Search PubMed⌕ Search

Biomedical subjects

A Weller

Publications and source records attributed to A Weller.

At least 19 recordsLinked to original sources
PubMed2002

[Intracameral anesthesia with lidocaine in cornea guttata].

BACKGROUND: Combined topical and intracameral anesthesia has become increasingly popular in cataract surgery. We analyzed the use of intracameral anesthesia in patients with corneal dystrophy who had undergone cataract surgery. PATIENTS AND METHODS: We measured the number of endothelial cells in 40 eyes with Fuchs' corneal endothelial dystrophy preoperatively as well as three times postoperatively (after 1 day, 4 weeks, and 3 months). Performing sponge anesthesia, the additional application of 0.15 ml lidocaine 1% was randomized. RESULTS: The lidocaine group showed the following loss of endothelial cells in the central cornea: 1 day postoperatively 9.2%, 4 weeks later 9.7%, and 3 months after surgery 10.7%. The other group had a postoperative loss of endothelial cells in the central cornea of 8.8% (1 day), 9.3% (4 weeks), and 10.5% (3 months). No significant differences between the two groups were observed. CONCLUSIONS: Cornea guttata is not a contraindication for the use of intraocular lidocaine.

Aged↗
PubMed2002

Menstrual synchrony and cycle variability: a reply to Schank (2000).

Menstrual synchrony has been measured by a change over time, to capture the "process" of synchronization or by examining a sample of women who have been together for a number of months ("state" synchrony). We have proposed and used a method for calculating "state" synchrony. On the basis of the results of a computer simulation, Schank (Schank, J.C., 2000. Menstrual-cycle variability and measurement: further cause for doubt. Psychoneuroendocrinology 25, 837-847) argues that our method is biased towards finding synchrony and that the degree of error is an increasing function of cycle variability. We show that Schank's model is based on unfounded assumptions. Contrary to Schank's assertion, on which much of the critique is based, there is no evidence that cycle variability is actually large in samples with "state" synchrony. Our reports are valid; and our method is supported both by convergent validity and by the use of statistical "random control" groups.

Bias↗
PubMed2001

Cholecystokinin receptor antagonists increase the rat pup's preference toward maternal-odor and rug texture.

The role of the cholecystokinin (CCK) system in mediating the infant's natural preferences toward maternal-related stimuli was examined by peripheral administration of selective CCK(A) and CCK(B) receptor antagonists (Devazepide and L-365,260, respectively) to 11-12-day-old rats and presenting them with a 3-minute preference test. In Experiment 1, the choice was between two floor textures, rug and plywood; the time spent on the relatively preferred side (rug) was measured. In Experiment 2, the odor of maternal faces emanated from one end of the test arena; time spent near that end was measured. These sensory stimuli were chosen as they represent olfactory and tactile aspects of the dam and nest. Compared to controls, both CCK receptor antagonists selectively increased the time spent on the preferred side, in both experiments, without affecting axillary temperature or locomotor activity. The results suggest that CCK may mediate and attenuate the infant's attraction toward naturally preferred stimuli.

Animals↗
PubMed2001

Selective breeding for infant vocal response: a role for postnatal maternal effects?

N:NIH rats were selectively bred on the basis of high or low rates of ultrasonic vocalization (USV) response to isolation at 10 days of age (Brunelli et al., 1997: Dev Psychobiol 31:255-265). To examine the possibility of postnatal maternal effects in the generational transmission of divergent traits, pups were cross-fostered shortly after birth between dams of the two lines (Low- and High-USV). Controls were fostered to dams of the same line (in-fostered). Additional (population) control data were obtained from the entire 13th generation of the selectively bred lines. USV rates of cross-fostered pups in each line were not significantly different from rates of in-fostered pups of the same line. High USV line pups cross-fostered to Low USV line dams weighed significantly less than in-fostered pups, on the day of testing. The results provide no evidence for a postnatal maternal contribution to the USV phenotype. Prenatal and/or perinatal maternal effects have not been ruled out.

Animals↗
PubMed2001

[Capsular rupture in cataract operations with sponge surface and intra-anterior chamber anesthesia].

BACKGROUND: Combined topical and intracameral anaesthesia has become increasingly popular in cataract surgery. The purpose of this study was to determine the risk of capsular lesions with an intact motility during surgery. PATIENTS AND METHODS: In a prospective clinical study, we analyzed 2000 phacoemulsifications with IOL implantation performed by an experienced surgeon with combined sponge and intracameral lidocain anaesthesia. Preoperatively two grades of difficulty of the surgical procedure were defined. RESULTS: Operations were carried out on 1,658 patients with a (grade 1) low degree and 342 patients (grade 2) with a high degree of difficulty (17.1%). Capsular lesions occurred in 17 operations (0.85%), 15 in cases with a high degree of difficulty (88%). In 12 of these, an anterior vitrectomy was necessary and in 1 operation a pars plana vitrectomy after application of additional retrobulbar anaesthesia was performed. CONCLUSIONS: In this study the incidence of capsular lesions was not increased compared to other methods of anaesthesia. Anterior vitrectomy with the patient under combined sponge and intracameral anaesthesia, was possible without retrobulbar anaesthesia.

Aged↗
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↗