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Biomedical subjects

G F Anderson

Publications and source records attributed to G F Anderson.

At least 127 records · Page 7Linked to original sources
PubMed1985

A neo-urethral enteroplication for urinary continence in a case of cloacal exstrophy.

A four-year-old female, born with cloacal exstrophy, returned for evaluation of her urinary incontinence two years after her initial repair. Her bladder had been turned in at her first operation and had a capacity of approximately 15 cc. Her ureters exited close to the reconstructed introitus. At reoperation, her bladder measured 3.5 cm in length and appeared to be well healed and of normal consistency. An anterior wall bladder flap was created which was based at the dome and was reflected 180 degrees cephalad. The bladder was then tubularized over a #10 french catheter to create a "neo-urethra" of 6 cm in length. Both ureters were reimplanted into an intestinal conduit, constructed 18 cm long, in a nonrefluxing fashion. The distal, oversewn, end of the conduit was sewn down into the pelvis, at the level of the bladder neck and posterior to the "neo-urethra." The end of the neo-urethra was anastomosed to the anterior wall of the intestinal reservoir, which was then plicated circumferentially around the neo-urethra in a manner very similar to the construction of a Nissen fundoplication for gastro-esophageal reflux. Pressure in the reservoir serves to keep the neo-urethra closed so that urine cannot escape until the neo-urethra is intubated. She is currently continent of urine with a successful program of clean intermittent catheterization. Her upper tracts remain undilated and are free of intestinal-ureteral reflux. Her urine is sterile.

Child, Preschool↗
PubMed1985

Beta adrenergic receptors in human cavernous tissue.

Beta adrenergic receptor binding was performed with 125I iodocyanopindolol on human cavernous tissue membrane fractions from normal tissue and transsexual procedures obtained postoperatively, as well as from postmortem sources. Isotherm binding studies on normal fresh tissues indicated that the receptor density was 9.1 fmoles/mg. with a KD of 23 pM. Tissue stored at room temperature for 4 to 6 hours, then at 4C in saline solution for 19 to 20 hours before freezing showed no significant changes in receptor density or affinity, and provided evidence for the stability of postmortem tissue obtained within the same time period. Beta receptor density of 2 cavernous preparations from transsexual procedures was not significantly different from normal control tissues, and showed that high concentrations of estrogen received by these patients had no effect on beta adrenergic receptor density. Displacement of 125iodocyanopindolol by 5 beta adrenergic agents demonstrated that 1-propranolol had the greatest affinity followed by ICI 118,551, zinterol, metoprolol and practolol. When the results of these displacement studies were subjected to Scatfit, non-linear regression line analysis, a single binding site was described. Based on the relative potency of the selective beta adrenergic agents it appears that these receptors were of the beta 2 subtype.

Adrenergic beta-Agonists↗
PubMed1985

Quantitation and stability of cholinergic receptors in human bladder tissue from post surgical and postmortem sources.

Ligand binding for cholinergic muscarinic receptors with (3H) quinuclidinyl benzilate was performed on human detrusor smooth muscle from post surgical and postmortem sources. Following cystectomy, detrusor smooth muscle was serially sampled over an interval of 0 to 9 hours. (3H) quinuclidinyl benzilate binding on individual samples indicated that the total receptor density remained relatively unchanged. Postmortem specimens obtained from patients ranging in age from 1 day to 82 years were also assayed and the cholinergic receptor density was found to range between 18.4 to 82.1 fmoles/mg. of protein. All of the affinity constants from both sources were also in a relatively narrow range of 20.0 to 99.0 pmolar. The results of this study provide evidence for the usefulness of postmortem human tissue for evaluating cholinergic receptors in normal and dysfunctional bladder states.

Adolescent↗
PubMed1985

Current concepts in the management of common urologic problems in infants and children.

Vesicoureteral reflux has the potential to cause irreversible renal damage if undiagnosed and untreated. It is important to have a high index of suspicion for the existence of a urinary tract infection in infants and children with any nonspecific generalized illness. Once a UTI is documented, appropriate antibiotic therapy must be started and continued until the urinary tract has been adequately evaluated radiographically. If vesicoureteral reflux is found to exist, appropriate medical or surgical therapy must be instituted to prevent further episodes of pyelonephritis.

Child↗
PubMed1985

Evidence for oxytocin receptors in the urinary bladder of the rabbit.

Experiments were performed on isolated detrusor smooth muscle from New Zealand White rabbits. Oxytocin was shown to exhibit high intrinsic contractile activity on isolated strips of detrusor muscle, where the maximum contractile amplitude was 12% greater than control responses to 1 microM carbachol. Repeated applications of 1 microM oxytocin were associated with tachyphylaxis representing a 49% decrease in the amplitude which became reproducible after several applications without further decay of contractile strength. Dose-response experiments indicated that threshold contractions to oxytocin occur at 3 nM and were maximum at 10 microM with mean effective concentration of 125 nM. The contractile responses to 1 microM oxytocin were not antagonized by phentolamine, atropine, methysergide, saralasin, or naloxone, but were partially inhibited by 1 microM of indomethacin. Ligand binding studies on partially purified membrane preparations from detrusor smooth muscle were performed over a range of 78 pM to 10 nM with 125I-labelled oxytocin. Scatchard analysis of specific bound receptors indicated a KD of 2.5 nM and Bmax of 187 fmol/mg protein and a second compartment that was unsaturable at the concentrations of ligand employed. Nonspecific binding ranged from 36 to 77% of the total binding.

Animals↗
PubMed1985

Thrombin-elicited contractile responses of aortic smooth muscle.

Human alpha-thrombin at physiologically relevant concentrations of 0.75 to 225 nM (0.01 to 22 clotting units/ml) caused rabbit thoracic aorta to slowly contract in isolated organ baths. Near maximum contractile tension (10% below the irreversible contraction caused by 22 units/ml) was slowly generated by 75 nM alpha-thrombin (8 units/ml) over 18 min and was 50% that of the norepinephrine (NE) control. The initial tonus could only be regained by repeated washing and 60 min equilibration. Tissues were refractory to a second 75 nM alpha-thrombin challenge but responded fully to 1.0 microM NE. Conversion of human alpha-thrombin to nonclotting but estero/amidolytically active gamma-thrombin (less than 0.1% clotting activity) or nitration of the enzyme (1% clotting activity) did not interfere with the contractile activity, whereas chemical conjugates of the parent enzyme at the catalytic site were inactive. Neither atropine, phentolamine, nor indomethacin blocked the thrombin-induced contractions, whereas D-600 was markedly inhibitory. Preincubation of the tissue with inactive forms of thrombin did not prevent the alpha-thrombin-induced response. Removal of the vascular endothelium did not prevent contraction. Aorta preparations with intact endothelium relaxed in the presence of very low concentrations (0.75 to 750 pM) of alpha-thrombin prior to contracting in response to higher concentrations during cumulative dose-response experiments. Our data suggest that catalytically active thrombin forms (alpha- or nonclotting beta- and gamma-thrombins) may have hemostatic functions at the vascular levels in hemostasis.

Animals↗
PubMed1985

Predicting hospital readmissions in the Medicare population.

Using a nationally random sample of Medicare beneficiaries, we developed a multivariate logistic model that identified a series of factors that predict readmission to an acute care hospital within 60 days of discharge. Our regression results show that 10 variables are statistically significant predictors of readmissions, with the patient's disease history and diagnosis among the best predictors. Our results can be used by peer review organizations to evaluate the quality of care provided by different hospitals as well as by physicians and social workers to improve discharge planning.

Demography↗
PubMed1984

Hospital readmissions in the Medicare population.

In order to examine the proportion of Medicare expenditures attributable to repeated admissions to the hospital, we assessed the frequency with which 270,266 randomly selected Medicare beneficiaries were readmitted after hospital discharge between 1974 and 1977. Twenty-two per cent of Medicare hospitalizations were followed by a readmission within 60 days of discharge. Medicare spent over $2.5 billion per year (24 per cent of Medicare inpatient expenditures) on such readmissions between 1974 and 1977. Analogous expenditures in 1984 could approach $8 billion. Even a small decrease in the readmission rate could result in substantial savings for the Medicare program. The recently enacted prospective-payment legislation, however, creates economic incentives that could increase readmission rates. Attempts by professional review organizations or others to develop hospital readmission profiles will need to control for patient and hospital characteristics that are correlated with the likelihood of readmission. Further study of such characteristics could help identify high-risk patient groups for whom increased outpatient supports might prove cost effective.

Aged↗
PubMed1984

Evidence for angiotensin II receptors in the urinary bladder of the rabbit.

Dose-response (DR) curves for several angiotensin analogs were examined on isolated rabbit detrusor strips with washout and rest between each addition. The order of potency was [Val5]-angiotensin II greater than [Ile5]-angiotensin II greater than [Ile5]-angiotensin I greater than [Val4]-angiotensin III. Repeated cumulative DR to [Val5]-AII resulted in a gradual increase in potency and intrinsic activity for four DR. However, the maximum force generated occurred at lower agonist concentrations and was less than that of the single methods, suggesting tachyphylaxis. Atropine (1.0 microM) shifted the cumulative DR curve downward, suggesting some cholinergic component possibly involving a presynaptic site of action. The magnitude of field-stimulated atropine-resistant contractions was reduced by both 1.0 and 10 microM saralasin as well as 10 microM naloxone. Tissue binding with 125I-labelled angiotensin II on isolated detrusor smooth muscle membranes indicated specific binding saturation occurred at 14.3 fmol/mg with a KD of 0.72 nM in EDTA-Tris buffered saline. Thus our results show that angiotensin II (AII) receptors can be demonstrated in destrusor muscle by ligand binding experiments on cell membranes and that saralasin and naloxone partially block atropine-resistant contractions. However, it seems unlikely that AII serves as a neurotransmitter because of the delay in onset of action of exogenous AII in isolated bath experiments and the apparent inability of saralasin to totally abolish the atropine-resistant field-stimulated preparation. If AII serves a role in neurotransmission it most probably is as a neuromodulator.

Angiotensin II↗
PubMed1984

Beta adrenoreceptors in the rabbit bladder detrusor muscle.

This study examines the beta adrenergic receptors of the rabbit detrusor smooth muscle, employing [125I]iodocyanopindolol (ICYP) as a ligand for the binding of beta adrenergic receptors. Saturation binding experiments on the isolated membrane fraction yielded a KD for ICYP of 14.7 pM and a maximum binding of 147.6 fmol/mg of protein. Displacement of labeled ICYP by a series of beta adrenergic agents yielded the following KD values for the combined high and low affinity binding sites: I-propranolol, 0.76 nM; ICI 118,551, 1.7 nM; zinterol, 38.0 nM; metoprolol, 3.5 microM; and practolol, 61.4 microM. When these displacement experimental results were compared to KD values from other reported binding studies with ICYP for beta adrenoreceptors, both the order of potency and the KD values indicated primarily beta-2 adrenergic receptor subtypes. Computer program Scatfit analysis of the displacement curves indicated a single slope and affinity constant for all five beta adrenergic agents. Hofstee plots for zinterol, ICI 118,551 and metoprolol, however, were not linear and indicated that minor populations of beta-1 adrenoreceptors were also present as both high and low affinity binding sites could be defined. It is concluded that the primary receptor population is beta-2 and that this tissue is heterogenous with a small population of beta-1 adrenoreceptors representing approximately 13 to 23% of the total beta adrenoreceptor population.

Animals↗
PubMed1984

Purchase examinations for performance horses.

Performance horses should be thoroughly examined before sale to detect any defects that could render them unsuitable for the purchaser's intended use. With the horse in its stall, the eyes, nasolacrimal puncta, external ear canals and mouth are examined, the rectal temperature measured and the heart, lungs, trachea and sinuses auscultated. Moving the horse out of the stall, the head, parotid glands, mandibular lymph nodes, larynx, neck muscles, jugular veins and cervical vertebrae are inspected. The scapula, point of the shoulder, withers, tuber sacrale and point of the hip are palpated, after which the ventrum, tail, and pelvic and thigh muscles are examined. Structures of all limbs and feet are palpated and inspected for disease and evidence of past surgery. The horse is then worked, on a longe line and under saddle, to evaluate limb carriage and gait. Radiography and other diagnostic procedures are performed as indicated.

Animals↗
PubMed1983

ECT in the neuroleptic malignant syndrome: case report.

Two patients are described who presented with clinical features of catatonia and fever, and were retrospectively diagnosed as having neuroleptic malignant syndrome (NMS). In both cases, ECT resulted in dramatic reduction of fever and the beginning of overall clinical improvement. It is postulated that the beneficial effect of ECT resulted from increased dopamine turnover in the brain. ECT should be considered in cases of NMS in which there is life-threatening fever.

Adult↗
PubMed1982

Survival in a heat stroke victim with a core temperature in excess of 46.5 C.

Presented is a case report of a 52-year-old male heat stroke victim. The patient presented in deep coma with a temperature above 42 C. Following rapid assessment, the patient was intubated, rehydration was begun, and he was externally cooled with ice bags and internally cooled with ice water gastric lavage. After 25 minutes the patient's core temperature was measured at 46.5 C (115.7 F). Multiple organ system failure developed over the ensuing days. With aggressive care, the patient improved dramatically and was discharged at prior baseline status on the 24th day of hospitalization. This case now represents the highest human body temperature elevation reported without permanent residua.

Body Temperature↗
PubMed1982

Evidence for a prostaglandin link in the purinergic activation of rabbit bladder smooth muscle.

Two independent pathways for contraction coupling are described for the cholinergic and ATP activation of rabbit detrusor smooth muscle. Both ATP (0.1 mM) and carbachol (1.0 microM) promote contraction of the rabbit detrusor muscle that can be selectively blocked, the cholinergic activation with atropine and an ATP-induced sustained contraction with indomethacin (indo). Both agonists promoted uptake of 45Ca, but they mediate this response separately because atropine will not effectively block ATP Ca++ uptake but will block carbachol Ca++ uptake. Indo will block the sustained contraction produced by ATP, but will abolish a rapid phasic twitch-like contraction induced by ATP. Indo, however, will partially block Ca++ uptake induced by ATP. Radioimmunoassay for prostaglandin (PG) E in bath perfusate showed that ATP markedly increased synthesis of PGE and this effect was sharply reduced by indo and only partially affected by atropine. This suggests a direct link between the purinergic activation and an increased synthesis of PGE that was indo-sensitive and therefore associated with the sustained ATP-induced contraction. It was further shown that PGE was the probable PG that was released by ATP stimulation rather than PGF2 alpha because radioimmunoassay for PGF2 alpha gave low and inconsistent measurements.

Adenosine Triphosphate↗
PubMed1982

Spare cholinergic receptors in the urinary bladder.

The concentration-effect relationships of carbachol were studied for three different responses of detrusor muscle of rabbit urinary bladder: the mechanical response, the increase of 45Ca uptake and the displacement of [3H]quinuclidinyl benzilate (QNB) from muscarinic receptors. The EC50 for carbachol in production of contractile responses of the detrusor muscle was observed to be 0.27 microM. The 45Ca uptake by detrusor muscle strips was studied by the lanthanum-residual wash out method. Carbachol increased 45Ca uptake with an EC50 of 12.7 microM. [3H]QNB binding was performed on homogenates of rabbit bladder detrusor muscle. By Scatchard analysis, the receptor density was found to be 47.2 fmol/mg of protein and the KD 0.074 nM. The contractile responses, the 45Ca uptake and the specific [3H]QNB binding were all blocked by atropine and so are taken to represent muscarinic receptor-mediated phenomena. Carbachol displacement of [3H]QNB yielded an EC50 of 135 microM and a Kl of 42 microM. It is concluded that the mechanical response requires a much lower concentration of carbachol than that needed for stimulating 45Ca uptake or for occupying [3H]QNB binding sites and that there appears to be approximately a 150-fold muscarinic receptor excess.

Animals↗