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Biomedical subjects

A Weller

Publications and source records attributed to A Weller.

At least 37 records · Page 2Linked to original sources
PubMed2001

Release of endogenous cholecystokinin in response to gastric preloads in rats on postnatal days 9--12.

Release of endogenous cholecystokinin (CCK) from the small intestine by gastric loads was investigated in rats on postnatal days 9--12 (P9--P12). After 5--6 h of deprivation, pups received 5% b.wt. loads of water, 0.9% NaCl, 20% glucose, 20% maltose, 200 mg soybean trypsin inhibitor (SBTI) in 0.9% saline or sham load. Plasma was collected 15 min after the loads, and the concentration of bioactive CCK was measured by a specific and sensitive bioassay. Loads of SBTI and water significantly increased plasma CCK compared to sham loads, but loads of saline, glucose, and maltose did not. The efficacy of the water load was not demonstrated in adult rats. The results suggest that the previously reported reduction of intake during independent ingestion by hypertonic preloads of glucose and maltose was not mediated by the release of CCK sufficient to be detected in the plasma under these conditions.

Animals↗
PubMed2001

Hypertonic glucose preloads act preabsorptively to decrease intake in rats on postnatal day 18.

To determine if preloads of glucose act preabsorptively or postabsorptively to inhibit intake, 18-day-old rat pups were deprived for 24 h and then provided with sweet milk during a 30-min independent ingestion test. Five minutes before the test, gastric preloads (5% body weight, BW) or intraperitoneal injections (4 ml/kg BW) of isotonic, hypotonic, and hypertonic solutions of glucose or 2-deoxy-D-glucose (2-DG) were administered. There were two major results: First, preloads of 20% glucose decreased intake much more than intraperitoneal injections of 20% glucose. Second, a preload of 20% 2-DG, which decreases, rather than increases glucose utilization, was as effective as a preload of 20% glucose in decreasing intake. These results are consistent with a preabsorptive osmotic mechanism, but not with a postabsorptive metabolic mechanism, for mediating most, if not all, of the inhibition of intake 5 min after preloads of 20% glucose in rats on postnatal day 18 (P18).

Animals↗
PubMed2001

Examining the role of cholecystokinin in appetitive learning in the infant rat.

The role of Cholecystokinin (CCK), a gut hormone and neuropeptide, in early learning was examined. Pairing a novel odor (presented away from the nest) with exogenously administered CCK (0.25 & 0.5 microg/kg IP) has been shown to produce a conditioned-odor preference in infant rats (Weller, A.; Blass, E.M. Behav. Neurosci. 104:199-206; 1990). This suggests that CCK can act as a positive unconditioned stimulus (UCS). In the present study the possibility that CCK mediates learning was examined in 12-day-old rats, using rewards that represent aspects of the dam and the nest. In Experiments 1 and 2, pups received the selective CCK1 receptor antagonist devazepide (600 microg/kg), the selective CCK2 receptor antagonist L365,260 (600 microg/kg), or vehicle. In a series of training trials, choosing a particular floor texture was rewarded by 20 sec. on a rug texture (experiment 1) or with maternal (feces) odor (experiment 2). In experiment 3, after administering devazepide (0, 600, or 1000 microg/kg) a novel odor was paired once with reunion of the pup with its dam. The dependent measure in all studies was the pup's relative preference toward the (tactile or olfactory) conditioned stimulus (CS), determined in preference tests. Conditioned preferences were evident in all experiments. The CCK receptor antagonists did not increase conditioned preference levels. L365, 260 (experiment 2) and devazepide (experiment 1) clearly blocked the appearance of the conditioned effect in one of the experiments. In addition, devazepide treatment eliminated the conditioned effect in the two other experiments, by increasing preference levels in the control groups. In summary, the results suggest that endogenous CCK mediates some aspects of the infant's acquisition of new associations. The role of the two receptor-subtypes appears to be different, depending on the context and the nature of the rewarding stimulus.

Animals↗
PubMed2001

The brain decade in debate: VIII. Peptide hormones and behavior: cholecystokinin and prolactin.

This article is a transcription of an electronic symposium held on November 28, 2000 in which active researchers were invited by the Brazilian Society of Neuroscience and Behavior (SBNeC) to discuss the advances of the last decade in the peptide field with particular focus on central actions of prolactin and cholecystokinin. The comments in this symposium reflect the diversity of prolactin and cholecystokinin research and demonstrate how the field has matured. Since both peptides play a role in reproductive behaviors, particularly mother-infant interactions, this was the starting point of the discussion. Recent findings on the role of the receptor subtypes as well as interaction with other peptides in this context were also discussed. Another issue discussed was the possible role of these peptides in dopamine-mediated rewarding systems. Both prolactin and cholecystokinin are involved in mechanisms controlling food intake and somatic pain thresholds. The role of peripheral inputs through vagal afferents modulating behavior was stressed. The advent of knockout animals as potential generators of new knowledge in this field was also addressed. Finally, interactions with other neuropeptides and investigation of the role of these peptides in other fields such as immunology were mentioned. Knowledge about the central functions of prolactin and cholecystokinin has shown important advances. The role of these peptides in neurological and psychiatric syndromes such as anorexia, drug abuse and physiological disturbances that lead to a compromised maternal behavior seems relevant.

Brain↗
PubMed2000

Fibrinogen Longmont: a dysfibrinogenemia that causes prolonged clot-based test results only when using an optical detection method.

A new fibrinogen variant was discovered as a result of discrepancies found in routine laboratory screening. The patient, a healthy 37-year-old woman, had a mild bleeding history. Initial coagulation studies on the patient revealed a prolonged prothrombin time (PT) and a normal activated partial thromboplastin time (APTT). Further investigation on the patient and her mother demonstrated both had a PT with no end point using an optical detection method (ACL3000+) and a normal PT using an electromechanical detection method (ST4 Clot Detection System). The APTT for both the patient and her mother were essentially normal with both optical and mechanical detection methods. The patient and her mother also had markedly prolonged thrombin time and reptilase time results on the ACL3000+, but they were normal on the ST4. Coagulation test results on the patient's father were all normal. We believe the fibrinogen defect in this family may affect fibrin polymerization only enough to effect light scatter interpretation, while there is enough polymerization to increase plasma viscosity and yield an end point using an electromechanical analyzer. This report should alert pathologists and clinicians to possible discrepancies between mechanical and spectrophotometric clot testing methods.

Adult↗
PubMed2000

[Lens subluxation and glaucoma: indications and hazards of cataract surgery].

BACKGROUND: Iridodonesis is the clinical sign of lens subluxation. Acute glaucoma caused by a ciliolenticular block may develop. YAG iridotomy or peripheral iridectomy are rarely effective in controlling intraocular pressure. The results of phacoemulsification and posterior lens implantation for subluxated lens and glaucoma are reported. PATIENTS AND METHODS: Seven patients aged 69+/-9.5 years were followed up. All 10 eyes with subluxated lens and glaucoma had phacoemulsification and posterior chamber lens implantation. Two different groups relating to axial length could be analyzed. Intraoperative findings and postoperative glaucoma situation are reported. RESULTS: Six eyes had average axial length of 21.5+/-0.17 mm and previous acute glaucoma. Five of these eyes had therapeutic YAG iridotomy and one, peripheral iridectomy. All eyes had dysregulated glaucoma despite antiglaucomatous medications. After cataract surgery five of six eyes had regular intraocular pressure without any medication. Four eyes had average axial length of 24. 4+/-1.1 mm and chronic glaucoma. After complicated phacoemulsification three of these eyes had regular intraocular pressure with antiglaucomatous medication, one eye without. CONCLUSIONS: For short eyes with subluxated lens and preceding acute glaucoma, cataract surgery with posterior chamber lens implantation is an effective therapeutic procedure for IOP regulation. For chronic glaucoma with subluxated lens, conventional or surgical approach to glaucoma remains dominant.

Aged↗
PubMed2000

[Sponge anesthesia with intraocular lidocaine application in cataract surgery].

BACKGROUND: For cataract surgery in this country retro- and peribulbar anesthesia is the standard method. It totally stops eye movement as well as sensitivity to pain. Especially peribulbar anesthesia is known as a procedure with minimal complications, but the potential risks can be severe. In the past sponge anesthesia could not be used on patients with difficult cataract surgery due to the insufficient anesthetic effect. A modified anesthetic method is demonstrated for complicated cataract surgery. PATIENTS AND METHODS: In 281 non-selected, successive phacoemulsifications, all performed by the same surgeon, we applied sponge anesthesia and 1.5 mg midazolam as premedication. Only in cases of moderate and severe sensitivity was 1% 0.15 ml lidocaine applied intraocularly. The intensity of sensitivity was graded as 1 for low, 2 moderate, and 3 severe. RESULTS: Ninety eyes had complicated cataract surgery. Of the patients, 84.3% felt no pain during surgery; 11.4% were part of group 2 (moderate). Ten of 12 patients who had stated moderate sensitivity at first were free of pain after intraocular application of lidocaine, while the other 2 patients only felt minor sensitivity. CONCLUSION: The anesthetic procedure we present offers a safe alternative method to surgeons who are able to do surgical procedures on a mobile eye.

Aged↗
PubMed2000

The prothrombin Denver patient has two different prothrombin point mutations resulting in Glu-300-->Lys and Glu-309-->Lys substitutions.

Dysprothrombinaemia is a rare, congenital cause of bleeding. Fewer than 25 families who express a functional prothrombin (factor II) defect have been reported. The original patient with prothrombin Denver had a severe haemophilia-like bleeding disorder treated with weekly prophylactic factor replacement. Analysis of factor II activity and antigen in the patient showed a factor II activity of 5 units/dl and factor II antigen of 21 units/dl. Genomic DNA from the patient, mother and brother was obtained from peripheral blood white cells. Oligonucleotides were constructed, and prothrombin exons were amplified via polymerase chain reaction (PCR). The entire sequence of the thrombin portion of the molecule (exons VIII-XIV) and that of exons I-II and IV-VII was determined. This moderately severe dysprothrombinaemia was found to be associated with compound heterozygosity for two different Glu-->Lys point mutations, at amino acid positions 300 and 309. Assays of plasma from the prothrombin Denver proband suggested that the functional defect was in the activation of zymogen to enzyme.

Adolescent↗
PubMed2000

Ontogeny of hypertonic preabsorptive inhibitory control of intake in neonatal rats.

The ontogenetic development of postingestive inhibitory control of ingestion by the osmotic load of a preload was examined in rats. On postnatal days 6 (P6) and 12 (P12), pups were deprived for either 6 or 24 h. Gastric preloads (5% body wt) of water, mannitol (a sugar alcohol that is not absorbed) in six concentrations [from 0.125 M (hypotonic) to 1.0 M (hypertonic)], or sham preloads were administered 5 min before a 30-min intake test. Compared with sham treatment, isotonic mannitol (0.25 M), a probe of volumetric control, significantly reduced intake on P12, but not on P6. Compared with isotonic mannitol, the three highest hypertonic concentrations (0.5, 0.66, and 1.0 M) significantly decreased intake on P12, at both levels of deprivation. On P6, 0.66 and 1.0 M mannitol reduced intake after 24 h, but not after 6 h, of deprivation. Thus, on P6, the hypertonic control was detectable only after prolonged deprivation and the volumetric control was not present. On P12, both controls were observed and the hypertonic control was more potent than on P6.

Absorption↗
PubMed2000

Misuse of anticholinergic drugs by people with serious mental illness.

This study assessed misuse of anticholinergic drugs in a population of 50 patients with serious mental illness who were assertively managed by a community-based outreach team in Sydney, Australia. One-third of the subjects reported having misused anticholinergics over the previous month. All anticholinergics were misused, and trihexyphenidyl (benzhexol) was misused most frequently. Most subjects misused at least one other drug as well. On direct questioning, the reason given most frequently was "to get high"; on indirect questioning, reasons were related more to peer participation and feelings of futility. Marginalized patients living in the community are vulnerable to the misuse of anticholinergic drugs.

Adult↗
PubMed2000

A cholecystokinin receptor antagonist blocks milk-induced but not maternal-contact-induced decrease of ultrasonic vocalization in rat pups.

The role of cholecystokinin (CCK) in reducing separation-induced ultrasonic vocalization (USV) was examined by peripheral administration (of the selective CCK(A) receptor antagonist devazepide to 10-11-day-old rats. Pups placed alone for 2 min emitted a mean of 55.1 USV/min. When placed on a paper towel wet with warm, sweet milk, USV rate decreased to 23.2/min for the following 8 min. Devazepide (150-600 microg/kg IP) prevented this USV reduction, but did not increase feeding. In contrast, USV reduction produced by contact with the anesthetized dam was not affected by devazepide. Similarly, the opiate antagonist naltrexone (0.5 and 1.0 mg/kg) has been shown to block morphine-induced USV decrease in pups away from the dam, but was ineffective when USV reduction was induced by the presence of the dam (Blass et al., 1990; Carden & Hofer, 1990). The current findings suggest that CCK's role is specific, in that it mediates milk- but not dam-induced quieting of USV. The results, however, are not incompatible with the possibility that CCK and opioids are part of multiple, redundant pathways that mediate the quieting of USV by the dam.

Animals↗
PubMed1999

[Vis-à-tergo. Uveal effusion and expulsive hemorrhage in cataract surgery].

BACKGROUND: Since introduction of the self-sealing incision for cataract surgery it has been possible to avoid serious complications due to an acute rise in intraocular pressure. Chorioidal effusion (CE) and expulsive hemorrhage (EH) should be determined and treated differently. PATIENTS AND METHODS: The incidence of vis-à-tergo in our patients was 1.7%. CE was ascertained in 0.1%; in one case, the operation had to be interrupted. EH occurred in one patient (0.03%) in the last 3,000 cataract operations. Differential diagnoses were made by ultrasonic examination. RESULTS: Operations in CE cases were completed without further complications. However, in one case the operation was interrupted and the procedure was completed on the following day. A 63-year-old woman with EH had a massive rise in intraocular pressure directly after lens implantation with a peripheral capsular rupture. Postoperatively, a chorioidal hemorrhage in two quadrants, including the macula, was found. One week after surgery a posterior sclerotomy was performed with simultaneous infusion into the anterior chamber with BSS. The nearly complete chorioidal reattachment was achieved after drainage of the liquified blood. Visual acuity has improved to 0.5. CONCLUSION: Vis-à-tergo in modern cataract surgery only rarely results in an ES or EH. Also, in an EH there is an incomplete form. After an adequate therapeutic procedure good visual function can be expected.

Cataract Extraction↗
PubMed1999

Menstrual synchrony in a sample of working women.

Menstrual synchrony has been typically studied among women who live together: dormitory roommates or family members sharing a bedroom or living in the same house. The current study examined menstrual synchrony in 51 pairs of women working together under conditions optimally conducive to synchrony. They had been together for at least 1 year, shared a relatively small office, worked there all day full time and contact with other people during the day was minimal. Prospective records of three menstrual dates showed a significant degree of synchrony for each of the 3 months. Menstrual onsets of close friends tended to occur on the average within 3.5-4.3 days of each other while onsets of co-workers who were not close friends were significantly more broadly ranged (7.7-9.0 days of each other). This is the first unequivocal demonstration of menstrual synchrony outside of the household.

Adolescent↗
PubMed1999

Ethyl-nitrosourea transformed astrocytes exhibit mitochondrial membrane hyperpolarization and constrained apoptosis.

Recent studies have shown the mitochondria and mitochondrial DNA are altered in gliomas, studied either as primary tissues or in culture. Few studies have been performed which evaluate the mitochondria during the development of glial malignancy. We used an ethyl-nitrosourea (ENU) in vitro model to assess the changes in mitochondrial parameters with progression to astrocyte transformation. When compared to the untreated control cells mitochondrial mass of the ENU treated cells significantly decreased ontologically early with concurrent increase in mitochondrial membrane potential, resulting in hyperpolarization of the mitochondrial membrane. At successive divisions, the degree of spontaneous apoptosis during astrocyte transformation was significantly diminished in the ENU treated cells. With 24 h pre- and co-treatment of ENU cells with citrate, an allosteric inhibitor of phosphofructokinase, the astrocytes still became immortal, but did not manifest any of the mitochondrial changes nor acquire the transformed properties of the ENU treated cells without the inhibition. Indeed, the degree of apoptosis noted in these dually treated cells was increased, associated with a loss of anchorage independence and low density growth. Transformed subclones exposed to citrate after the development of malignant properties also exhibited increased apoptosis, and did not form colonies in low density plating conditions. These results suggest that the development of transformed properties in an ENU model is associated with marked hyperpolarization of mitochondrial membrane potential and diminished spontaneous apoptosis. Exposure to citrate attenuated these mitochondrial changes and in vitro growth properties, with increases in apoptosis. The development of transformed astrocytes involve constraints on apoptosis related to alterations in mitochondrial membrane potential and mass.

Journal Article↗
PubMed1999

Human menstrual synchrony in families and among close friends: examining the importance of mutual exposure.

Human menstrual synchrony was examined in a sample of 73 urban households with a relatively high degree of mutual contact and interaction but less than that of a previously studied, possibly unique sample of Bedouin families with an extremely high degree of contact, interaction, and sexual segregation (A. Weller & Weller, 1997). In addition, for the first time, menstrual synchrony was studied among best friends who did not live together and among sisters who did versus did not share a bedroom. A very high degree of synchrony was found among families (51%) and among sisters (51%), and a relatively high degree of synchrony was found among close friends (30%). The results suggest that synchrony can be attained without sleeping in the same bedroom or even in the same house. The findings also suggest that an effective range of mutual exposure is an attribute of human menstrual synchrony; below or above this range, the phenomenon may not occur.

Adolescent↗
PubMed1999

Treatment of acute graft-versus-host disease with PUVA (psoralen and ultraviolet irradiation): results of a pilot study.

Acute graft-versus-host disease (aGVHD) is a frequent and major complication after allogeneic stem cell transplantation. For many years psoralen and ultraviolet (UV)-A light have been used in the treatment of chronic cutaneous graft-versus-host disease, but few patients have received PUVA therapy for aGVHD. We assessed 20 patients who received PUVA therapy for acute cutaneous GVHD (grade 2-4). Seven patients showed additional organ manifestations (liver, gut). To better quantify the cutaneous lesions, a new scoring system was introduced: intensity of erythema (0-3) x %body surface + size of bullae (4-5) x %body surface affected. All patients received prednisolone and PUVA for treatment of aGVHD. Fifteen patients (75%), 12 with manifestations restricted to the skin, responded by score classification (average time to a 50% score reduction: 39 days) and reduction of the dosage of prednisolone (average time to a 50% prednisolone reduction: 35 days). PUVA treatment was well tolerated and might play a role in the therapy of acute cutaneous GVHD.

Acute Disease↗
PubMed1999

The nature of the mother's tie to her infant: maternal bonding under conditions of proximity, separation, and potential loss.

Attachment has generally been examined from the infant's perspective. We focused on mothers' post-partum thoughts and behaviors. Guided by an ethological approach, maternal bonding was examined under conditions of proximity, separation, and potential loss. Ninety-one mothers were interviewed: mothers of full-term infants who maintained continuous proximity to the infant, mothers of healthy premature infants who were separated from the infant, and mothers of very low birthweight infants who experienced potential loss and prolonged separation. Mothers of term infants reported medium-to-high levels of preoccupations with thoughts of infant safety and well-being. Preoccupations increased with separation (Group 2) and significantly decreased with impending loss (Group 3). Attachment behaviors and representations were the highest among mothers of term infants and declined linearly with the duration of mother-infant separation. Maternal trait anxiety and depression were related respectively to higher levels of preoccupations and reduced attachment behaviors and representations, independent of the infant medical condition and mother-child separation. Discussion focused on the comparability of maternal and infant attachment in relation to the neurobiological system underlying bond formation.

Adult↗