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Biomedical subjects

I Cohen

Publications and source records attributed to I Cohen.

At least 325 records · Page 18Linked to original sources
PubMed1985

Endocrinological evaluation in a case of XX male syndrome.

A case of a phenotype male with 44 XX karyotype is presented. Clinical, endocrinological and anatomical findings are recorded. Serum level of FSH was elevated, LH level was normal and testosterone level was low. A subnormal response by testicular Leydig cells to hCG was observed. A dexamethasone suppression test and an ACTH test were normal. A B scan ultrasonographic examination did not show female internal genitalia, nor a hyperplasia of adrenal tissue. A review is made of the literature with theories of etiology.

17-alpha-Hydroxyprogesterone↗
PubMed1985

Neonatal outcome of infants delivered at 26-28 weeks of gestation.

The delivery results of 42 infants born to 40 mothers at the gestational age of 26-28 weeks during a period of 5 years were analyzed. The study was evaluated in two periods of time: in the first period out of 15 infants born only 5 (33.3%) survived, while in the second period 21 (77.7%) out of 27 infants survived (p less than 0.01). 38 infants were transferred to a neonatal intensive care unit for premature infants. Only 41% of the infants transferred in the first period survived, as compared to 80.7% of those transferred during the second period (p less than 0.01). There was no significant difference in the mean birth weight at each gestational age between the survivors and those who subsequently died in both periods of the study. In the study groups, cesarean section rate rose from 13.3% in the first period to 44% in the second. Mode of delivery, regardless of the presenting part, did not seem to influence neonatal survival. Obstetrical management, including the performance of operative delivery for fetal indications and active neonatal resuscitation, seems to be reasonable for infants at the gestational age of 26 weeks or more.

Cesarean Section↗
PubMed1985

An unusual case of cervical pregnancy.

A very rare case of an unruptured cervical pregnancy, diagnosed by vaginal examination is described. An elective abdominal hysterectomy was performed. No complications related to this entity occurred during treatment. Clinical management and literature are discussed.

Adnexa Uteri↗
PubMed1985

Disulfide-linked and transglutaminase-catalyzed protein assemblies in platelets.

Energy depletion induces the formation of disulfide-linked and transglutaminase-catalyzed protein assemblies in platelets. The disulfide type polymers, formed following incubation at 37 degrees C in the absence of adenosine triphosphate (ATP)-generating precursors, are composed of cytoskeletal proteins and are associated with a decrease of reduced glutathione levels accompanying ATP depletion. The maintenance of ATP and reduced glutathione levels to, respectively, 34% and 47% of their original values is sufficient to prevent the formation of both polymer types. The transglutaminase-type cross-links are formed in the presence of calcium in either "energy-depleted" or thrombin stimulated platelets. 125I-surface-labeled membrane proteins, presumably transmembrane proteins, are incorporated into the transglutaminase-catalyzed cross-linked polymer of thrombin-stimulated platelets. Glycoproteins IIb and IIIa are not essential to the polymer formation, since thrombasthenic platelets treated with thrombin exhibit the same type of labeled polymer. The transglutaminase-catalyzed polymer formation following thrombin stimulation of platelets is inhibited by a calcium channel blocker, an intracellular calcium antagonist, as well as other inhibitors such as indomethacin, dibutyryl cyclic AMP, and prostaglandin E1. Although the evidence points to the formation of transglutaminase-catalyzed cross-linking in the cytoplasmic compartment, additional cross-linking of extruded components cannot be excluded.

Acyltransferases↗
PubMed1985

Clinical and laboratory investigation of the effects of epsilon-aminocaproic acid on hemostasis.

We previously reported that epsilon-aminocaproic acid (EACA) prolonged the bleeding time in patients with intracranial aneurysms when given in doses of 36 to 48 gm/day. We now show that doses of 24 gm/day also prolong the bleeding time, but only after 72 hours of continuous infusion. The effect on the bleeding time correlates with the duration of EACA therapy but not with the plasma level of the drug. Bleeding times return toward normal within 72 hours of discontinuing EACA infusions. The factors responsible for the bleeding time prolongation were investigated. In vitro, EACA inhibited adenosine diphosphate- and collagen-induced platelet aggregation and the release of platelet adenosine triphosphate and serotonin. It also prevented the adenosine diphosphate-stimulated binding of fibrinogen to intact as well as to chymotrypsin-treated platelets. However, platelets obtained from patients who had received EACA showed little functional impairment. This observation indicates that the focus of EACA activity in vivo is probably not the platelet per se, but the platelet-vessel wall interaction or a vascular component alone. EACA did not enhance prostacyclin production or release from cultured bovine endothelial cells. The fact that the effects of the drug on the bleeding time were related to the duration of EACA therapy suggests that an accumulation of the drug on the vessel wall may be required before alterations in hemostasis are observed. EACA in a daily dose of 24 gm significantly impaired fibrinolysis, but supranormal levels of fibrinolytic activity were observed within 72 hours of stopping the drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Aminocaproates↗
PubMed1985

Single-dose mezlocillin prophylaxis in emergency cesarean section.

A single 5-gm dose of mezlocillin or a placebo was administered intravenously 30 minutes before surgery to patients undergoing emergency cesarean section. The assignment of drug or placebo was randomized. Postoperative morbidity occurred in 62.5% of patients receiving placebo and in 18.4% of those receiving mezlocillin (P less than 0.001). The incidences of febrile morbidity, endometritis, and urinary tract infection were significantly lower in the group given mezlocillin. Other benefits of antibiotic prophylaxis included a shorter hospital stay and no serious infections in the group given mezlocillin.

Adult↗
PubMed1984

Excitability and depolarization-release characteristics of excitatory nerve terminals in a tail muscle of spiny lobster.

In the deep abdominal L1-extensor muscle of the spiny lobster (Panulirus penicillatus) quantal excitatory postsynaptic currents (EPSCs) were recorded through macro-patch-clamp electrodes. Release of transmitter quanta from terminals was also elicited by depolarizing current pulses given through the recording electrode. The majority of terminals were excitable: on increasing the depolarization pulses, release was triggered at a threshold in an all-or-nothing manner. If excitation was blocked by tetrodotoxin (TTX), release was graded with depolarization reaching the amplitude of the all-or-nothing response at pulse amplitudes several times higher than the former threshold level. Some inexcitable terminals were also found: in these, release was graded for increasing depolarization pulses, and TTX did not alter the depolarization-release relation. Among the other types of terminals studied with the same technique, the proportion of excitable terminals in this lobster tail muscle is higher than in the crayfish opener and lower than in the frog's cutaneous pectoris muscle. The contribution of the increase in intraterminal Ca concentration to the control of release was estimated using facilitation of a test EPSC as an indicator of Ca inflow during a preceding depolarization pulse. This facilitation was found to have a maximum at a certain pulse amplitude, PF, and to decline for larger depolarizations. Release, however, rose considerably for depolarizations larger than those effected at PF. It is concluded that, like in crayfish and frog motor terminals, release is controlled directly by depolarization in addition to the control by Ca-inflow.

Action Potentials↗
PubMed1984

Papillary adenofibroma of the endometrium: case report and review of the literature.

A case of papillary adenofibroma of the endometrium is reported in a 78-year-old parous woman. Diagnosis was made by curettage. The patient was treated by total abdominal hysterectomy with bilateral salpingo-oophorectomy. This is the eighth case known in the literature. Clinical and pathological aspects of this relatively new pathological entity are reviewed.

Adenofibroma↗
PubMed1984

Saturation of the internal sodium site of the sodium pump can distort estimates of potassium affinity.

The Na+/K+ exchange pump in cardiac Purkinje strands has been well studied with the voltage clamp and Na+-selective microelectrodes. Models describing the observed results suggest that the pump rate can be considered proportional to [Na+]i over the range examined and depends on external [K+] in accordance with Michaelis-Menten kinetics. Estimates of the external [K+] that achieves a half-maximal pump rate (Km) range from 0.9 to 6.3 mM depending on the preparation and method of estimation. Here we show that much of the variability in the estimates of the Km can be eliminated when saturation of the internal Na+ pump site is taken into account. If the half-activation concentration for saturation of this Na+ site is sufficiently high (greater than 20 mM), removal of intracellular Na+ in response to a Na+ load will approximate first-order kinetics. Under these conditions however, Na+ saturation will nevertheless cause large systematic errors in estimates of the K+ dependence of pump activity.

Animals↗
PubMed1984

Neonatal glucocorticoid administration: effect on the diurnal rhythm of serum concentrations of corticosterone, progesterone and LH, and the response to pregnant mare serum gonadotrophin in immature female rats.

The effects of neonatal cortisol acetate administration on diurnal changes in serum corticosterone, progesterone and LH and on the response to pregnant mare serum gonadotrophin (PMSG) were examined in immature female rats. Neonatal cortisol treatment (250 micrograms/rat) abolished the diurnal rhythm of serum progesterone in rats at 27-29 days of age, and lowered overall the serum progesterone response to PMSG. Neonatal cortisol also reduced the number of animals ovulating on day 28 after PMSG injection 48 h earlier. This dosage of cortisol did not alter the diurnal rhythm of serum corticosterone in these animals. Serum LH concentrations in control rats at 27-29 days of age did not differ between 09.00 and 18.00 h, and prior treatment with cortisol acetate did not significantly influence serum concentrations of this hormone. Our data suggest that ovarian production of progesterone contributes significantly to diurnal fluctuations of this steroid in the circulation of immature rats. Perinatal exposure to cortisol acetate abolishes the diurnal rhythm of serum progesterone and impairs the ovarian response of the immature female rat to PMSG. The mechanism(s) by which cortisol acetate alters these processes remains to be determined.

Animals↗
PubMed1984

Strengthening of synaptic contacts of an excitatory axon on elimination of a second excitatory axon innervating the same target.

In the deep abdominal extensor muscles of spiny lobsters (Panulirus-pennicillatus), the common excitor axon of segment II was eliminated by intracellular injection of pronase. At 1 to 23 days after the operation, the quantal content of excitatory postsynaptic currents (EPSCs), elicited by stimulation of the specific excitor of the L1 muscle, was determined in a specific area of the L1 muscle, both in the operated and in the contralateral control side. The EPSCs in the operated muscles had about a 5 times higher quantal content compared to those in the controls, the change developing within 1 to 2 days after operation. In camera lucida drawings of preparations stained with methylene blue, increased branching of the remaining excitatory axon was obvious at more than 4 days after the operation. To investigate the possibility of contribution of central mechanisms (Rotshenker, S. (1979) J. Physiol. (Lond.) 292: 535-547). to this effect, the bundle of five axons to the deep abdominal extensors of segment II was cut immediately after injection of pronase into the common excitor axon. This caused a reduction of the quantal content of EPSCs and shrinking of the field of innervation in the operated L1 muscle as compared to the control. Therefore, axonal continuity or central connections seem to be necessary for the development of an increased innervation by the specific excitor to L1 after eliminating the common excitor axon. Possible postsynaptic effects of the elimination of the common excitor axon were controlled by recording synaptic single channel currents elicited by the excitatory transmitter glutamate, using the patch clamp method. These single current events did not show appreciable changes in operated L1 muscles. Therefore, the presynaptic strengthening effect on the nerve terminals of the specific L1 excitor is predominant after elimination of the common excitor axon.

Animals↗