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Biomedical subjects

M Martin

Publications and source records attributed to M Martin.

At least 703 records · Page 39Linked to original sources
PubMed1989

Emergency department sonography by emergency physicians.

A retrospective study was conducted to examine whether emergency physicians can perform accurate ultrasonography that influences the diagnosis and treatment of selected disorders in the emergency department (ED). The physicians acquired a moderate level of expertise in sonography using a series of practical demonstrations and lectures. Patients with symptoms suggestive of cardiac, gynecologic, biliary tract, and abdominal vascular disease periodically underwent ED sonography. The initial interpretation was used as a diagnostic adjunct to subsequent therapy. The accuracy of positive sonographic findings was assessed by confirmatory testing, formal review, or confirmatory clinical course. Emergency physicians were able to diagnose correctly (1) the presence and approximate size of pericardial effusions, (2) the presence or absence of organized cardiac activity in patient with clinical electrical mechanical dissociation, (3) the presence or absence of intrauterine pregnancy in pregnant patients with lower abdominal/pelvic complaints, (4) the position of intrauterine devices in patients with suspected uterine perforation, (5) the presence of gallstones in patients with suspected biliary tract disease, and (6) the presence and size of abdominal aortic aneurysms in patients with pulsatile masses or unexplained abdominal pain. It was concluded that reliable sonography which influences diagnosis and therapy can be performed by emergency physicians and that sonography should become a standard procedure in EDs.

Aorta, Abdominal↗
PubMed1989

Collagen synthesis and deposition in cultured fibroblasts from subcutaneous radiation-induced fibrosis. Modification as a function of cell aging.

Acute local gamma-irradiation of porcine skin induces, as in human skin, extensive mutilating sclerosis, characterized by continuous expansion of the fibrosis invading the adjacent muscle and by accumulation of extracellular matrix macromolecules. Collagen synthesis, content, and types were studied by measuring the incorporation of the radiolabeled precursor [3H]-proline into confluent primary cultures and subcultures of porcine fibroblasts obtained from normal and irradiated fibrotic dermis. A significant increase in collagen biosynthesis and deposition, with a preferential enhancement of type III collagen, was observed in primary cultures of fibrotic fibroblasts when compared to those of normal dermis. However, the percentage (36%) of neosynthesized collagen in relation to the total neosynthesized non-collagenous and collagenous proteins remained unchanged. In subcultures of normal cells, collagen synthesis and content remained constant until about the 10th passage and then progressively declined until death of the fibroblasts, at around the 15th passage. During the senescence phase, normal fibroblasts acquired the capacity to synthesize higher levels of non-collagenous proteins. On the contrary, collagen synthesis and content diminished in subcultures of fibrosis-induced fibroblasts from the second passage, and then progressively declined as a function of aging; particularly the ratio of type III to type I collagen returned to normal values from the second passage. Moreover, these fibroblasts did not become senescent, persisted in synthesizing low levels of collagen, and acquired later (around the 40th passage) a higher capacity to synthesize non-collagenous proteins. These results demonstrate that primary cultures of porcine fibroblasts obtained from normal or radiation-induced fibrotic dermis reproduce the in vivo situation. The results strongly suggest that: 1) the modification of collagen synthesis, content, and types observed in primary cultures of fibroblasts might be due to factors causing long-lasting changes in phenotypic expression and/in stimulation of the expansion of some fibroblast clones engaged in the accelerated synthesis of extracellular matrix macromolecules, such as collagen or non-collagenous proteins. 2) the rapid decrease in this active capacity to synthesize and accumulate collagen, observed in subcultures of fibrosis-induced fibroblasts, might be related to the loss of some activation factors or to the dedifferentiation of the cells. 3) the switch from collagen to non-collagenous protein synthesis during later subcultures of fibroblasts obtained from radiation-induced fibrosis, might be due to molecular modification at the transcriptional or DNA level.

Animals↗
PubMed1989

Calibration curves for size-exclusion chromatography: description of HPLC gels in terms of porous fractals.

We have tested the proposition that porous media used in protein size exclusion chromatography are surface fractals. The data obtained in the calibration of classical gels (Sephacryl and Sepharose) and of HPLC gels (TSK SW and PW) using a wide range of protein sizes, have been analyzed within the framework of this theory. While the model does not apply to classical gels, it seems that HPLC gels can be described as fractals in the range of protein sizes. This finding has interesting implications for the calibration procedure.

Calibration↗
PubMed1989

Lethal cardiac toxicity after cisplatin and 5-fluorouracil chemotherapy. Report of a case with necropsy study.

This article presents a patient affected with epidermoid carcinoma of the soft palate who developed a dilated myocardiopathy with aortic embolism and fatal left cardiac failure after treatment with cisplatin (100 mg/m2, day 1) and 5-fluorouracil (1 g/m2/day i.v. days 2-6). The postmortem necropsy study showed diffuse interstitial edema and intracytoplasmic vacuolization of myocytes, without inflammatory changes. These findings were interpreted as acute toxic myocardiopathy, probably due to 5-fluorouracil treatment. Although the patient also received cisplatin, metoclopramide, allopurinol, thiethylperazine, and amitriptyline, before the onset of clinical symptoms, these drugs were not considered to play an important role in the production of this cardiopathy because of the dosage, necropsy findings, and lack of previous report.

Aortic Diseases↗
PubMed1989

Abnormal proliferation and aging of cultured fibroblasts from pigs with subcutaneous fibrosis induced by gamma irradiation.

In vivo, fibrotic disorders, which may be due either to injury or disease, are characterized by overproliferation of fibroblasts and overproduction of connective tissue. In vitro, however, most of the fibrotic cell lines studied exhibited no differences in growth potential compared with control cell lines derived from normal skin. In the present study, we investigated the in vitro behavior of fibroblasts derived from pigs with subcutaneous fibrosis induced by gamma irradiation. The cells were isolated from the scar tissue six to 20 months after irradiation. In primary cultures, the cells derived from the fibrotic lesions exhibited greater attachment efficiency and faster proliferation than those of the cells derived from the normal skin of the same animal. In long-term cultures, the differences between normal and fibrotic cells were still greater: the normal skin cells underwent 17 population doublings and then died, whereas the fibrotic cells exhibited a prolonged lifespan, and were still actively proliferating after 80 population doublings. Cell morphology and the number of chromosomes were modified throughout subcultures. These results imply that in the scar tissue active fibrotic cell proliferation continued for years after irradiation and that this activation was expressed in vitro. Therefore, in this pig fibrosis model, the data acquired in the present in vitro studies closely resemble that obtained from earlier in vivo observations.

Animals↗
PubMed1989

Combined treatment with gonadotrophin releasing hormone agonist and gonadotrophins in poor responders to hyperstimulation for in vitro fertilization (IVF): clinical and endocrine results.

Seventy three cycles of combined gonadotrophin releasing hormone (GnRH) agonist/gonadotrophin treatment for IVF controlled ovarian hyperstimulation in previous poor responders to standard ovarian hyperstimulation therapy are reported. Oocyte numbers obtained were better than the previous average results, but were similar to the previous best response. In general more oocytes than the previous mean could be expected but low order responders were not transformed into high order responders. Pregnancies did occur in this difficult group of patients but the rate was modest. Because of a reduction in cancelled cycles, patients might reduce their total costs in time and gonadotrophin used, however this treatment is not a panacea for the true low order responder.

Adult↗
PubMed1989

Hypothalamic-pituitary-adrenal and -thyroid axis dysfunctions and decrements in the availability of L-tryptophan as biological markers of suicidal ideation in major depressed females.

Several neurochemical correlates of suicide were recently detected. Some authors found increased disorders in the hypothalamic-pituitary-adrenal (HPA) and -thyroid (HPT) axes and disturbances in serotonergic neurotransmission in suicidal patients. In order to investigate the biological correlates of suicidal ideation, we measured the following: basal thyrotropin-secreting hormone (TSH), free thyroxine (FT4), pre- and postdexamethasone cortisol, adrenocorticotropic hormone (ACTH) levels, the circulating concentrations of total L-tryptophan (L-TRP) and the ratio between L-TRP and competing amino acids (CAA). The subjects were 17 suicidal and 17 nonsuicidal major depressed females matched for age and severity of illness. We found no significant differences in any of the above-mentioned biological data between patients with suicidal ideation and those without.

Adrenocorticotropic Hormone↗
PubMed1989

Sex-linked differences in cortisol, ACTH and prolactin responses to 5-hydroxy-tryptophan in healthy controls and minor and major depressed patients.

Some researchers have found that the administration of 5-hydroxytryptophan (5-HTP) results in increased cortisol secretion in major depressives but not in healthy controls. Other authors observed gender-related differences in cortisol responses to 5-HTP in major depressives. In order to investigate the pituitary/adrenal responsivity to 5-HTP, the authors measured cortisol, adrenocorticotropic hormone (ACTH) and prolactin (PRL) in 30 healthy controls and in 90 depressed patients; the hormone levels were determined in baseline conditions and 60, 90 and 120 min after 125 mg L-5-HTP (orally, non-enteric coated). We found that healthy men had significantly higher cortisol responses to L-5-HTP than healthy women. In the major depressives with melancholia and/or psychotic features these differences were reversed: women exhibited significantly higher cortisol and PRL responses than men. In the female group the most severely depressed patients had increased cortisol and PRL responses to L-5-HTP. The amplitudes of the cortisol, ACTH and PRL responses to L-5-HTP were significantly and positively correlated. It was concluded that the central serotonergic regulation of ACTH and PRL is significantly different between the sexes and between healthy controls, minor depressives and severely depressed patients.

5-Hydroxytryptophan↗
PubMed1989

Probing depth at re-evaluation following initial periodontal therapy to indicate the initial response to treatment.

9 adult subjects with severe periodontitis were monitored following oral hygiene instruction and a single episode of crown and root debridement. Baseline recordings for probing attachment level were obtained both immediately pre-instrumentation and immediately post-instrumentation. Sites with gain, no change or loss of probing attachment level at 3 and 12 months compared to both pre- and post-instrumentation were identified. The classification was based upon the use of triplicate recordings at each time point, a site-specific standard deviation for measurement variability, and the requirement of a minimum of 1.0 mm change. The relative frequencies of gain, no change, and loss of probing attachment were then calculated for sites of various residual probing depths at 3 and 12 months. This was performed to evaluate if a given probing depth at re-evaluation, e.g., 7.0-7.5 mm, could be used as an indicator of the need for supplementary treatment following the initial therapy, based upon the observed probing attachment changes compared to baseline. As an example of the results of the present study, 60% of sites with residual probing depths of 7.0-7.5 mm showed probing attachment gain greater than or equal to 1.0 mm compared to the post-instrumentation baseline, and only 2% had undergone probing attachment loss greater than or equal to 1.0 mm. The overall results suggest that a relatively deep residual probing depth at re-evaluation following initial therapy, by itself, provides little evidence of lack of improvement compared to baseline. On this basis, the use of a specific probing depth at 3 or 12 months following treatment as a yardstick for the provision of supplementary treatment may not be justified.

Adult↗
PubMed1989

Identification of a locus controlling expression of luminescence genes in Vibrio harveyi.

Mutagenesis with transposon mini-Mulac was used to identify loci containing genes for bioluminescence (lux) in the marine bacterium Vibrio harveyi. Transposon insertions which resulted in a Lux- phenotype were mapped to two unlinked regions of the genome. Region I contained the luxCDABE operon which was previously shown to encode the enzymes luciferase and fatty acid reductase, which are required for light production. The other locus, region II, which was identified for the first time in this study, appeared to have a regulatory function. In Northern blot analysis of mRNA from mutants with defects in this region, no transcription from the luxCDABE operon could be detected. Strains with transposon-generated lux::lacZ gene fusions were used to analyze control of the transcription of these regions. Expression of luminescence in the wild type was strongly influenced by the density of the culture, and in strains with the lacZ indicator gene coupled to the luxCDABE operon, beta-galactosidase synthesis was density dependent. So, transcription of this operon is responsive to a density-sensing mechanism. However, beta-galactosidase synthesis in strains with lacZ fused to the region II transcriptional unit did not respond to cell density. The organization and regulation of the lux genes of V. harveyi are discussed, particularly with regard to the contrasts observed with the lux system of the fish light-organ symbiont Vibrio fischeri.

Blotting, Southern↗
PubMed1989

Diastolic function after cardiac and heart-lung transplantation.

The mechanical efficiency of left ventricular contraction and relaxation, the asynchrony of the onset of left ventricular relaxation, the time constant of left ventricular isovolumic pressure decay, and left ventricular chamber and myocardial stiffness were analysed in 32 patients after cardiac (24) and heart-lung transplantation (8). After cardiac transplantation left ventricular myocardial stiffness was increased and a mild degree of incoordinate contraction and relaxation was seen. In contrast, after heart-lung transplantation diastolic function was almost normal. Impairment of passive diastolic properties was significantly related to the ischaemic time of the donor heart and the donor's age. The index of left ventricular asynchrony was related to the ischaemic time and the recipient's age. The interval between transplantation and study did not influence the number of rejection episodes. This study confirms the presence of diastolic dysfunction after cardiac transplantation. Impairment of diastolic function seems to be related to the ischaemic time of the donor heart and to a mismatch between the size of the donor heart and the recipient's needs.

Adolescent↗
PubMed1989

Insulin and renal sodium retention in obese adolescents.

The effect of insulin on the renal handling of sodium was studied in obese and nonobese subjects by using euglycemic hyperinsulinemia. Seven water-loaded obese (14-19 years old) and five nonobese young adults (18-21 years old) had insulin given intravenously at a rate of 40 munits/m2/min. Blood glucose and creatinine clearance were not altered by euglycemic hyperinsulinemia in either the obese or the nonobese group. Hyperinsulinemia resulted in a significant decrease in urinary sodium excretion in both groups of subjects (by 54.2 +/- 3% [mean +/- SEM] in the obese and by 50.9 +/- 3.1% in the nonobese group). However, the amount of glucose required to maintain euglycemia was significantly less in the obese versus nonobese group, 89.5 +/- 6.2 versus 329.2 +/- 16 mg glucose/m2/min (p less than 0.001). There was no relation in either group between the amount of glucose required to maintain euglycemia and the change in urinary sodium excretion. On a separate day, all of the obese subjects underwent 3 hours of water diuresis but without insulin. There was no change in urinary sodium excretion with sustained water diuresis alone. However, when compared with the nonobese group, the obese group of subjects had a significantly higher resting mean arterial pressure, heart rate, and plasma norepinephrine concentration; during the insulin clamp, neither group experienced a significant change in mean arterial pressure or heart rate, and only the nonobese group experienced an increase in plasma norepinephrine. In obese subjects, we have found, despite the presence of insulin resistance to carbohydrate metabolism, that euglycemic hyperinsulinemia was associated with a normal decrease in urinary sodium excretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Hormonal regulation of estrogen receptor messenger ribonucleic acid in T47Dco and MCF-7 breast cancer cells.

Using a combination of hormone-binding assays, immunologic techniques, and mRNA hybridizations we have measured the estrogen receptor (ER) content and studied the hormonal regulation of ER mRNA in one estrogen responsive and one estrogen unresponsive breast cancer cell line, MCF-7 and T47Dco, respectively. Estradiol binding could be detected in cytosol from MCF-7 cells but not in T47Dco cells. However, when measured by an enzyme-linked immunosorbent assay, T47Dco cells were found to contain approximately 15 fmol ER/mg cytosolic protein or 10% of the ER content in MCF-7 cells. Immunologically reactive ER in T47Dco cells was indistinguishable in size (approximately equal to 68 KD) from the ER in MCF-7 cells, as shown by Western blotting using a monoclonal antihuman ER antibody. Quantification of ER mRNA in MCF-7 and T47Dco cells indicated that T47Dco cells contained approximately 50% of the ER mRNA levels found in MCF-7 cells. This basal level of ER mRNA in T47Dco cells was not decreased by estradiol treatment, as opposed to in MCF-7 cells where estradiol caused 40-60% decrease in the ER mRNA expression. Also, estradiol did not increase the progesterone receptor (PR) mRNA levels in T47Dco cells whereas in MCF-7 cells an approximately 5-fold increase of the PR mRNA levels occurred after estradiol treatment. However, incubation of the cells with the synthetic progestin R5020 decreased the ER mRNA levels to approximately the same degree in both cell lines. In conclusion, we have shown that estrogen down-regulates ER mRNA and up-regulates PR mRNA in MCF-7 cells. Neither of these estrogenic effects were seen in T47Dco cells. It appears that the steroid-resistance in T47Dco cells does not occur as a consequence of a complete absence of ER mRNA or protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Blotting, Northern↗
PubMed1989

Fibronectin and glycosaminoglycan synthesis by fibrotic pig fibroblasts in primary culture.

Synthesis of fibronectin and glycosamingoglycans (GAGs) was studied in fibroblasts from pigs with post-irradiation subcutaneous fibrosis. Fibrosis was developed in the femoral muscle by local gamma irradiation with a dose of 60 Gy. Normal fibroblasts were obtained from the healthy skin of the same animal. To measure GAG and fibronectin synthesis fibrotic and normal fibroblasts were labeled with 3H-glucosamine, 35S-sulfate and 35S-methionine. Fibrotic fibroblasts synthesized 2.5 times as much fibronectin as normal skin fibroblasts but total protein synthesis did not change. Parallel enhanced secretion of hyaluronic acid and dermatan sulfate into the cell culture medium were also observed. GAGs from the pericellular layer of trypsin-digested fibrotic fibroblasts exhibited increased 3H incorporation, but reduced 35S-sulfate incorporation. The largest reduction in the latter was observed for heparan sulfate. These results indicate that the fibroblasts from the well developed fibrotic tissue maintain enhanced synthesis of matrix macromolecules in primary cultures. Structural and/or metabolic changes in secreted GAGs, combined with the stimulation of tissue repair by growth factors may be responsible for the excessive deposition of collagen in post-irradiation fibrosis.

Animals↗
PubMed1989

[Streptokinase therapy in a patient with lupus anticoagulant and thrombosis of the A. iliaca externa].

We report on a 26-year-old male who suffered from thrombocytopenia, factor V-deficiency and punctuate hemorrhages during the past. On admission the patient presented with acute left iliac artery occlusion. The walking distance was reduced to 200 m. Laboratory findings showed the existence of a lupus anticoagulant (LAC). As a therapeutical attempt a systemic lysis with high doses of streptokinase (9,250,000 I.E.) was carried out which was followed by a successful catheter lysis (250,000 I.E. streptokinase). During lysis the patient didn't show any unusual hemorrhagic events. Arterial thrombosis together with a lupus anticoagulant can be treated with high doses of streptokinase.

Adult↗