Search PubMed⌕ Search

Biomedical subjects

B S Smith

Publications and source records attributed to B S Smith.

At least 37 records · Page 2Linked to original sources
PubMed1990

Ultrastructure of murine trisomy 1 optic cup.

The optic cups of two gestational day 11 trisomy (ts) 1 mouse embryos and a normal littermate control were examined using transmission electron microscopy (TEM). One trisomic embryo had a small lens with a lens stalk; the other was aphakic. The resolution available with TEM allowed detailed evaluation of cell organelles, spatial relationships, and the intra- and extracellular structural environment of the optic cup in normal and abnormal mouse embryos. Differences between the normal littermate and the trisomic optic cups, as well as between the two ts 1 structures, included the following: 1) melanin granules in the retinal layer and intraretinal space as well as in the pigment layer, 2) neither pseudostratified nor cuboidal neuroepithelium in trisomic optic cups, 3) increasing cell lysis with severity of eye defect, 4) fusion between retinal and pigment layer cells and cells from the pigment layer and head mesoderm. This investigation not only confirmed some of the abnormal morphology found in light microscopic studies of ts 1 at this gestational age but also identified other anomalies in the ts 1 eye that may play a part in the dysgenesis of this organ. The roles of larger than normal intercellular lacunae, disorganized microtubules, and the connections between different cell types in the ts 1 optic cup require further investigation.

Animals↗
PubMed1990

The measure of balance in sitting in stroke rehabilitation prognosis.

To test the hypothesis that recovering stroke patients with initially good sitting balance or those who develop good sitting balance during rehabilitation have better Barthel Index-based functional assessment outcomes than recovering stroke patients with poor sitting balance, we prospectively studied 24 of 25 consecutive stroke patients admitted to a tertiary-care hospital rehabilitation unit. Sitting balance, a prerequisite for most functional activities, was scored using a four-point scale evaluating static and dynamic sitting balance on admission to the rehabilitation unit and weekly until discharge. Functional status was assessed using the Barthel Index 4 or 12 weeks after the stroke. We found a strong positive correlation between Barthel Index score and each weekly sitting balance score. Multiple evaluations over time identified those patients whose sitting balance improved during rehabilitation in our unit; after grouping the patients into those with normal, improved, and poor sitting balance, we found a significant difference in the Barthel Index scores among the three groups. The group of patients whose sitting balance improved had higher Barthel Index scores than the group whose sitting balance did not improve. Ongoing evaluation of sitting balance can be helpful in anticipating functional status at discharge in stroke patients undergoing comprehensive rehabilitation.

Aged↗
PubMed1990

Shedding pattern of Staphylococcus aureus from bovine intramammary infections.

Twenty-one quarters of seven cows were experimentally infected with Staphylococcus aureus (ATCC 29740) to study the shedding pattern in quarter milk samples. Of 991 consecutive quarter milk samples collected from infected quarters during the trial, 745 were positive for S. aureus by bacteriological culture. The sensitivity of a single quarter milk sample to determine infection status of a quarter was 74.5% based on the mean of each gland's recovery pattern. Sensitivity of bacterial culture increased to 94% and 98% by including a second and a third consecutive sample. Because S. aureus is shed in a cyclical manner from mammary glands, consecutive samples would be advisable for accurate diagnosis of infected quarters.

Animals↗
PubMed1990

Effect of low-dose oral contraceptive on gonadotropins, androgens, and sex hormone binding globulin in nonhirsute women.

The effectiveness of a low-dose oral contraceptive (OC) in suppressing plasma levels of gonadotropins, ovarian, and adrenal androgens and stimulating sex hormone-binding globulin (SHBG) was evaluated prospectively in nonhirsute women. Thirty-three women ingested 35 micrograms of ethinyl estradiol and 1 mg of norethindrone beginning within day 1 to 5 of the menstrual cycle. Baseline levels of luteinizing hormone, follicle-stimulating hormone, total testosterone (T), androstenedione (A), dehydroepiandrosterone sulfate (DHEAS), and SHBG were obtained before ingestion of the OC and repeated after 3, 6 and, 9 months of OC use on day 1 to 5 of the OC "cycle". A significant suppression of gonadotropin levels is seen in nonhirsute women. Sex hormone binding globulin is consistently stimulated by the low-dose OC. A significant suppression of T and DHEAS is observed. No change was seen in levels of A. The demonstrated effects become evident at 3 months and are maintained at 6 and 9 months.

Adolescent↗
PubMed1990

Questions asked by patients and their support groups during family conferences on inpatient rehabilitation units.

Although discharge planning from rehabilitation units is discussed in social service and nursing literature, no studies have documented what information the family specifically seeks in preparing for the patient's discharge. In order to gain insight into this issue, the residents assigned to two rehabilitation units were asked to paraphrase and transcribe all questions asked by randomly selected patients and their support groups during family conferences. Forty-six conferences with 45 patients were evaluated, and 213 questions were recorded. Each question was placed into one of ten categories, based on the topic of the question. The most common topic about which information was sought was medical issues not directly related to the primary rehabilitation diagnosis (17% of all questions). Discharge planning was the second most common topic (16%). Thirty-one percent of all questions were related to medical issues. The information derived from this study will help rehabilitation professionals to be better prepared for family conferences and discharge planning.

Family↗
PubMed1989

Histochemical analysis of extracellular matrix material in embryonic trisomy 1 mouse eye.

Trisomic animals produced from mice doubly heterozygous for Robertsonian translocation chromosomes [Rb(1.3)/Rb(1.10)]consistently show eye defects (e.g., aphakia, microphakia, and retention of lens stalk). To determine if changes in distribution or composition of extracellular matrix material may be a factor in development of these defects, eye structures of trisomy (ts) 1 embryos and normal littermates were studied histochemically using the following methods: Alcian blue 8GX, pH 2.5; periodic acid-Schiff (PAS), Alcian blue/PAS combined; high-iron diamine (HID), and HID/Alcian blue combined. Eye development was divided into stages to account for the known delay in ts 1 mouse development. Differences were found in staining patterns as early as stage 1. In later stages, the most consistent difference was an increased period of contact between lens and optic cup due to retardation of interface matrix dissolution between these rudiments in ts 1 embryos. Eyes in which this occurred had abnormally shaped lenses. Overall, the ts 1 optic cup appeared to have fewer staining abnormalities and dysmorphology than did the lens or interface matrix. Triplication of a chromosome may indirectly alter temporal and spatial organization of extracellular matrix through action on cells responsible for the production of this material. Possible mechanisms of action are discussed.

Animals↗
PubMed1989

Mitosis in embryonic trisomy 1 mouse eye.

Trisomy 1 embryos consistently show eye defects (e.g., aphakia, microphakia, retention of lens stalk). To determine if the plane of division of mitotic figures is abnormal in the eyes of these animals, trisomic embryos (9.5 through 12 gestational days) were produced from mice doubly heterozygous for Robertsonian translocation chromosomes [Rb(1.3)/Rb(1.10)]. To accommodate for the known delay in trisomic embryo development, animals were grouped according to stages of eye development rather than to gestational age. Serial sections were evaluated without knowledge of karyotype for orientation of mitotic figures (parallel, perpendicular, oblique) in lens, optic cup, and diencephalon. Location of mitotic figures was scored as apical (nearest the lumen), middle, and basal. Numerous anomalies were noted in trisomic eye development. No difference was found between orientation of mitotic figures in the lens and optic cup of trisomy 1 and normal embryos. Location of mitotic figures in trisomy 1 lens was significantly different from that of normal littermates. The data confirm earlier studies that trisomy 1 affects the eye, and they tend to corroborate evidence that this trisomy affects the lens more than it affects the optic cup.

Animals↗
PubMed1989

Criteria for selection of physical medicine and rehabilitation residents. A survey of current practices and suggested changes.

The growing number of medical graduates seeking residency training in Physical Medicine and Rehabilitation (PM&R) has made the resident selection process increasingly difficult. This circumstance has prompted a search for more efficient selection criteria. Forty-one PM&R residency program directors in the United States and Puerto Rico completed a survey on the way they selected their residents. The results indicate that personal applicant characteristics, as determined by interview, were more important than academic criteria in ranking residency candidates. Of the academic variables presented, participation in a PM&R elective at the program director's hospital and the Dean's letter were rated highest. The interview experience has a major influence on the ranking of an applicant for acceptance into a PM&R training program. Academic criteria should have more influence on applicant selection than they do at present. In addition, early identification and vigorous recruitment of resident candidates with an interest in research is essential for increasing the number of academic physiatrists within our specialty.

Educational Measurement↗
PubMed1989

Above-knee amputation with insidious pulmonary embolism and hypercoagulability secondary to protein C deficiency.

Pulmonary embolus can have insidious onset and unusual etiology. This case report of a 35-year-old woman with hyperthyroidism, atrial fibrillation, and an above-knee amputation demonstrates the subtle presentation of pulmonary emboli. On the rehabilitation ward of a tertiary care hospital, the patient developed undulating fever to 39.6C, rapidly worsening peripheral vascular disease, and pulmonary emboli. Eventually, a protein C deficiency was found; institution of appropriate therapy resulted in rapid improvement. This case reminds physiatrists to evaluate thoroughly the cause of pulmonary thrombi. Currently available assays permit rapid elucidation of factor deficiencies in the workup of the hypercoagulable state.

Adult↗
PubMed1989

Intramedullary fixation of unstable distal radius fractures. A method of fixation allowing early motion.

During a four-year period, we have treated unstable fractures of the distal radius with closed anatomic reduction and insertion of a Rush intramedullary rod through a small dorsoradial wrist incision, followed by early controlled range of motion. In an attempt to reduce the stiffness commonly seen in the fingers, wrist, and elbow, a simple method of more stable fixation and early motion was instituted. Patient assessment using common anatomic and functional classification systems revealed good to excellent results in 35 of 36 patients (98%). Only three patients had complications, and these were all minor in nature. Three rods were removed, all because of prominence and irritation of the tip of the rod over the radial styloid. The procedure is technically reproducible, and has a very high rate of patient acceptance and satisfaction.

Adult↗
PubMed1988

Rickets associated with vitamin D deficiency in young sheep.

An outbreak of rickets in sheep under a year old (hoggs) appeared clinically as stiffness and rotation of the carpal joints. Histological studies confirmed the diagnosis and biochemical analyses of blood demonstrated a primary vitamin D deficiency.

Animals↗
PubMed1987

Effect of vitamin D supplementation during pregnancy on the vitamin D status of ewes and their lambs.

Pregnant ewes were injected intramuscularly with 300,000 iu of vitamin D3 in a water miscible vehicle either 10, seven or four weeks before the expected lambing date and the effects on plasma concentrations of 25-hydroxyvitamin D3 were monitored. The concentrations increased quickly and remained high at parturition but at no time were they outside the normal physiological range. The concentrations in the plasma of the newborn lambs were higher than in uninjected controls and were well correlated with the concentrations in their mothers. Dosing pregnant ewes with 300,000 iu of vitamin D3 in a rapidly available form, approximately two months before lambing, provided a safe means of increasing the vitamin D status of the ewe and the newborn lamb by preventing the seasonally low concentrations of 25-hydroxyvitamin D3.

Animals↗
PubMed1987

Development of the embryonic trisomy 1 mouse.

Trisomic and normal control embryos 9.5 through 12 gestational days were examined externally and on serial section with standard light microscopy techniques. Trisomic embryos showed significant retardation in length, weight, optic angle, and somite numbers at most times (p less than .05), and were 1/2 day behind normal animals in overall development. The eye showed the most defects, and these appeared at every period. They included aphakia, large intraretinal space, and dysmorphia of optic cup layers. Brain defects were found at all times. The most common were narrow brain vesicles and folding of the vesicle walls. Some animals showed neural tube defects. The major defect in neural crest derivatives was deficient frontonasal processes in the most defective embryos. The study supports the conclusion of previous investigators that Ts 1 is a syndrome of growth and developmental retardation with a wide range of defects. Definitive evidence, previously lacking, indicates that developmental delay and defective morphogenesis are apparent before 11 days of gestation. In addition, according to our measurements, optic angles are larger in trisomic mice than in normal littermates. This is in contrast to the only previous investigation that included such measurements. Our data do not give definitive support to the suggestion that trisomy 1 belongs to the holoprosencephaly-cyclopia spectrum. However, the hypothesis that murine trisomy 1 shows a parallel in development to human trisomy 13 is not supported by our data. Possible causal mechanisms for the defects and developmental delay are discussed.

Animals↗
PubMed1986

Subarachnoid hemorrhage due to anterior spinal artery aneurysm.

This case report describes a 29-year-old man with subarachnoid hemorrhage due to an anterior spinal artery aneurysm. Surgical obliteration of the aneurysm was successful. This is the sixth reported case of an isolated symptomatic aneurysm of a spinal artery.

Adult↗