Our health problems are preventable with education: maternal and child care in the Marshall Islands.
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Communicable Disease Control↗
Biomedical subjects
G Johnson
Publications and source records attributed to G Johnson.
We can do the job ourselves: Marshall Islanders push intensive immunization program.
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Child Health Services↗
Cocaine, pregnancy, and postpartum intracerebral hemorrhage.
An increase in cocaine abuse by pregnant women has been associated with a range of maternal/fetal cardiovascular complications. Intracerebral hemorrhage has been reported as a cocaine-related complication, but has not previously been associated with pregnancy. We report a case of cocaine-associated intracerebral hemorrhage in the postpartum period which complicated the differential diagnosis and management of hypertension and seizures.
Adult↗
Protective effects of a combination thromboxane synthesis inhibitor-receptor antagonist, R-68070, during murine traumatic shock.
The effects of R-68070 were studied in a well-characterized model of drum-induced traumatic shock in rats. R-68070 is a combination thromboxane A2 (TxA2) synthetase inhibitor-TxA2 receptor antagonist. Pentobarbital-anesthetized (50 mg/kg) rats subjected to Noble-Collip drum trauma developed a lethal circulatory shock state characterized by a marked decrease in mean arterial blood pressure (MABP) to about 75 mmHg, resulting in a survival time of 1.58 +/- 0.18 h. This compares with MABP of 120 +/- 4 mmHg 5 h after anesthetization in rats subjected to a sham traumatic shock protocol. Administration of R-68070 (1.5 mg/kg) significantly attenuated the plasma accumulation of the lysosomal protease, cathepsin D (p less than 0.05), as well as free amino-nitrogen concentration (p less than 0.05) and myocardial depressant factor activity (p less than 0.02). Additionally, R-68070 significantly prolonged survival time to 2.85 +/- 0.48 h (p less than 0.015) compared with traumatized rats given only the vehicle. These results suggest that TxA2 may be an important mediator in traumatic shock, and that R-68070 may prove to be a useful therapeutic agent in this situation if given early in the course of the shock state.
Animals↗
Protective actions of a new potent thromboxane receptor antagonist in arachidonate induced sudden death.
Sodium arachidonate (NaAr) at a dose of 1.1 mg/kg injected i.v. is uniformly lethal in rabbits within 5 min. This sudden death is typified by a precipitous drop in mean arterial blood pressure, a dramatic decrease in the circulating platelet count, and by a marked rise in plasma thromboxane A2 (TxA2) concentration as measured by radioimmunoassay of its breakdown product, TxB2. Pretreatment with S-145, a new thromboxane receptor antagonist, at doses ranging from 50 to 500 micrograms/kg resulted in 100% survival of all the rabbits subjected to sodium arachidonate injection. However, at 20 micrograms/kg S-145 only 25% of the rabbits challenged with NaAr survived. S-145 pretreatment also inhibited the decreases in circulating platelet count and in blood pressure associated with the i.v. injection of sodium arachidonate (NaAr). S-145 blunted the rise in plasma TxB2 concentration at all doses. S-145 was also shown to be a potent and long-lasting antagonist of TxA2 receptors in isolated rabbit aortic rings. Our data show that S-145 is a very effective protective agent against NaAr-induced sudden death in rabbits.
15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
Differences in secretion of prostacyclin by venous and arterial endothelial cells grown in vitro in a static versus a mechanically active environment.
The objective of this study was to compare the effect of cyclic tension on prostacyclin secretion by venous and arterial endothelial cells. Early passage endothelial cells from bovine aortas and venae cavae were subjected to cyclic deformation (up to 17% elongation and 60 cycles/min). On posttreatment days 3 and 5 a radioimmunoassay was used to assess supernatant fluids from the endothelial cells for prostacyclin activity. The results indicate that in vitro (1) under static or control conditions, venous endothelial cells secrete significantly more prostacyclin (an increase of 1.5- and 4.8-fold on days 3 and 5, respectively) than do arterial endothelial cells isolated from the same animal and (2) prostacyclin secretion by mechanically deformed venous and arterial endothelial cells was significantly less than static control cultures on days 3 and 5. However, prostaglandin I2 secretion remained at higher levels in cyclically deformed venous endothelial cells than in cyclically deformed arterial endothelial cells. These data suggest that endothelial cells from the vena cava have a greater capacity for prostacyclin secretion than have their aortic counterparts. If these observations are maintained in vivo, greater prostacyclin secretion by venous endothelial cells could represent a homeostatic mechanism aimed at reducing thrombus formation in low-velocity areas of the vasculature.
Arteries↗
Non-nursing duties in theatre: a literature review.
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Humans↗
Identification and evaluation of O-alkyl substituted hydroxamic acids as potent in vitro inhibitors of the hepatic glycine cleavage system and investigation of their action on in vivo central nervous system glycine concentration.
The identification and evaluation of an extensive series of O-alkyl substituted hydroxamic acids as potent in vitro inhibitors of the hepatic glycine cleavage system is described. An investigation of the action of selected examples on the in vitro brain glycine cleavage system and their influence on in vivo plasma and central nervous system glycine concentrations following systemic administration is also reported.
Animals↗
Non-nursing duties in theatre. A need for research?
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Humans↗
Antibody-mediated marrow failure after allogeneic bone marrow transplantation.
Marrow graft failure observed in association with histocompatibility differences between donor and recipient is often attributed to rejection mediated by host-derived cytolytic T lymphocytes. The data presented in this report indicate that persistent host antibodies specific for donor antigen may also mediate graft failure, either by antibody-dependent cell-mediated cytotoxicity (ADCC), or complement-mediated cytotoxicity. In the case of HLA Class I disparity, where all donor cells express the target antigen, the presence of alpha-donor antibody was associated with complete graft failure and death. In the case of ABO blood group antigen disparity, the presence of alpha-donor antibody resulted in erythroid hypoplasia. The latter cases proved informative insofar as they established that host antibodies could persist for more than 18 months after chemoradiotherapy and impair marrow function.
Adult↗
Familial diffuse cystic angiomatosis of bone.
Twelve cases of diffuse cystic angiomatosis of bone are presented in a family over four generations. The inheritance pattern of the disease appears to be one of an autosomal dominant distribution with no skipped generations and equal sex distribution. Individuals affected are clinically asymptomatic. All blood parameters are normal. Roentgenographically, the lesion occurs throughout the length of long bones and is osteolytic, with a thin sclerotic rim. The cortex of the bone is rarely involved and shows no periosteal reaction. Growth plate closure and remodeling are unaffected. The natural history is of increasing sclerosis, resulting in complete obliteration of the cyst with irregular reactive trabeculations. Although it resembles more serious conditions, the condition can be diagnosed clinically and radiographically, making invasive tests and treatment unnecessary.
Adult↗
Prospective evaluation of initially ineffective defibrillation pulses on subsequent defibrillation success during ventricular fibrillation in survivors of cardiac arrest.
The effect of initially ineffective defibrillation pulses on subsequent defibrillation success is not known. Therefore, the voltage, current and energy at the defibrillation threshold were compared with the defibrillation rescue pulse voltage, current and energy that terminated ventricular fibrillation when an ineffective pulse just below the defibrillation threshold had been used initially. This lower amplitude ineffective pulse was termed a "subdefibrillation threshold" pulse. The pulse that restored sinus rhythm after the subdefibrillation threshold pulse was delivered was termed the "subdefibrillation threshold rescue pulse." This comparison was undertaken, intraoperatively, in 14 out-of-hospital cardiac arrest survivors using a sequential-pulse catheter-patch defibrillation system. Each of the 14 patients required higher voltage, current, delivered energy and stored energy for defibrillation with the subdefibrillation threshold rescue pulse than with the defibrillation threshold pulse. The defibrillation threshold voltage was 451 +/- 127 volts compared with a subdefibrillation threshold rescue voltage of 585 +/- 147 volts (p less than 0.00002). The defibrillation threshold current was 5.5 +/- 2.4 amps compared with a subdefibrillation threshold rescue current of 7.2 +/- 2.7 amps (p less than 0.00001). Delivered and stored energies were 10.9 +/- 7.4 and 12.3 +/- 7.2J, respectively, for the defibrillation threshold pulse and were 17.6 +/- 9.4 J (p less than 0.00002) and 20.5 +/- 9.3 J (p less than 0.00005), respectively, for the subdefibrillation threshold rescue pulse. It is concluded that the risk of requiring considerably higher energies than anticipated for defibrillation must be incurred, should defibrillation fail because of an initially insufficient defibrillation pulse.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Properties of the transferrin associated with rat intestinal mucosa.
The transferrin that is isolated from washed intestinal mucosal cell preparations consists partly of a fraction that has properties distinguishing it from serum transferrin. The serum transferrin contaminating mucosal preparations, even when fully saturated with iron and in the presence of proteinase inhibitors, also acquires the properties of the mucosal transferrin when the mucosa is homogenised. The mucosal transferrin is modified by a single cleavage of the polypeptide chain yielding a disulphide-linked peptide of 6550 daltons linked to the parent protein by a disulphide bridge. The amino-terminal sequence of the first 11 residues of this peptide could be aligned with both the known rat and human transferrin carboxy-terminal sequences. In both cases the sequence is preceded by a phenylalanine residue (residue 622 of human transferrin). This suggested that a mucosal chymotryptic enzyme was responsible even though rat transferrin is not susceptible to alpha-chymotrypsin if fully iron-saturated. Since transferrin mRNA is not found in the intestinal mucosa it must be imported from the serum. It remains uncertain whether the modified transferrin is present naturally and plays a role in iron absorption but these findings do indicate the eventual fate of any transferrin imported into an intestinal cell.
Amino Acid Sequence↗
The spectrum of renal disease in Laurence-Moon-Biedl syndrome.
To determine the nature, extent, and severity of renal involvement in Laurence-Moon-Biedl syndrome (obesity, mental retardation, polydactyly, hypogonadism, and pigmented retinal dystrophy), we evaluated 20 of 30 patients with the disorder identified from ophthalmologic records in Newfoundland. The mean age was 31 years, and seven were male. All 20 patients had structural or functional abnormalities of the kidneys or both. Three had end-stage renal disease, with two requiring maintenance hemodialysis. The remaining 17 patients had normal serum creatinine values and estimated creatinine clearances. Half the subjects had hypertension. Fourteen of 17 patients could not concentrate urine above 750 mOsm per kilogram of body weight even after vasopressin, whereas all 10 normal controls could. Urinary pH decreased below 5.3 after ammonium chloride administration in all 15 normal controls, but in only 13 of 18 patients. Calyceal clubbing or blunting was evident in 18 of 19 patients studied by intravenous pyelography; 13 patients had calyceal cysts or diverticula. Seventeen of 19 patients had lobulated renal outlines of the fetal type. Four patients had diffuse renal cortical loss, but only two of these had renal insufficiency. We conclude that Laurence-Moon-Biedl syndrome includes the presence of renal abnormalities.
Adolescent↗
Developments, complications and limitations of catheter-mediated electrical ablation of posterior accessory atrioventricular pathways.
Nineteen patients with posterior accessory pathways and disabling, refractory arrhythmias, underwent catheter ablation using standard defibrillator pulses at energy settings of 150 to 400 J. Accessory pathway ablation was successful in 13 of 19 (68%). Effective catheter ablation correlated with local ventriculoatrial (VA) intervals determined from the coronary sinus catheter at the site of earliest retrograde atrial activation during orthodromic reciprocating tachycardia. In 12 of the 13 successfully ablated patients, the local VA interval was less than 80 ms. In 4 of the 6 unsuccessfully treated patients, the local VA interval was greater than or equal to 80 ms, p less than 0.01. Transient abnormalities noted with the procedure included sinus bradycardia (3 patients), atrioventricular block (5), accelerated junctional rhythm (3), ectopic atrial tachycardia (2), myocardial depression (1), "ischemic" appearing T-wave inversions (10) and hemodynamically insignificant small pericardial effusions (5) Creatine kinase-MB increased from 3 +/- 2 U/liter to 26 +/- 18 U/liter (p less than 0.001), 4 to 8 hours after ablation. In addition, electrical shorts occurring during the ablation procedure in 2 patients were identified and corrected only with oscilloscopic monitoring of voltage and current waveforms. Significant adverse sequelae were seen in 4 patients. Three patients required sternotomy for control of cardiac tamponade secondary to a ruptured coronary sinus and 1 patient had a small posterior left ventricular infarction related to spasm of a right coronary artery extension branch. Coronary sinus rupture correlated with the ratio of catheter diameter to coronary sinus diameter.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Enhanced collagen production by smooth muscle cells during repetitive mechanical stretching.
We examined the effect of repetitive mechanical stretching on smooth muscle cell (SMC) collagen production. Porcine SMCs from passages 3 through 7 were seeded in 35-mm2 flexible-bottomed culture wells at a concentration of 2 x 10(5) cells per well and allowed to attach for 24 hours. The experimental group was placed in a vacuum-operated stress-providing instrument that exerted an average elongation of 25% at maximum downward deflection of the culture plate bottom. The stretched cells (nine wells per day) were subjected to a cyclic force regimen of 10 s of elongation and 10 s of relaxation for five days. The control cells (nine wells per day) were subjected to incubation conditions similar to those in the experimental group but without cyclic stretching. Twenty-four hours before harvesting, serum-free medium containing 50-microCi tritiated proline, an amino acid hydroxylated in collagen (hydroxyproline), and 50 micrograms/mL of ascorbate was added per well. On days 3 and 5 the medium and cells were collected, precipitated with trichloroacetic acid, and then sedimented, lyophilized, and analyzed to separate hydroxyproline and proline. Values for collagen and noncollagen protein were calculated after quantitation of the hydroxyproline and proline concentrations. The results indicate that three-cycle-per-minute stretching coordinately stimulated SMC production of collagen and noncollagen protein. We conclude that pulsatile stretch enhances collagen and noncollagen protein synthesis.
Animals↗
Chronic unilateral optic neuropathy: a magnetic resonance study.
We studied the clinical, electrophysiological, and magnetic resonance imaging (MRI) features of 20 patients with chronic unilateral optic neuropathy (CUON): progressive unilateral visual failure lasting a minimum of 6 months. The patients, 10 male and 10 female, ranged in age from 12 to 77 years (mean 44) and had a mean duration of symptoms of 22 months. All had signs of optic nerve dysfunction. Each patient was studied with MRI using a short TI inversion recovery (STIR) sequence to delineate the optic nerve from surrounding orbital tissue. Three distinct groups of patients with CUON were identified using MRI. In the first group (8/20) the optic nerve was compressed by an extrinsic mass, whereas in the second group (5/20) CUON resulted from an intrinsic tumor of the optic nerve or sheath. In both groups STIR sequences compared favorably with computed tomography in identifying mass lesions. MRI was superior in delineating distortion of the optic nerve by mass or tumor extension beyond the orbit. In the third group (7/20) no mass was evident on MRI. However, STIR sequences revealed altered signal (long T1) in clinically symptomatic nerves. In 4 of the patients T2-weighted cerebral MRI disclosed periventricular lesions suggestive of disseminated white matter disease. We conclude that MRI complements clinical and electrophysiological testing in the assessment of CUON.
Adolescent↗
Cell growth on metallic glasses: the interaction of amorphous metal alloys with cultured neuronal, osteoblast, endothelial, and fibroblast cells.
Ferrous based, corrosion resistant amorphous alloys supported the adhesion and growth of cultured chick neuronal cells, human marrow stromal cells (presumptive osteoblasts), bovine aortal endothelial cells, and hamster kidney fibroblasts. Alloys of compositions Fe60Ni10Cr10P13C7, Fe70Cr10P13C7, and Fe70Cr10P13B7 were found to be suitable. In contrast the crystalline form of these alloys was markedly less effective. Outgrowth of neurites from neuronal cells was promoted by precoating the metal surface with either laminin or neurite promotion factor. The adhesion of osteoblasts and fibroblasts suggests that corrosion resistant metal glasses should be considered as biomaterials useful for orthopedic applications. The adhesion of neuronal cells accompanied by neurite outgrowth indicates that the system might provide a functional interface between the neuromuscular system and an electromagnetic material that could be useful in bionic engineering.
Alloys↗