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Biomedical subjects

M Katz

Publications and source records attributed to M Katz.

At least 397 records · Page 22Linked to original sources
PubMed1984

Cardiovascular consequences of beta-agonist tocolysis: an echocardiographic study.

M-mode echocardiography was performed before and during intravenous beta-adrenergic agonist tocolysis in 13 patients with preterm labor. There was a significant increase in heart rate, fractional shortening, and calculated cardiac output. There was also a significant decrease in both end-systolic and end-diastolic left ventricular dimensions, which resolved in 24 to 36 hours. There were, however, no changes in left atrial dimensions. The data derived from this study suggest that the pulmonary edema occasionally complicating beta-adrenergic agonist tocolysis is not the result of systolic cardiac dysfunction.

Adrenergic beta-Agonists↗
PubMed1984

Muscle ischemia and hypothermia: a bioenergetic study using 31phosphorus nuclear magnetic resonance spectroscopy.

UNLABELLED: Following traumatic limb amputation it is common clinical practice to maintain the ischemic tissues in a hypothermic state until surgical reimplantation. Of all extremity tissues, muscle is the most sensitive to ischemia; it is therefore imperative that reperfusion be established before diffuse muscle necrosis. Although it has been shown both clinically and experimentally that hypothermia prolongs the viability of ischemic skeletal muscle, the presumed mechanism by which this occurs has not been confirmed at the cellular level. This study was undertaken to quantify the effect of conventional iced-saline hypothermia on anaerobic cell metabolism and high-energy phosphate depletion in traumatically devascularized muscle. METHODS: Phosphorus nuclear magnetic resonance spectroscopy (31P NMR) was employed to noninvasively monitor cellular phosphocreatine (PCr), ATP, and intracellular pH over time in ischemic cat hindlimb muscle under room temperature (22 degrees C) and 1 degree C hypothermic conditions. RESULTS: Muscular PCr depletion was significantly retarded by tissue hypothermia but the rate of ATP depletion was not. A progressive, severe cellular acidosis was observed in the room-temperature muscle. Iced tissue cooling produced a dramatic initial rise in cell pH which significantly reduced the absolute degree of subsequent acidotic changes. SIGNIFICANCE: These findings question our understanding of hypothermic tissue preservation, which has generally been assumed to work on the basis of decreased tissue metabolism, thus conserving critical cellular ATP levels. The empirical benefit derived by cooling muscle in an iced medium may actually be related to the cellular alkalinization produced by tissue cooling, as this significantly mitigates the profound acidosis that would otherwise occur.

Adenosine Triphosphate↗
PubMed1984

Characteristics of uterine activity during the breast stimulation stress test.

Characteristics of uterine activity produced by nipple stimulation were studied in 185 consecutive breast stimulation stress tests. Adequate contractions were produced in 95.6% of tests. Exaggerated uterine response (contractions occurring more than once every two minutes or lasting more than 90 seconds) was present in 45.5% of the patients. Twenty-one percent of the patients with such uterine activity also had a fetal heart rate (FHR) deceleration (hyperstimulation breast stimulation stress test), without adverse fetal outcome. The time in minutes from start of nipple stimulation to the first contraction (stimulation contraction interval) was recorded for each patient. Significant difference was not observed in the stimulation contraction interval distribution between the groups with and without exaggerated uterine activity. The authors conclude that there is a relatively high incidence of exaggerated uterine activity response to the breast stimulation stress test and that close surveillance of mother and fetus is warranted during antepartum nipple stimulation.

Apgar Score↗
PubMed1984

Lymphography and percutaneous fine needle node aspiration biopsy in the staging of bladder carcinoma.

Forty-two patients with infiltrating bladder tumor were submitted to pedal lymphography with percutaneous fine needle node aspiration biopsy on an out patient basis. Of 41 evaluable patients, 59% had a positive lymphangiogram. Adequate material was obtained in 81% of the patients. Of 12 patients with a normal lymphography, none had a positive aspiration whereas 40% of the positive lymphangiograms correlated with a positive aspiration. The high rate of positive lymphangiogram negative aspirate is attributed to inflammatory changes due to previous TUR of the tumor. Twenty-one patients were submitted to radical cystectomy: 12 negative aspirations correlated with 11 negative lymphadenectomies, and 4 positive aspirations with 4 positive lymphadenectomies. There was no mortality and only mild morbidity in this series. Lymphography with fine needle percutaneous node aspiration biopsy has a role in the pre-operative staging of bladder carcinoma. Positive pelvic wall lymph nodes upgrade bladder carcinoma from a local to a systemic disease that is no longer amenable to any form of local treatment. Nodal assessment is therefore critical to treatment planning in order to spare the N+ patients unnecessary radical surgery. Pelvic lymph nodes have been evaluated, in the past, radiologically by bipedal lymphography or C.A.T. scanning. The high false positive and negative rates of these procedures (Benson et al., 1981; Boccon-Gibod et al., 1982) preclude their routine use (Correa 1982; Walsh et al., 1980).(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy, Needle↗
PubMed1984

Role of plasmapheresis in preparing myasthenic patients for thymectomy: initial results.

Between 1976 and 1981, one of the authors operated on 16 patients for myasthenia gravis. Plasmapheresis was carried out preoperatively on seven patients, while nine patients were operated upon without previous plasmapheresis. The seven patients who underwent plasmapheresis had a smooth course pre- and postoperatively. In the other group, there were two postoperative myasthenic complications. Both patients improved with medication and plasmapheresis. Also, the degree of myasthenia gravis was slightly more severe in this group. From their experience, the authors conclude that plasmapheresis is a worthwhile and safe adjuvant in the preparation of myasthenic patients for thymectomy, especially those in Osserman class IV.

Adolescent↗
PubMed1983

Inhibitory effect of 7,8-benzoflavone on DMBA- and BaP-induced bone marrow micronuclei in mouse.

Frequencies of micronucleated polychromatic erythrocytes (PCE) were analyzed in bone-marrow cells of mice injected with 7,12-dimethylbenz[a]anthracene (DMBA), benzo[a]pyrene (BaP), 7,8-benzoflavone (alpha-naphthoflavone) and the combination of either 7,8-benzoflavone and DMBA or 7,8-benzoflavone and BaP. 7,8-Benzoflavone was injected 48 and 24 h before injecting mice either with DMBA or BaP. Bone-marrow samples were collected at 24, 48, 72 and 96 h. The observed maximum mean number of micronucleated PCE per 500 PCE was 8.6 at 48 h with DMBA and 11.6 at 72 h with BaP. 7,8-Benzoflavone reduced the number of micronucleated PCE in the above treatments with DMBA by 90% and in the case of BaP by 75%. In other words, 7,8-benzoflavone acted as a potent inhibitor in preventing chromosomal breaks caused by DMBA or BaP.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1983

The significance of single sporadic deceleration during a nonstress test.

The significance of single sporadic deceleration occurring during antepartum fetal heart rate monitoring was assessed. Single sporadic deceleration was defined as a drop of fetal heart rate of at least 40 bpm below baseline lasting for at least 2 min. During the year 1980, 7202 nonstress tests (NST) were performed in pregnant patients, with gestational ages ranging from 32-42 wk. Among these, 62 cases of single sporadic deceleration were observed. In 48 of these cases the single sporadic deceleration was followed by a normal reactive NST. In 14 patients NST following the single sporadic deceleration was non-reactive. In those cases oxytocin challenge test (OCT) was performed and was negative in 10 and positive in 4 cases. In the latter 4 patients labor was induced and all required cesarean section because of severe fetal distress. The remaining 58 women were followed up at the High-Risk Pregnancy Unit until spontaneous labor began, their deliveries were monitored throughout. In 8 cases out of the 58, fetal distress was observed during labor and in 4 of them cesarean section was required. The occurrence of single sporadic deceleration at gestational ages 32-42 wk is not an alarming sign providing the NST and/or O.C.T. are normal. However, the incidence of fetal distress during labor is significantly higher in fetuses with single sporadic deceleration as compared to the normal parturient population.

Female↗
PubMed1983

Caffeic acid as an inhibitor of DMBA-induced chromosomal breakage in mice assessed by bone-marrow micronucleus test.

Female mice of hybrid strain B6C3F1, 8-10 weeks old, were fed on powdered food with or without 2% caffeic acid. After one week on these diets, some of each group of mice were injected i.p., with 7,12-dimethyl benz[a]anthracene (25 mg/kg) dissolved in dimethyl disulfoxide. In the course of separate experiments, bone-marrow samples were taken at various intervals after injection for analysis in the micronucleus assay. From each mouse 500 polychromatic erythrocytes were scored to determine the frequency with micronuclei. At the time at which the maximum response was observed, which differed between experiments, the frequency of micronuclei induced by DMBA was reduced by 50% by the presence of caffeic acid. Caffeic acid (3,4-dihydroxy cinnamic acid) is widely distributed in plant materials in both free and combined forms and, as such, is a component of the human diet. Our results suggest that caffeic acid provides significant protection against the genotoxicity of DMBA.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1983

Distortion by ophthalmic lenses calculated at the farpoint sphere.

Distortion by ophthalmic lenses has generally been calculated with respect to an ideal flat image surface. This results in improper distortion values as the ideal image surface for the mobile eye is the farpoint sphere. Results of distortion calculations for lenses ranging from +20 to -24.65 D are given for point focal lenses (corrected for oblique astigmatism), Percival lenses (designed to place the circle of least confusion on the farpoint sphere), minimum astigmatism and minimum distortion lens forms. Distortion of point focal Ostwalt lenses of powers +6.60 to -24.65 D range from 4.45 to -28.31% when computed at the flat image surface. Referred to the farpoint sphere the corresponding distortion values are +0.85 to -13.54%. Similarly, the distortion of the minimum astigmatic forms of lenses ranging in power from +20 to +7 D are +27.31 to 4.64% at the flat image surface but decreased to +16.38 to 0.84%, respectively, at the farpoint sphere. If the rotations of the unaided ametropic eye that are required to fixate two points in the field are compared with the necessary rotations with a spectacle correction (+20 to -24 D), it is found that the corrected eye rotation errors at the flat image surface range from 14.87 to -4.53%, but drop to +0.87 to -1.88% when referred to the farpoint sphere. It is concluded that distortion at the farpoint sphere is a more valid measure of distortion for the mobile eye than the classical measurement of distortion. This has implications for the study of space perception through lenses.

Eyeglasses↗
PubMed1983

Clinical significance of sinusoidal fetal heart rate pattern.

Sinusoidal fetal heart rate pattern has been regarded as a sign of fetal jeopardy and 92 instances of this pattern were analysed. The morphologically different major and minor sinusoidal patterns were assessed with regard to their clinical significance as predictors of fetal compromise. There were 83 instances of minor sinusoidal pattern (amplitude of oscillation less than 25 beats/min) with only one antepartum fetal death. Major sinusoidal pattern (amplitude of oscillation greater than 25 beats/min) was diagnosed in nine patients and in six of them the fetus died before, during or after delivery. It is concluded that patients with minor sinusoidal heart rate patterns may be managed expectantly, whereas on the rare occasion when a major sinusoidal pattern is seen expeditious delivery is justified.

Apgar Score↗
PubMed1983

The recurrent cerebellar astrocytoma.

5 children with six recurrences of cerebellar astrocytoma are reviewed. The clinical course is correlated with the grading system of Gilles for posterior fossa gliomas. Changes in the Gilles classification were found in some tumors at the time of reoperation. The delayed occurrence of hydrocephalus signified recurrence of tumor. Regardless of the apparent histologic benignity of the tumors, cerebellar astrocytomas have the capacity to regrow even after apparent total removal. Routine follow-up CT scans should be performed to detect asymptomatic recurrences.

Adolescent↗