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Biomedical subjects

R L Ferguson

Publications and source records attributed to R L Ferguson.

At least 37 records · Page 2Linked to original sources
PubMed1984

Response of marine bacterioplankton to differential filtration and confinement.

The bacterioplankton community of confined seawater at 25 degrees C changed significantly within 16 h of collection. Confinement increased CFU, total cell number (by epifluorescence microscopy), and average cell volume of bacterioplankton and increased the turnover rate of amino acids in seawater sampled at Frying Pan Shoals, N.C. The bacterioplankton community was characterized by two components: differential doubling times during confinement shifted dominance from bacteria which were nonculturable to bacteria which were culturable on a complex nutrient medium. Culturable cells (especially those of the genera Pseudomonas, Alcaligenes, and Acinetobacter) increased from 0.08% of the total cell number in the seawater immediately after collection to 13% at 16 h and 41% at 32 h of confinement. Differential filtration before confinement indicated that particles passing through a 3.9-microns-, but retained by a 0.2-micron-, pore-size Nuclepore filter may be a major source of primary amines to the confined population. The 3.0-microns filtration increased growth rate and ultimate numbers of culturable cells through the removal of bacterial predators or the release of primary amines from cells damaged during filtration or both.

Amines↗
PubMed1984

Size of suspended bacterial cells and association of heterotrophic activity with size fractions of particles in estuarine and coastal waters.

The size of bacteria and the size distribution of heterotrophic activity were examined in estuarine, neritic, and coastal waters. The data indicated the small size of suspended marine bacteria and the predominance of free-living cells in numerical abundance and in the incorporation of dissolved amino acids. The average per-cell volume of suspended marine bacteria in all environments was less than 0.1 mum. Cell volume ranged from 0.072 to 0.096 mum at salinities of 0 to 34.3 per thousand in the Newport River estuary, N.C., and from 0.078 to 0.096 mum in diverse areas of the Gulf of Mexico. Thus, the free-living bacteria were too small to be susceptible to predation by copepods. In the Newport River estuary, ca. 93 to 99% of the total number of cells and 75 to 97% of incorporated tritium (from H-labeled mixed amino acids) retained by a 0.2-mum-pore-size filter passed through a 3.0-mum-pore-size filter. Although the amino acid turnover rate per cell was higher for the bacteria in the >3.0-mum size fraction than in the <3.0-mum size fraction, the small number of bacteria associated with the >3.0-mum size particles resulted in the low relative contribution of attached bacteria to total heterotrophic activity in the estuary. For coastal and neritic samples, collected off the coast of Georgia and northeast Florida and in the plume of the Mississippi River, 56 to 98% of incorporated label passed through a 3.0-mum-pore-size filter. The greatest activity in the >3.0-mum fraction in the Georgia Bight was at nearshore stations and in the bottom samples. Our data were consistent with the hypothesis that resuspension of bottom material is an important factor in influencing the proportion of heterotrophic activity attributable to particle-associated bacteria.

Journal Article↗
PubMed1984

A mechanistic classification of thoracolumbar spine fractures.

Thoracolumbar spinal injuries are classified on the basis of the mechanical mode of failure of the vertebral bodies. The fractures are presented in seven categories. Emphasis is placed on the injury component causing the fracture patterns. The choice of instrumentation for surgery is based on the surgeon's understanding of these injury patterns.

Fracture Fixation, Internal↗
PubMed1983

Physiologic tremor and microsurgery.

Physiologic tremor hampers the ability of students to learn microsurgical technique. An understanding of normal tremor both as to origin and methods of control would be of help. Physiological tremor arises from both mechanical and neuromuscular sources and is made worse by a number of factors. The "size principle of motoneuron recruitment" is an important physiologic consideration, and the use of biofeedback techniques enables the student to confirm his understanding of the principle. Knowledge of the factors which aggravate physiological tremor allows the microsurgeon to control his own tremor both in the laboratory and in the operating room.

Biomechanical Phenomena↗
PubMed1983

Staged correction of neuromuscular scoliosis.

Anterior release and fusion, combined with tong gravity traction and second stage L-rod instrumentation, establishes correctability and accomplishes circumferential arthrodesis of the spine in neuromuscular scoliosis. From March 1979 through April 1982, nine patients with neuromuscular scoliosis, with an average age of 16.4 years, underwent this two-stage surgical procedure. The parameters investigated included correction of scoliotic deformity, correction of pelvic decompensation, and spinal arthrodesis. The preoperative scoliotic curvature measured 81 degrees and the postoperative curve measured 29.3 degrees, an average correction of 63.8%. Pelvic obliquity was significant in five of nine patients, averaging 36.2 degrees preoperatively. Postoperatively the pelvic obliquity averaged 11.8 degrees, an average correction of 67.4%. One of two pelvic fixation rods rotated out of the pelvis of one patient; roentgenographically he appears to have fused without loss of correction. A second patient has a poor fusion mass by roentgenographic criteria, although she has lost no correction and has had no pain. This technique offers results comparable to other series reporting arthrodesis for neuromuscular scoliosis. It has the advantages of requiring no anterior instrumentation and no postoperative immobilization.

Adolescent↗
PubMed1983

The technique of scoliosis revision surgery utilizing L-rod instrumentation.

Operative treatment of failed scoliosis surgery requires an instrumentation that is readily adaptable to the multiple causes and sequelae of failed spinal surgery. A "modified L-rod" technique is described for segmental spinal instrumentation to treat failed scoliosis surgery. Nine patients underwent 10 scoliosis revision operations, with an average follow-up of 37.1 months. Three neuromuscular, five idiopathic, and one congenital scoliosis were revised. The average blood loss for the L-rod instrumentation was 2,960 ml, and the average operative time was 6.2 h. Four patients had attempted correction of their deformities, with 21.2% improvement. Five cases had triangular base-transverse bar pelvic fixation. None of the 10 revisions had pseudarthrosis at follow-up. No postoperative immobilization was used. Complications included one fracture of a fusion mass below the L-rods, penetration of the skin by a prominent wire with subsequent infection, minimal loss of correction in one case, and one broken wire without loss of correction.

Adolescent↗
PubMed1982

L-rod instrumentation for scoliosis in cerebral palsy.

From April 1977 through September 1980 at the University of Texas Medical Branch, 10 cerebral palsied individuals with total body involvement were surgically treated for their scoliosis. Each underwent L-rod instrumentation either as a definitive procedure or as the second surgery in a two-staged correction and arthrodesis. The average age of the group was 15.6 years and the average curve severity 70.8 degrees. An average correction of 59.9% or 41.5 degrees was obtained; two-stage procedures averaged 7.2 degrees correction per segment as contrasted with 5.4 degrees for single stage surgery. Most patients had regained their preoperative level of function within 2 weeks after L-rod instrumentation. At an average follow-up interval of 2.73 years, all have a solid spinal arthrodesis. On the basis of this experience, we feel that L-rod instrumentation is a more effective adjunct in the surgical management of cerebral palsy scoliosis than combined Harrington-Dwyer instrumentations.

Adolescent↗
PubMed1980

Beta thalassemia minor and cleidocranial dysplasia: a rare combination of genetic abnormalities in one family.

Dentists frequently treat patients who have several coexisting disease processes. When genetic disorders of distinct and separate types are present in several members of one family, it is a finding of considerable interest. A family afflicted with beta thalassemia minor and cleidocranial dysplasia is discussed and their management is presented. Special emphasis must be placed on the inclusion of genetic counseling in the treatment plan of patients with genetically transmissible abnormalities.

Adult↗
PubMed1977

Thioridazine-hydrochloride-associated agranulocytosis.

A patient with thioridazine-hydrochloride-associated agranulocytosis is described and eight previously reported cases are reviewed. This complication is most likely due to a direct toxic effect on the bone marrow. As in our case, markers for an immunologically mediated mechanism have not been found. Thioridazine-hydrochloride-associated agranulocytosis usually occurs between the fifth and 11th week of therapy and is not related to the total dose of drug received. Three of the nine patients with thioridazine-hydrochloride-associated agranulocytosis have died from infectious complications. Thus, careful monitoring for infection and prompt therapy are indicated.

Aged↗
PubMed1976

Complications with heparin-lock needles. A prospective evaluation.

Because the frequency of complications related to heparin-lock needle usage is unknown, 221 heparin-lock needle insertions in 78 patients were observed for the development of complications. Upon removal of 119 heparin-lock needles from 42 patients, specimens were obtained for culture. Phlebitis was associated with 27 (12%) heparin-lock needle insertions. Only a positive flush culture of the heparin-lock needle system correlated with the development of phlebitis. Phlebitis developed during the first 4 days after heparin-lock needle insertion in two instances and later than 4 days after insertion in 25 instances. All positive flush cultures were obtained from heparin-lock needles in use for longer than 4 days. No patient developed clinically apparent systemic infection. These data suggest that heparin-lock needles should not be used for more than 4 days because, after 4 days of use, there is a significant risk of developing phlebitis, a lesser risk of developing contamination of the infusate in the heparin-lock needle system, and a potential risk of developing nosocomial infection.

Bacteria↗
PubMed1975

Acute codeine overdose: correspondence between clinical course and codeine metabolism.

A patient presented with clinical features of drug overdose. Although heroin was suspected, codeine was identified by drug analysis. The clinical course was complicated by shock, respiratory arrest and laboratory evidence of acute hepatic insufficiency. An inital slow rate of codeine metaboism, possibly related to the hepatic damage, corresponded to prolonged respiratory depression.

Adult↗
PubMedDate not supplied

Same-day versus staged anterior-posterior spinal surgery in a neuromuscular scoliosis population: the evaluation of medical complications.

The medical complications occurring in 29 patients with neuromuscular spinal deformity undergoing two-stage anterior-posterior spinal fusion ("staged") were compared with 16 neuromuscular patients undergoing single-stage anterior-posterior spinal fusion ("same day"). Thirty-six (124%) major and minor medical complications occurred postoperatively in the staged patients, whereas 14 (88%) major or minor complication were present in same-day surgery patients. Thirty-five percent of staged patients had no complications, whereas 63% of same-day patients were without complications. Associated findings comparing the two-stage procedure to the single-stage surgery included operative and anesthesia time increase, increased blood-volume loss, increased blood transfusion, decreased nutritional parameters, and longer hospital stays. With either approach, there is the risk of significant complications in this vulnerable population.

Adolescent↗
PubMedDate not supplied

A mechanistic classification of closed, indirect fractures and dislocations of the lower cervical spine.

Closed, indirect fractures and dislocations of the lower cervical spine occur in families or groups within which there is a spectrum of anatomic damage to a cervical motion segment. This study of 165 cases demonstrates the various spectra of injury, called phylogenies, and develops a classification based on the mechanism of injury. The common groups are compressive flexion, vertical compression, distractive flexion, compressive extension, distractive extension, and lateral flexion. The probability of an associated neurologic lesion relates directly to the type and severity of cervical spine injury. With use of the classification, it is possible to formulate a rational treatment plan for injuries to the cervical spine.

Adolescent↗