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Biomedical subjects

A Gomes

Publications and source records attributed to A Gomes.

At least 91 records · Page 5Linked to original sources

Isolation, purification and partial characterization of a haemolytic protein from Bidder's organ of toad Bufo melanostictus (Schneider).

A haemolytic protein toxin (BO-HT) from Bidder's organ of toad, B. melanostictus, purified by DEAE-cellulose column chromatography was electrophoretically homogeneous and was glycoprotein in nature (PAS-positive). The molecular weight was estimated to be 14.4 kDa by SDS-polyacrylamide gel electrophoresis. The sensitivity of the haemolysin of different RBC ghost cell preparation was in the order: buffalo > goat > ox > guinea pig > mice > human > chick > rabbit > rat. The haemolytic activity was increased with the decrease in RBC concentration and was produced over a wide range of temperature. Maximum haemolytic effect was produced at 2 hr of incubation. The toxin showed maximum activity at 3 and minimum at 10 pH. Divalent cations (Ca2+, Zn2+, Cu2+, Mg2+) showed inhibitory effect on BO-HT induced haemolysis, whereas sucrose, EDTA, cholesterol, 2-mercaptoethanol and oxygen did not alter the haemolytic activity. Haemolytic activity was reduced by proteolytic enzymes (trypsin, protease) and was totally antagonized by the toad serum.

Animals↗

Pharmacological actions of the venom of the Indian catfish (Plotosus canius Hamilton).

The venom of the common Indian catfish P. canius Hamilton (locally called 'Kanmagur') was examined for its pharmacodynamic activity. The LD50 of the venom in mice was found to be 3.9 mg/kg (ip). At lower doses, the venom produced a positive inotropic effect on toad and rabbit hearts, while at higher doses it produced cardiac arrest. In the isolated guinea pig auricle, the venom increased the rate and amplitude of contraction. The venom increased rat blood pressure--an action antagonised by alpha-adrenergic blocker (phenoxybenzamine). It reduced the rate and amplitude of rat and guinea pig respiration leading to respiratory arrest and death. The venom did not alter the cutaneous capillary permeability of guinea pig but produced vasoconstrictor effect on rat hindquarter perfusion. It induced contractions in several smooth muscle preparations viz., ileum and colon of guinea pig, fundus, uterus and ileum of rat. On isolated guinea pig ileum, the venom produced contraction which was not antagonised by atropine and mepyramine, but was partially antagonised by methysergide associated with a residual contraction which was abolished by SC 19220, a prostaglandin receptor blocker. The venom produced irreversible blockade of electrically induced twitch response on isolated rat phrenic nerve diaphragm and chick biventer cervicis preparation. Haemolysis was not produced by the venom on mice, guinea pig and human RBC (washed).

Animals↗

Isolation of a toxin from jellyfish Acromitus rabanchatu and its effect on skeletal muscle.

A toxin (T-Ar) from the crude extract of jellyfish Acromitus rabanchatu was purified by (NH4)2SO4 fractionation followed by ion-exchange chromatography on DEAE-cellulose column. The mol. wt of T-Ar was found to be about 182,000. T-Ar reversibly blocked the twitch response of rat diaphragm muscle stimulated either indirectly or directly. It also reversibly blocked the twitch responses of chick biventer-cervicis muscle preparations. T-Ar failed to alter the contractures of the denervated rat diaphragm muscle preparation induced by acetylcholine, potassium chloride and caffeine. Similarly, acetylcholine and carbachol-induced contractures on chick biventer-cervicis muscle preparation were not influenced by T-Ar. The T-Ar-induced blockade of twitch responses of rat phrenic nerve-diaphragm was enhanced in high Na+ or low Ca2+ medium, and reduced in low Na+ or high Ca(2+)-containing medium. The results suggest that the toxin (T-Ar) possesses a direct paralysing effect on the muscle membrane.

Acetylcholine↗

Urokinase therapy for thrombosed hemodialysis access grafts.

Urokinase, with or without angioplasty, is an alternative to surgical treatment for the treatment of thrombosed polytetrafluoroethylene vascular access grafts. To evaluate the efficacy and outcome of thrombolytic therapy, all available charts of patients with a thrombosed graft treated at the University of California at Los Angeles Medical Center from June 1988 to August 1991 were reviewed. Twenty-three grafts in 21 patients underwent 43 procedures, 17 thrombolytic and 26 surgical, during this period. Four procedures in the thrombolytic group and the surgical group were patent less than 48 hours. Complications occurred in a significantly higher percentage of the thrombolytic group (11 of 17) than the surgical group (two of 26) (p < 0.001). Using life-table analysis, the primary patency was approximately 40 percent at six months and 20 percent at one year in both groups. Urokinase therapy was significantly more expensive than surgical therapy in this study. This increased cost was the result of ten of 17 patients receiving urokinase for more than eight hours. It is concluded that percutaneous delivery of thrombolytic therapy with angioplasty of any documented lesion is as effective as surgical procedure in the treatment of thrombosed hemodialysis access grafts, thrombolytic therapy is associated with a significantly higher complication rate and urokinase treatment that requires more than six to eight hours to lyse the graft thrombus may not be cost-effective.

Catheters, Indwelling↗

[Hypertensive reaction to exercise. Retrospective studies of 1363 consecutive exercise tests].

OBJECTIVE: To study exercise hypertensive reaction and its relation with rest blood pressure, hypertension type and hypertensive cardiac disease. DESIGN: Retrospective study of treadmill exercise testes (ET) performed from January/89 to June/91: (n: 1703). SETTING: Stress tests Laboratory of Cardiology Service of a Military Hospital. METHODS: 1363 consecutive ET of male subjects, performing at least the 3rd stage of the Bruce protocol, were studied. From each ET record were obtained general data, including the reason for test, medication and the rest and exercise blood pressure. Exercise hypertensive reaction was defined as a Bruce protocol 3rd stage systolic blood pressure above 187 mmHg, which corresponds to mean +2SD of 130 normal male subjects previously studied. The Echocardiograms of non-treated hypertensives, obtained less than a month from ET, were reviewed. The diagnosis of borderline or moderate hypertension was base on the clinical records. RESULTS: 1) The 1363 ET included 132 (9.7%) ET to study hypertensive subjects, and 68 of these had hypertensive reaction. 86 ET were performed by non-treated hypertensive subjects, of whom 73 had Echocardiogram. 43 (3.5%) from 1231 ET performed by non-hypertensive subjects also had exercise hypertensive reaction. 2) The left ventricular (LV) mass index of non-treated hypertensive patients had a positive correlation with exercise systolic pressure (r: 0.45; p < 0.001), more important than with rest blood pressure or exercise systolic pressure response; there was a relation with LV wall thickness, but not with internal ventricular dimensions, that was only observed in hypertensive subjects that also had hypertensive reaction to exercise. 3) Exercise systolic blood pressure was usually normal in borderline and elevated in moderate hypertensives (Qui2: 27.249; p < 0.001). 4) Subjects with exercise hypertensive reaction, but not previously diagnosed as hypertensives, were usually true hypertensives. CONCLUSIONS: 1) Hypertensive peaks seem to be an important determinant factor in LV hypertrophy of hypertension, but its influence is felt only above a certain blood pressure threshold; it results on LV concentric type hypertrophy. 2) Exercise systolic blood pressure had a discrimination power of about 80% to separate borderline and moderate hypertensive subjects. 3) All subjects having an exercise hypertensive reaction must be carefully observed, even if their blood pressure at rest is normal, because most of them are true hypertensive patients.

Adult↗

Immunologic mechanisms in secretory otitis media--recent concepts. Part I.

Increasing evidence has been accumulated in the last few years associating immunological mechanisms in the pathogenesis of secretory otitis media. If immunological processes were found to be involved in both of the previously accepted experimental pathogenic models (Eustachian tube obstruction: microbiologically induced) of the disease, recently published data has provided evidence for a third, not Eustachian tube--or microbiological-dependent, exclusively immunological, experimental model. This suggests that immunological mechanisms are probably always involved in the pathogenesis of a disease that is known to be multifactorial in origin, and thus eventually make Immunology the single most important factor in secretory otitis media. In the present article these recent concepts are extensively reviewed by the authors.

Eustachian Tube↗

[Stapling in surgery of cancer of the rectum. Experience with 100 cases].

The authors relate their experience with 100 cases of anterior resections operated using stapling techniques, 43 with double stapling. Fifty three were males and forty seven females, the youngest being 35 year's old and the oldest 87. The tumour was located at the upper third in 54 cases, at the middle third in 41 and at the lower third in five cases. One hundred anterior resections were executed, fifty of the low type. As to the Dukes classification, 15 were A type, 45 type B, 35 type C and 5 type D. There were no operative mortality until the 30th post operative day. As early post-operative complications there were one case of hemorrhage, two pneumopathies, one urinary retention, one cardio-respiratory insufficiency three cases of fistulae and 6 wound infections. In the last 65 cases only one wound infection and two pneumopathies were found. As late complications there were three anastomotic stenosis (all of them satisfactorily solved with dilatation) and six cases with small degree incontinence for gas and faeces recovering spontaneously. The recurrence rate was 14%; in three it has been possible to proceed with its excision by means of abdominoperineal amputation. They conclude stating that mechanical suturing specially is a good alternative to manual suturing in patients with low rectal tumours.

Adult↗

Detection and distribution of scorpion (Heterometrus bengalensis) venom in rabbit tissues by enzyme-linked immunosorbent assay (ELISA).

ELISA was carried out to detect distribution of scorpion venom in experimental animal tissues. The venom content of different tissues was in the order, liver greater than kidney greater than spleen greater than lung greater than heart greater than diaphragm greater than brain. Tissue distribution of venom antigen in the envenomental subject by ELISA will provide a better approach for serotherapy.

Animals↗

Immunologic mechanisms in secretory otitis media-recent concepts (Part II).

Increasing evidence has been accumulated in the last few years associating immunological mechanisms in the pathogenesis of secretory otitis media. If immunological processes were found to be involved in both of the previously accepted experimental pathogenic models (Eustachian tube obstruction; microbiologically induced) of the disease, recently published data has provided evidence for a third, not Eustachian tube- or microbiological-dependent, exclusively immunological, experimental model. This suggests that immunological mechanisms are probably always involved in the pathogenesis of a disease that is known to be multifactorial in origin, and thus eventually make Immunology the single most important factor in secretory otitis media. In the present article these recent concepts are extensively reviewed by the authors.

Agammaglobulinemia↗

Lethal and haemorrhagic activity of Russell's Viper venom--neutralization by polyvalent, monovalent and toxoid antiserum.

Lethal and haemorrhagic activity of Russell's Viper venom was compared against polyvalent bivalent commercial antiserum and monovalent antiserum raised in rabbit. Formaldehyde-detoxified venom offered 7-fold protection against lethal activity and 12.5-fold against haemorrhagic activity of the venom. Whole venom and formaldehyde-detoxified venom along with Freund's complete adjuvant, injected in rabbits produced high titre antiserum. Amongst all the six antiserum tested, the monovalent antiserum raised in rabbit, showed maximum precipitating bands in immunogeldiffusion and immunoelectrophoresis. The toxoid-antiserum offered maximum protection against the venom-induced lethality and the monovalent antiserum offered maximum protection against haemorrhagic activity.

Animals↗

[Pressure response to dynamic exercise and antihypertensive therapy].

OBJECTIVES: To study the exercise systolic pressure (SP) in hypertensive patients, its relation with left ventricular (LV) mass and the efficacy of its control by some antihypertensive drugs. DESIGN: To study the echocardiogram (ECHO) and exercise test (ET) in hypertensives (HT), before and after rest blood pressure (BP) control. SETTING: Out-patient cardiology clinic in a military hospital. METHODS: 53 male moderate HT, 30 to 60 years old, without other pathology, were studied with ECHO and ET. 28 HT repeated ET after rest BP control: Group A--Diuretic (Hchlt/Triam), n: 7; Group B--Atenolol, n: 10; Group C--Nifedipine, n: 11. RESULTS: 1. There was a positive correlation between LV mass index and exercise SP (r: 0.37; p less than 0.01), but not rest blood pressure. 2. Exercise test duration was increased only in group C. 3. Hypertensives with rest BP control had also normal exercise SP in group B, but not in groups A or C (Qui2: 11 735; p less than 0.001). CONCLUSIONS: 1. Exercise systolic blood pressure seems to be more important than rest blood pressure to the development of LVH in hypertensive patients. 2. The observed increase of exercise capacity in Nifedipine group must be considered in the treatment of physically active hypertensives. 3. Hypertensives with rest BP controlled by Atenolol have also, very probably, a normal exercise systolic pressure. 4. In physically active HT with rest BP controlled by Diuretic or Nifedipine may be useful an exercise test to evaluate exercise systolic pressure.

Adult↗

Histamine, 5-HT & hyaluronidase in the venom of the scorpion Lychas laevifrons (Pock).

Factors involved in the pathophysiological changes such as severe pain, burning sensation, redness, swelling and edema in case of the scorpion L. laevifrons were investigated. The presence of pain-producing autacoids histamine 2.1 +/- 0.18 micrograms/mg and 5-HT 0.23 +/- 0.1 micrograms/ml was confirmed by thin layer chromatography and bioassay. Histamine releasing substance was detected in vitro in the chopped guineapig lung. Venom also contained hyaluronidase 5 x 10(-4) N-acetyl-D-glucosamine released/h/mg, which facilitates spread of the toxic principles in the tissues. It is concluded that histamine, 5-HT, histamine-releasing factor and hyaluronidase are partly involved in the pathophysiological changes induced by the venom. It is suggested that mepyramine and cyproheptadine may prove useful in the management of scorpion envenomation.

Animals↗

Pharmacological actions of tentacle extract of the jellyfish, Acromitus rabanchatu, occurring in the Bay of Bengal.

Tentacle extract of A.rabanchatu, produced a fall of blood pressure in cat, rat and guinea pig. Hypotension produced in cat remained unantagonized by blockers of acetylcholine, histamine and 5-HT. On isolated guinea pig heart, the extract significantly reduced the rate and amplitude of contraction leading to irreversible cardiac arrest. In cats and rats, the respiratory rate and amplitude was decreased significantly and resulted in temporary apnoea. The extract also produced vasoconstriction in perfused rat hindquarter preparation and increased cutaneous capillary permeability. The extract produced contraction in several isolated smooth muscle preparations. Contraction on guinea pig ileum was partly antagonized by atropine and cyproheptadine. On isolated rat phrenic nerve diaphragm and chick biventer cervicis, the extract produced irreversible blockade of the electrical stimulation-induced twitch responses. Haemolytic and myonecrotic activity was exhibited by the extract. LD50 was found to be 7.7 mg/kg (iv, mice).

Animals↗

Glycaemic effects of tentacle extract of the jellyfish Acromitus rabanchatu (Annandale).

Tentacle extract of the common jellyfish A. rabanchatu, caused glycaemic alteration in fasting rabbits. Intravenous administration of the extract produced a significant rise followed by a significant fall in blood sugar level. Glucose tolerance in rabbits was also significantly increased. Extract-mediated hypoglycaemic response was fully abolished in alloxan diabetic rabbits. Preliminary separation on Sephadex G 50 indicated the hypoglycaemic factor to be a non-lethal protein of molecular weight less than 20 kDa. Heat treatment of extract and G 50 separated fraction P2 demonstrated total loss of hypoglycaemic activity.

Animals↗

[Outcome beyond the 1st trimester of 305 pregnancies conceived by fertilization in vitro].

The obstetrical outcome of 305 pregnancies obtained by in vitro fertilization were reviewed: out of 275 pregnancies following fresh embryo transfers, 205 (74.5%) were single, 64 (23.3%) double and 6 (2.2%) triple). We observed increased frequencies of high blood pressure linked to older maternal age, bleeding in the late pregnancy and breech presentation, which could be associated to abnormal insertion of umbilical cord and/or placenta. Multiple pregnancies, especially the triple ones, are of the highest risk (intra-uterine growth retardation, low birth weight). Nevertheless the total fetal mortality remains low in our experience. Data about 22 pregnancies following cryopreserved embryo transfer, 5 after oocyte donation and 3 therapeutic abortions are also given.

Adult↗

Isolation, purification and immunological evaluation of toxin Hb from scorpion Heterometrus bengalensis (C.L. Koch) venom.

Toxin-Hb, a lethal toxic antigenic protein, isolated from the venom of H. bengalensis by CM-cellulose ion-exchange chromatography was a heat labile basic protein with a molecular weight of 10 kDa. It produced irreversible blockade on the isolated rat phrenic nerve diaphragm and chick biventer cervicis. LD50 of toxin Hb was 0.48 mg/kg (iv) in mice. Antiserum was raised in mice by hyperimmunization against toxin Hb. Antitoxin Hb antiserum was immunologically potent as revealed by immunogel-diffusion and immunoelectrophoresis. Five fold protection against the lethal action of toxin Hb was achieved by the antiserum. It also effectively antagonised toxin Hb induced neuromuscular blockade on isolated rat phrenic nerve diaphragm and chick biventer cervicis preparations.

Animals↗

Isolation and purification of a lethal scorpion toxin with neuromuscular blocking activity.

Toxin-L a lethal neuromuscular blocking agent was isolated from the venom of the scorpion, Lychas laevifrons (Pocock), by the CM-cellulose ion-exchange chromatography. It was a homogenous, thermolabile and low molecular weight protein. The toxin produced irreversible blockade of indirect stimulation induced twitch responses on innervated rat phrenic nerve-diaphragm and chick biventer cervicis preparation. The toxin did not produce any contractile response on toad rectus abdominis muscle preparation. On chronically denervated rat diaphragm, the toxin failed to alter the responses induced by direct stimulation, exogenous acetylcholine, potassium chloride and caffeine. Acetylcholine and carbachol induced contractions on isolated chick biventer cervicis remained unaltered by the toxin. Neostigmine failed to alter toxin induced neuromuscular blockade on innervated rat diaphragm. The toxin released a significant amount of acetylcholine from innervated rat diaphragm. It may be concluded that the toxin acts presynaptically through the release of acetylcholine, thereby producing neuromuscular blockade.

Animals↗