Gly84-Val85- Ser86-Glu87-Ile88-Arg89; peak III contained the undigested peptide pair Ala76-Arg89. Ser82 was the major site and Ser78 the minor site of phosphorylation. Mutant proteins with Ser78 or Ser82 altered to glycine or Ser78-Ser82 double mutants were phosphorylated to reduced extents in vivo after heat or arsenite treatment. Ser78 and Ser82 (and Ser15) occur in the sequence motif RXXS, which is recognized by ribosomal protein S6 kinase II. Mitogenic stimulation of serum-deprived, Go-arrested Chinese hamster cells with serum, thrombin, or fibroblast growth factor also stimulated phosphorylation of HSP27 Ser78 and Ser82, and mitogenic stimulation and heat shock activated protein kinase activities that phosphorylated HSP27 and protein S6 in vitro. These results suggest that HSP27 may exert phosphorylation-activated functions linked with growth signaling pathways in unstressed cells. A homeostatic function at this level could protect cells from adverse effects of signal transduction systems which may be activated inappropriately during stress.

Amino Acid Sequence↗
PubMed1992

Transient non-cardiogenic pulmonary edema following massive ingestion of ethylene glycol butyl ether.

A case of acute poisoning with ethylene glycol butyl ether (EGBE) is reported in a chronic alcohol abuser. On admission the 53-year-old patient was comatose with metabolic acidosis, shock, and noncardiogenic pulmonary edema confirmed by haemodynamic study. Following supportive treatment and haemodialysis the outcome was favorable. The relationship between respiratory failure and EGBE is examined.

Alcoholism↗
PubMed1992

The cultural logic of Indian medicine: prognosis and etiology in Rajasthani popular therapeutics.

This paper considers certain ways of describing and treating sickness in rural Rajasthan, and the representations of sickness and of the body on which they are based. Two indigenous medical or 'ethnomedical' perspectives on illness and its treatment emerge from the analysis of ethnographic material collected during field research in northern India. In the first part of the paper various characterizations of South Asian medicine are discussed, and I suggest that Western preconceptions about the nature and purpose of 'medicine' itself has led one of these perspectives to be highlighted in anthropological considerations at the expense of the other. A further dimension of ethnomedicine emerges through discussions of local therapeutic rituals and discourses about sickness and the body. This consideration of one domain of local therapeutics reveals its underlying cultural logic and highlights ethnomedical formulations that have heretofore been analytically neglected. It does not address the formal or textually based Indian medical traditions to any extent. It is concerned with the cultural construction of sickness and medicine among Hindu lay people and folk healers and employs folkloric material that, though rarely considered in anthropological writings on South Asia, may be fruitful guide to the meanings which sickness has for those experiencing and treating it.

Culture↗
PubMed1992

Enhanced gamete interaction in the sperm penetration assay after coincubation with pentoxifylline and human follicular fluid.

OBJECTIVE: To evaluate the effect of pentoxifylline and heat-inactivated human follicular fluid (FF) on performance in the sperm penetration assay (SPA) as a paradigm for the effect of these agents on human sperm-egg interaction in vivo and in vitro fertilization. DESIGN: Semen specimens from men undergoing SPA testing for evaluation of suspected male factor infertility were coincubated with neat medium or media supplemented with pentoxifylline or human FF in a nonblinded manner. PARTICIPANTS: Twenty male factor infertility patients. INTERVENTIONS: Semen specimens were preincubated with: [1] pentoxifylline 0.25 mg/mL; [2] 10% human FF; [3] pentoxifylline+human FF; and [4] neat Biggers, Whitten, and Whittingham medium. MAIN OUTCOME MEASURES: Differences in the rate of penetration of zona-free hamster oocytes. RESULTS: Preincubation with either human FF or pentoxifylline produced a significant improvement in hamster egg penetration rates. Coincubation with a combination of human FF and pentoxifylline resulted in a significant enhancement of penetration as compared with single agent treatment. CONCLUSIONS: Coincubation of sperm with human FF and pentoxifylline may provide a means of enhancing sperm activity for insemination and assisted reproduction.

Animals↗
PubMed1992

[Current treatment of poisoning by ingestion of caustic substances].

Lesions by ingestion of corrosive substances had so far been treated at the time of sequelae. In the seventies several events modified deeply the epidemiology and the early care of these poisonings. At that time household products like highly concentrated basic and acid substances and oxidizing agents were distributed and led to an increase of the number and the severity of these intoxications. In the same time, fiberoptic endoscopy of the digestive tract played a leading part to evaluate the diagnosis and the prognosis of these poisonings at an early stage, and thus, with accurate intensive care and digestive surgery contributed to generate appropriate guidelines, according to the severity. The first step of the treatment is fasting, fluid replacement and analgesic if required. A full examination must be performed, especially in the throat even if there is no strong correlation between early clinical signs and the severity of the lesions; blood samples must be obtained to look for metabolic acidosis, hyperleukocytosis hemolysis and consumption coagulopathy which could be better indicators of the severity. Fiberoptic endoscopy of the upper digestive tract should be performed as soon as the physical and psychological patient's condition is stable; if possible before the twelfth hour and no more late than the twenty-fourth hour. It should determine the lesions: type, range and grade according to Quincy's classification modified by Mongon and Di Constanzo. Survival and healing of "extremely severe" grade intoxication can only be obtained through a surgical intervention within the first hours; a laparotomy will indicate the depth of the lesions, which is not determined by endoscopy, and will consist of Celerier's stripping method and if necessary a gastrectomy, more seldom a cephalic duodeno-pancreatectomy. Only the surgical excision of necrotic tissues can prevent the occurrence of lethal complications like oesophageal or gastric perforations and septic shocks. The analysis of the literature from 1975 up to now gives us information on the methods and the results of these different therapeutic approaches.

Adult↗
PubMed1992

[Current status of poisoning by ingestion of caustics: apropos of a series of 49 cases].

The authors report the history of 49 patients, admitted to an intensive care unit after a caustic or corrosive ingestion. This series follows a similar one, related in 1979. An update is made for early evaluation and management, based on patients classification in three groups: severe cases, moderate cases, mild cases. Clinical and biological data, treatment and outcome for the three groups are related. The frequency and gravity of these poisonings appear to be the same as in the first series, with poor prognosis for extreme emergencies and high risk of oesophageal or gastric stricture for important forms. In this population, 20% of extreme emergencies have favorable outcome with early major surgical procedure.

Adolescent↗
PubMed1991

Increased survival after treatments with anticancer agents of Chinese hamster cells expressing the human Mr 27,000 heat shock protein.

A family of 10 thermoresistant cell lines cloned from Chinese hamster cells transfected with a plasmid containing the structural gene for the small human Mr 27,000 heat shock protein (HSP27) was used to assess the putative role of this heat shock protein in chemoresistance. These cells express varying amounts of human HSP27 in addition to the normal level of endogenous hamster HSP27. As previously observed in the case of thermoresistance, a significant positive linear correlation (P less than 0.05) was found between cell survival in response to doxorubicin and the total amount of HSP27 expressed. Some clones were also examined for resistance to other drugs and chemicals. A statistically significant increased survival relative to the parental cells was observed following treatment with daunorubicin (three clones studied), colchicine, vincristine, actinomycin D, hydrogen peroxide, and sodium arsenite (one clone studied). However, the clone which expressed the highest level of HSP27 was as sensitive as control cells to the cytotoxic action of bis-chloronitrosourea and 5-fluorouracil. The relationship between HSP27 overexpression and increased resistance to cytotoxic agents was also evaluated in three independent pooled cell populations stably transformed with both the human HSP27 and the xanthine-guanine phosphoribosyltransferase gene and selected on the basis of resistance to mycophenolic acid and aminopterin. The results indicated that these cells survived significantly better than the control cells transfected with the marker gene only when exposed to doxorubicin. HSP27-mediated cellular protection was not associated either with decreased drug accumulation or with overexpression of P-glycoprotein. It is suggested that HSP27 might be involved in some form of chemoresistance and could participate in the development of clinical resistance to antineoplastic drugs.

Animals↗
PubMed1991

Phosphorylation of HSP27 during development and decay of thermotolerance in Chinese hamster cells.

The small molecular weight heat shock protein HSP27 was recently shown to confer a stable thermoresistant phenotype when expressed constitutively in mammalian cells after structural gene transfection. These results suggested that HSP27 may also play an important role in the development of thermotolerance, the transient ability to survive otherwise lethal heat exposure after a mild heat shock. In Chinese hamster O23 cells increased thermoresistance is first detected at 2 h after a triggering treatment of 20 min at 44 degrees C, attains a maximum at 5 hours, and decays thereafter with a half-life of 10 h. We found that the development and decay of transient thermotolerance cannot be solely explained on the basis of changes in the cellular concentration of HSP27. The cellular HSP27 concentration is not increased appreciably at 2 h after heat shock and attains a maximum at 14 h. Similar results were obtained in the case of another heat shock protein, HSP70. HSP70 follows slightly faster kinetics of accumulation (peaks at 10 h) and decays much more rapidly (ti/2 = 4h) than HSP27 (t1/2 = 13h). HSP27 has 3 isoelectric variants A, B, and C of which B and C are phosphorylated. In cells maintained at normal temperature, HSP27A represents more than 90% of all HSP27. Shifting the cell culture temperature from 37 to 44 degrees C induces the incorporation of 32P into the more acidic B and C forms, a process that occurs very rapidly since the reduction in the concentration of the A form and a corresponding increase in the level of B and C is detectable by immunoblot analysis within 2.5 min at 44 degrees C. Analyses performed at various times during development and decay of transient thermotolerance revealed a close relationship between the effect of heat shock on HSP27 phosphorylation and cell ability to survive. For example, fully thermotolerant cells (5 h post-induction) are refractory to induction of HSP27 phosphorylation by a 20-min heat shock. The induction of HSP27 phosphorylation was also studied in a family of clonal cell lines of O23 cells that are thermoresistant as a result of the constitutive expression of a transfected human HSP27 gene. In these thermoresistant cells, phosphorylation of the endogenous hamster HSP27 is induced to a level comparable to that found in the thermosensitive parental cells. However, phosphorylation of the exogenous human protein, which represents more than 80% of total HSP27 in these cells, was much less induced.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Improved electronic gate technique, for particle counting and sizing in liquids.

Particle counting and measurements of particle size distributions in liquids can be based on pulse height analysis of signals obtained from a changing gate impedance, upon particle transition. Signal-to-noise ratio is markedly improved, making use of a four-electrode detector. An instrumentation amplifier with a high-pass filter is used as a preamplifier. Cylindrical electrodes and a coaxial aperture location result in a decreased detector capacitance, lowering the signal detection level and contributing to improved pulse shape. Volume sampling is flexible and accurate, making use of a stepping motor actuated digital sampling system. A newly developed baseline restorer, combined with a log-antilog amplifier circuit, allows for linearisation of the pulse height/particle size relationship.

Electronics↗
PubMed1991

Reduction of primary posttraumatic adhesion formation with the prostacyclin analog iloprost in a rodent model.

Recent evidence suggests that inhibition of postsurgical adhesion formation may be effected by modulation of the activities of inflammatory cells contributing to mesothelial repair. Iloprost, a stable analog of prostacyclin, has been shown to exert vasodilatory, antiinflammatory, fibrinolytic, and antithrombotic influences. To determine whether these properties of iloprost might protect mesothelial surfaces from perioperative damage and hence prevent adhesion formation, we evaluated the effect of iloprost on peritoneal healing in a hamster model for primary pelvic injury. Perioperative iloprost therapy significantly reduced posttraumatic adhesion formation when compared with that in vehicle-treated controls. Dose-response studies demonstrate adhesion prevention with doses ranging from 0.04 to 4 mg/kg per 8 hours given subcutaneously over the course of 3 days. These data demonstrate that iloprost is a potent positive modulator of peritoneal healing after pelvic trauma. Further studies to characterize the potential application of iloprost as an adjuvant in reproductive surgery are indicated.

Animals↗
PubMed1991

Synergistic effect of intraperitoneally administered calcium channel blockade and recombinant tissue plasminogen activator to prevent adhesion formation in an animal model.

Previous reports have shown the benefits of calcium channel blockers and recombinant tissue plasminogen activator to prevent postoperative adhesion formation in animal models. To assess the potential benefit of synergistic therapy for the prevention of postoperative adhesion formation, these agents were studied in a rabbit uterine horn model. Four groups of New Zealand White rabbits (n = 8 per group) had a bilateral devascularization injury to the uterine horns. Before closure saline solution, verapamil hydrochloride (2.5 mu/kg/hour), recombinant tissue plasminogen activator (4 mg total dose), or a combination of verapamil and recombinant tissue plasminogen activator at the stated doses were instilled by means of an Alzet osmotic pump x 200 hours. Adhesion scores were evaluated after this time period by estimating the total uterine horn surface involved in adhesions at a terminal laparotomy and by clinically grading the response to determine whether minimal adhesions formed. Results of the total uterine horn surface scores were (mean score +/- SE): saline solution, 44% +/- 3.7%; verapamil, 19% +/- 4.8%; recombinant tissue plasminogen activator, 11% +/- 3.6%; combined, 3% +/- 1% (p less than 0.01 to control and p less than 0.05 to single-drug therapy). Results of the number of animals per group with minimal adhesions were as follows: saline solution, 0; verapamil, 1; recombinant tissue plasminogen activator, 3; combined, 8 (P less than 0.01). These results show a synergistic benefit of verapamil and recombinant tissue plasminogen activator to prevent postsurgical adhesion formation when delivered via the intraperitoneal route.

Analysis of Variance↗
PubMed1991

Mechanism of analgesia induced by hypnosis and acupuncture: is there a difference?

Hypnosis and acupuncture can alleviate experimentally induced pain but the mechanism of analgesia remains unclear for both techniques. Experimental pain was induced by cold pressor test (CPT) in 8 male volunteers. Analgesic effect of hypnosis (HA) and acupuncture (AA) was assessed before and after double-blind administration of placebo or naloxone, in a prospective, cross-over study. We found that pain intensity was significantly lower with HA as compared with AA, both with naloxone (P less than 0.001) and placebo (P less than 0.001). Within HA or AA groups, pain scores did not differ significantly when naloxone or placebo was administered. During AA, however, pain scores were similar to control values when naloxone was given (P = 0.05) but decreased significantly with placebo (P less than 0.002). Analog scales for pain intensity and pain relief showed a good correlation (r = 0.94). Plasma levels of beta-endorphins did not change significantly in any combination. Heart rate, peripheral arterial blood pressure and skin conductance were very insensitive indices to assess pain intensity or relief, as well as intensity of acupuncture stimulation or depth of hypnotic trance. We conclude: (1) HA and AA can significantly reduce pain from CPT, and HA is more effective than AA: (2) HA and AA are not primarily mediated by the opiate endorphin system; and (3) plasmatic levels of beta-endorphins are not significantly affected by either HA or AA nor by naloxone or placebo administration.

Acupuncture Analgesia↗
PubMed1991

Penetration of zona-free hamster oocytes by ejaculated cryopreserved gorilla spermatozoa.

Semen obtained by electroejaculation from two lowland gorillas were cryopreserved in TEST yolk to evaluate the ability of spermatozoa to penetrate zona-free hamster oocytes. Thawed semen was processed through a two-layer Percoll density gradient to obtain motile spermatozoa for the SPA. The processed sperm penetrated greater than 25% of the zona-free hamster oocytes. Thus, the use of TEST yolk to cryopreserve gorilla semen and processing the thawed semen through Percoll gradient to concentrate motile spermatozoa may facilitate sperm capacitation and the ability to penetrate oocytes.

Animals↗