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Biomedical subjects

S Yasin

Publications and source records attributed to S Yasin.

12 recordsLinked to original sources
PubMed2005

Large tunneling anisotropic magnetoresistance in (Ga,Mn)As nanoconstrictions.

We report a large tunneling anisotropic magnetoresistance (TAMR) in (Ga,Mn)As lateral nanoconstrictions. Unlike previously reported tunneling magnetoresistance effects in nanocontacts, the TAMR does not require noncollinear magnetization on either side of the constriction. The nature of the effect is established by a direct comparison of its phenomenology with that of normal anisotropic magnetoresistance (AMR) measured in the same lateral geometry. The direct link we establish between the TAMR and AMR indicates that TAMR may be observable in other materials showing room temperature AMR and demonstrates that the physics of nanoconstriction magnetoresistive devices can be much richer than previously thought.

Journal Article↗
PubMed2000

Influence of human immunodeficiency virus infection on pelvic inflammatory disease.

OBJECTIVE: To examine the influence of human immunodeficiency virus (HIV) infection on clinical and microbiologic characteristics of pelvic inflammatory disease (PID). METHODS: Forty-four HIV-infected women and 163 HIV noninfected women diagnosed with PID by standard case definition were evaluated by using clinical severity scores, transabdominal sonograms, and endometrial biopsies. After testing for bacterial infections, patients were prescribed antibiotics as recommended by the Centers for Disease Control and Prevention (CDC). RESULTS: Symptoms of PID and analgesic use before enrollment did not differ by HIV serostatus. More HIV-infected women had received antibiotics before enrollment (40.9% versus 27.2%, P =.08), a factor associated with milder signs regardless of serostatus. More HIV-infected women had sonographically diagnosed adnexal masses at enrollment (45.8% versus 27.1%, P =.08), a difference that yielded higher median severity scores (17.5 of 42 points versus 15 of 42 points, P =.07). However, those differences were not significant at the P <.05 level. Mycoplasma (50% versus 22%, P <.05) and streptococcus species (34% versus 17%, P <.05) were isolated more commonly from biopsies of HIV-infected women. Within 30 days after enrollment, HIV-infected women generally responded as well to therapy as HIV-noninfected women did, regardless of initial CD4 T-lymphocyte percentage. CONCLUSION: Among women with acute PID, HIV infection was associated with more sonographically diagnosed adnexal masses. Clinical response to CDC-recommended antibiotics did not differ appreciably by serostatus. Mycoplasmas and streptococci were isolated more commonly from HIV-infected women, but those organisms also might be associated with PID in immunocompetent women.

Adult↗
PubMed1998

Use of adenosine for pharmacological cardioversion of SVT in pregnancy.

Objective: To evaluate the success and safety of adenosine use in treating maternal supraventricular tachycardia (SVT) in pregnancy.Methods: Hemodynamically stable pregnant women diagnosed with supraventricular tachycardia admitted to Jackson Memorial hospital from 1990 to 1995 and treated with adenosine were included in the study. Adenosine was given intravenously with an initial dose of 6 mg, followed by two 12 mg doses as needed. Mothers and fetuses were followed prospectively to assess short-term and long-term effects of the treatment.Results: A total of four pregnant patients were treated with adenosine for medical cardioversion of SVT. All patients were hemodynamically stable upon arrival to the maternity ward and were successfully treated with adenosine. Both mothers and fetuses were monitored during treatment. Adenosine successfully converted the SVT to sinus rhythm, in all four patients. One patient was treated successfully twice, at 15 weeks and subsequently at 24 weeks. No complications occurred to either the mothers or the fetuses during the treatment. Five and ten minute APGAR scores at birth were greater than seven. Mothers and babies were followed from 1 month to 5 years after treatment and no contributory deleterious effects have been found. One patient was lost to follow-up.Conclusion: Our four patient cases, added to the limited published cases in the literature, support adenosine's safety and efficacy for the medical treatment of supraventricular tachycardia in the hemodynamically stable pregnant woman.

Journal Article↗
PubMed1998

Detecting and improving compliance. Is concordance the solution?

BACKGROUND: Despite the proven benefits of hypertension control, fewer than 50% of those treated for hypertension have their blood pressure adequately controlled. The major reason for this is poor compliance with treatment. OBJECTIVE: This article examines the extent of the problem, methods of detection and effective strategies in managing the problem of poor compliance with medical care with particular reference to hypertension. New ideas in the field are also discussed. DISCUSSION: Self-report is probably the best method of detection of poor compliance. Strategies of managing the problem are discussed.

Antihypertensive Agents↗
PubMed1994

Intraligamentary pregnancy.

Intraligamentary pregnancy, although rare, tests the physician's acumen in diagnostic and therapeutic skills. Two cases illustrating this entity are presented, the first involves an 18-week fetus, the second a partial hydatidiform mole. Although their presentation and pathogenesis may be indistinguishable, their clinical course and management is different. To the best of our knowledge, this is the first reported case of an intraligamentary pregnancy involving a partial hydatidiform mole.

Adult↗
PubMed1994

Endothelin-1 stimulates the in vitro release of neurohypophyseal hormones, but not corticotropin-releasing hormone, via ETA receptors.

The endothelins consist of a family of vasoconstrictor peptides originally isolated from endothelial tissue which are now known to be involved in neuroendocrine regulation. However, while there are data indicating the involvement of endothelins in the modulation of the hypothalamo-pituitary-adrenal (HPA) axis, the precise mechanisms involved have been unclear. We have therefore used a previously validated rat hypothalamic explant system in order to investigate the possible modulation of the neurohypophyseal hormones vasopressin and oxytocin, and corticotropin-releasing hormone (CRH), by endothelin-1 (ET-1) and endothelin-3 (ET-3). Following a period of stabilisation, the release of vasopressin, oxytocin and CRH remained approximately constant in successive 20-min incubations. Addition of ET-1 stimulated the release of vasopressin at a dose of 0.1 nmol/l (p < 0.05), and both vasopressin and oxytocin at 10 nmol/l (p < 0.01 and 0.05, respectively). The release of vasopressin and oxytocin induced by 10 nmol/l ET-1 were both totally blocked by co-incubation with either 1 or 10 mumol/l of the specific ETA receptor subtype antagonist cyclo (D-Trp-D-Asp-Pro-D-Val-Leu) (BQ-123). ET-1 had no effect on CRH release in the dose range of 0.1-1,000 nmol/l. In case any possible stimulation of CRH might be masked by simultaneous generation of nitric oxide (NO), an inhibitor of CRH secretion, addition of ET-1 was also carried out in the presence of the NO synthase inhibitor, L-NO-Arg: ET-1 was again without effect in this dose range.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Oxidoreductases↗
PubMed1994

Caudal regression syndrome: etiopathogenesis, prenatal diagnosis, and perinatal management.

Caudal regression syndrome represents a continuum of congenital malformations ranging from agenesis of the lumbosacral spine to the most severe cases of sirenomelia with lower extremities fusion and major visceral anomalies. The etiology of this syndrome is not well known. Maternal diabetes, genetic predisposition, and vascular hypoperfusion have been suggested as possible causative factors. The degree of associated anomalies usually parallels the severity of the primary defect. Ultrasonography is the diagnostic tool of choice revealing the absent distal vertebrae of the fetal spine. Amnioinfusion and magnetic resonance imaging (MRI) are of help in better evaluation of the fetal anatomy in cases with oligohydramnios. Perinatal management depends mainly on gestational age at diagnosis and severity of the lesion. It should include genetic counseling and serial sonography to assess interval growth and amniotic fluid volume. Surviving infants have usually a normal mental function and they require extensive urologic and orthopedic assistance. Their long-term morbidity consists mostly of neurogenic bladder dysfunction resulting in progressive renal damage and disabling neuromuscular deficits of the lower extremities. Neurosurgical and orthopedic intervention with physical rehabilitation is indicated to improve the quality of their lives.

Abnormalities, Multiple↗
PubMed1993

Nitric oxide modulates the release of vasopressin from rat hypothalamic explants.

The enzyme nitric oxide (NO) synthase is present in the paraventricular nucleus, while nitric oxide has recently been shown to inhibit the stimulated release of corticotrophin-releasing hormone (CRH) in vitro. Thus the possible role of NO in regulating, vasopressin (AVP), which also plays an important role in pituitary-adrenal activity, has been investigated. The effects were studied of the NO donors, L-arginine, syndnonimine-1 (SIN-1) and sodium nitroprusside, on both the basal and stimulated release of AVP, employing a previously validated system. Rat hypothalami were incubated in either medium alone or medium containing the test substances and hormone release was measured by RIA. The effect of L-arginine in the presence of the NO synthase inhibitor, L-NMMA, was also investigated. L-arginine reduced KCl-evoked AVP release; this effect was reversed by L-NMMA and reduced by the addition of ferrous human Hb. Similarly, SIN-1 and sodium nitroprusside attenuated KCl-evoked AVP release. L-arginine also reduced IL-1 beta-stimulated AVP release. NO appears to directly and specifically inhibit the stimulated release of AVP from rat hypothalamic explants in vitro, similar to its effects on CRH. These findings provide further evidence that NO may be involved in neuroendocrine regulation.

Amino Acid Oxidoreductases↗
PubMed1990

Perinatal implications of cocaine exposure.

Obstetric outcome was reviewed for 139 women who volunteered information on cocaine abuse during pregnancy past 20 weeks. Information on the duration of use during pregnancy was not accurate enough for documentation. In previous pregnancies, only 44.6% of the infants were live born, with spontaneous or therapeutic abortions in 41.1% and stillbirths accounting for 3.6%. In the current pregnancies, 91 patients (66.1%) were nonwhite, and multiple-drug usage was found in 92%, with intravenous cocaine use in 44.6% and freebasing in 31.7% as the main routes of administration. Syphilis or another infection, no prenatal care and poor weight gain (less than or equal to 19 lb) in pregnancy was present in one-third of the patients, while 38% did not know their gestational age. Precipitate labor was found in 63.9% and meconium-stained amniotic fluid in 20.5%. The mean birth weight of the infants was significantly lower than that of the general hospital population; low birth weight (less than 2,500 g) occurred in 36.2%, small size for gestational age in 32.4%, neurologic problems in 30.9% and syphilis in 15.4% of the infants. Congenital abnormalities, in 17.4%, seemed to be multifactorial. The consistent pattern of poor outcome in both the previous and present pregnancies reflects the life-style peculiar to cocaine abusers. Prospective studies are in progress to identify the true incidence of cocaine usage and to outline the counseling of childbearing women against cocaine use during pregnancy, emphasizing prevention since cures are not available.

Abnormalities, Drug-Induced↗
PubMed1989

Evaluation of surgical staples in cesarean section.

Experience with Lactomer absorbable surgical staples (Auto Suture Poly CS 57 disposable surgical stapler) in 62 cesarean sections was compared with an equal number of operations performed with standard techniques. The technique of application of the stapler evolved with experience. Countertraction to staplers with Allis' clamps prevented uterine V incisions. Operative time was longer for the stapled suture group for primary cesarean sections, but was unchanged for repeat procedures. Excellent hemostasis of the uterine incision was achieved even when varicose sinusoidal veins were present. Significant reductions of hemoglobin deficits from 2.16 to 1.31 gm/dl, postoperative anemia from 29% to 6.4%, and endometritis from 22.5% to 6.4% occurred respectively in nonstapled and stapled groups. A reduced hospital stay, shortened by 2.1 days, saved each patient +F42950. Blood loss estimates by surgeons or anesthetists were often at variance. Surgeons' acceptance of the procedure grew with experience. On the basis of these results, use of absorbable staples offers certain advantages in reducing blood loss, infection, and hospital stay in cesarean deliveries.

Adult↗