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Biomedical subjects

B Williams

Publications and source records attributed to B Williams.

At least 415 records · Page 23Linked to original sources
PubMed1986

Phosvitin isolation from fish eggs: methodological improvements including 'specific' phosvitin precipitation with ferric ion.

Modifications of the method of Wallace et al. [Can. J. Biochem. 44, 1647-1655 (1966)] for phosvitin isolation from vertebrate eggs were devised to enhance the method's general effectiveness. Phosvitins which do not precipitate on dilution from solutions of their lipovitellin complexes may be selectively adsorbed onto, and desorbed from, DEAE-cellulose. Phosvitins which are too small for dialysis or ultrafiltration may be concentrated or desalted by precipitation with stoichiometric amounts of ferric ions, followed by iron removal with EDTA on gel filtration. Since phosvitin distribution among ammonium sulfate fractions depends on initial protein and salt concentrations in a species-specific manner, pilot experiments are needed to establish conditions for optimal fractionation.

Amino Acids↗
PubMed1986

The nosocomial colonization of T. Bear.

A national effort to reduce nosocomial infections includes a program developed at the National Institutes of Health to encourage handwashing in hospitals and day care centers. The program promotes a symbolic teddy bear (T. Bear) with slogans to remind hospital personnel and patients to practice handwashing. One of the items used is a stuffed toy T. Bear to be dispensed to the hospitalized child. Considering the manner in which children handle stuffed toys, we suspected the T. Bear might serve as a "fomite" for transmission of nosocomial microbes. A prospective study of 39 sterilized T. Bears revealed that all became colonized with bacteria, fungi, or both within 1 week of hospitalization. Hospital acquired organisms cultured from the T. Bear included Staphylococcus epidermidis, Staphylococcus aureus, alpha streptococci, Corynebacterium acnes, Micrococcus sp, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, Bacillus sp, and species of Candida, Cryptococcus, Trichosporon, Aspergillus and others. Concomitant cultures of the patients revealed similar isolates. Although the T. Bear handwashing campaign should not be discredited, the promotional toy may pose an unnecessary expense and hazard and should not be used in hospitals or day care centers.

Attitude of Health Personnel↗
PubMed1986

Surgery of arachnoid pouches.

An anecdotal presentation of some features of subarachnoid pouches stresses the variable clinical and morphological features. Hydrocephalus is commonly associated but is not always a cause nor a result of the pouches. The nature of the valvular action is unclear but most probably usually takes the form of plugs of nervous tissue, compression of perivascular spaces in the depths of sulci or else meningeal flaps forming slits in the CSF pathways. The nature of the filling force is almost certainly pulsatile and dependent upon venous impulses generated within the thoraco-abdominal cavities. Treatment may need to be directed against the pouch, or the hydrocephalus. Treatment of the valvular mechanism alone by dissection is frequently sufficient. Opening the pouch widely to the ventricular system may also be of value. Post-operative surveillance is necessary.

Brain↗
PubMed1986

Progress in syringomyelia.

Syringomyelia management is showing some progressive improvements following surgical methods of investigation and treatment. Investigation of simultaneous pressure changes in the cerebrospinal fluid pathways has illustrated the importance of craniospinal pressure dissociation in impacting the cerebellar and medullary tissues in the foramen magnum in hindbrain related syringomyelia. Such pressure differences may be referred to as 'suck' and similar changes are to be found in non-hindbrain related forms of syringomyelia such as those associated with spinal arachnoiditis. When cavities have formed then impulsive movements may occur with them and enlargement of the cavities may be continued by sloshing of the fluid within them. Investigations have been improved following the widespread use of water soluble contrast media and CT scanning with reconstructions after myelography. A definite relationship between birth injury and hindbrain related syringomyelia has been established especially with cases showing arachnoiditis. The nature of the relationship to hindbrain hernia and basilar invagination remains unclear. Magnetic resonance imaging holds great promise particularly in showing hindbrain deformation in new-born babies, showing whether or not a communication commonly exists between the fourth ventricle and the cavities within the spinal cord in early childhood and also in outlining the changes in the spinal cord in the presence of acute traumatic paraplegia. Treatment still relies upon valved ventricular to extrathecal shunts for hydrocephalus, cranio-vertebral decompression to prevent suck and drainage of the syrinx in appropriate cases. Syrinx to extrathecal shunting may be preferred to shunts to the subarachnoid space. The peritoneum and the pleura are favoured sites and a valve is not necessary. The advances for the future may depend on earlier diagnosis and greater understanding of the mechanisms of pathogenesis in which MRI seems likely to play an increasingly important part.

Arnold-Chiari Malformation↗
PubMed1986

Lupus erythematosus keratoconjunctivitis.

A patient with systemic lupus erythematosus and a three-month history of bilateral follicular conjunctivitis had both a superficial and deep culture-negative keratitis. Although SLE interstitial keratitis is uncommon, it must be recognized as a definite clinical entity. Its prompt recognition and treatment with corticosteroids may quickly bring about improvement, whereas if it is unrecognized, corneal scarring and loss of vision may follow.

Adult↗
PubMed1986

Congenital lower nasolacrimal duct anomaly: a case report.

A congenital anomaly of the nasolacrimal system not previously described is reported. The apposition of the distal end of the nasolacrimal duct was not with the nasal cavity as normally occurs prior to birth but to the external skin. As a result the child presented with difficulty with tear drainage and consequent infection--"neonatal conjunctivitis" followed by a facial abscess at the left lower border of the nose. Recent embryological studies suggest that this anomaly is due to failure of complete separation and migration of the epithelial rod most distal from the surface ectoderm to the inferior meatus of the nasal cavity. This distal remnant of the nasolacrimal duct thus remains juxtaposed to the surface ectoderm of the face on the lateral aspect of the alar nares. The modern concept of the embryological development of the nasolacrimal system is reviewed.

Eye Diseases↗
PubMed1986

Conformationally constrained tachykinin analogs which are selective ligands for the eledoisin binding site.

We have prepared a series of conformationally constrained hexapeptide analogs of substance P which are 500-1500-fold more potent as inhibitors of 125I-labeled Bolton Hunter-conjugated eledoisin binding to rat brain cortex membranes than as inhibitors of 125I-labeled Bolton Hunter-conjugated substance P binding. These analogs stimulate guinea pig ileum contraction (ED50 1-16 nM) and stimulate rat vas deferens contraction (ED50 2-4 microM). However, these peptides are poor stimulators of rat salivation (greater than 40 nmol/100 g body weight). Thus, based on both their receptor potency and pharmacological potency, these peptides are potent and selective tachykinin analogs. These data indicate that a specific carboxyl-terminal conformation is recognized by the 125I-labeled Bolton Hunter-conjugated eledoisin binding site and that this conformation is different from the conformation recognized by the 125I-labeled Bolton Hunter-conjugated substance P binding site. Hexapeptides containing phenylalanine, isoleucine, and valine identical with the carboxyl-terminal sequences of substance P, eledoisin, and neurokinin B, respectively, were nearly equipotent as inhibitors of 125I-labeled Bolton Hunter-conjugated eledoisin binding. The valine analog was only approximately 5-fold less potent than the isoleucine and phenylalanine analogs as an inhibitor of 125I-labeled Bolton Hunter-conjugated substance P binding. Thus, unknown determinants in the amino-terminal sequences of substance P must strongly contribute to the carboxyl-terminal peptide selectivity and conformation. The contraction of guinea pig ileum induced by one of the conformationally constrained analogs is attenuated by pretreatment of the tissue with atropine (2 microM), while that induced by substance P methyl ester, a selective inhibitor of 125I-labeled Bolton Hunter-conjugated substance P binding, is not. Thus, the constrained analog has a higher affinity for the tachykinin receptors in the guinea pig myenteric plexus which are responsible for acetylcholine release than for the tachykinin receptors present on the smooth muscle cells.

Acetylcholine↗
PubMed1985

Effect of applying the Honan intraocular pressure reducer before cataract surgery.

We studied 48 patients undergoing cataract extraction with local anesthesia. In 41 patients, after administering the retrobulbar injection, we applied the Honan intraocular pressure reducer for seven to ten minutes at a pressure setting of 30 mm Hg. Of these 41 patients, 13 received 3-ml injections, 14 received 4-ml injections, and 14 received 5-ml injections. No differences in intraocular pressure related to the quantity of retrobulbar injection were noted. After retrobulbar injection, the mean intraocular pressure for the study population as a whole increased 4.4 mm Hg; after application of the Honan device, it decreased 6.2 mm Hg. In a control group of seven patients, who received 4-ml retrobulbar injections but no applications of the Honan device, mean intraocular pressure increased 6.1 mm Hg immediately after retrobulbar injection and decreased only 0.7 mm Hg after seven to ten minutes.

Bupivacaine↗
PubMed1985

Causes of congenital unilateral pulmonary hypoplasia: a study of 33 cases.

A review of the roentgenograms and clinical records of 33 children with primary congenital underdevelopment of one lung showed that 9 patients had simple pulmonary hypoplasia, 8 had anomalous venous return to the right atrium or the inferior vena cava (scimitar syndrome), 7 had an absence of the ipsilateral pulmonary artery, 7 had an accessory diaphragm, and 2 had a pulmonary sequestration adjacent to a small diaphragmatic hernia.

Bronchopulmonary Sequestration↗
PubMed1985

Protrusive positioners.

Techniques were described for fabricating maxillary and mandibular protrusive positioners for treatment of disk-condyle derangements. Treatment time with the splints varies from 4 to 12 months depending on the age of the patient, the degree of existing symptoms, and patient motivation. At the end of the treatment period and after removal of the splints, the patient may have (1) no pain or internal derangement, (2) no pain but internal derangement with or without reduction, or (3) pain and internal derangement with or without reduction. If dental treatment is required, patients in the first two categories can be treated at a physiologically acceptable treatment position with existing treatment modalities. For patients in the third category, definitive, irreversible stabilization should be reevaluated. For these patients a mandibular cast splint can be changed to an interim splint by replacing the self-polymerizing resin with Isosit (Ivoclar-Vivadent, Schaan, Liechtenstein) or heat-processed acrylic resin.

Age Factors↗
PubMed1985

Posterior fossa subdural empyema.

Seven cases of posterior fossa subdural empyema were treated between 1955 and 1984; 3 of the patients survived. The two sources of infection were otogenic and spread from supratentorial subdural empyema complicating acute frontal sinusitis. Investigations including computerized axial tomography (CT) scans were sometimes equivocal and diagnosis was sometimes delayed. Posterior fossa craniectomy appeared to be the operation of choice; all the patients treated only by posterior fossa burr holes died. Early aggressive surgical intervention in such cases should result in a minimal morbidity.

Adolescent↗
PubMed1985

Pressures recorded during periodontal pocket irrigation.

Pressures arising during periodontal pocket irrigation with 5 ml and 20 ml disposable plastic syringes, a peristaltic pump and a Waterpik pulsating irrigator were measured with an in-line transducer and recorder in 11 patients. Three types of needles were used with each device; disposable 15-gauge straight and angled needles and a 15-gauge angled reusable needle. Measurements were made with the needle tips just within, and 3 mm into the pocket. With both the 5 ml and 20 ml syringes and all needles, pressures of 100- to 500-mm mercury were recorded. With the peristaltic pump, pressures of 70- to 340-mm mercury were recorded with all needles. The Waterpik apparatus produced pressures of not more than 60-mm mercury in all cases.

Dental Devices, Home Care↗