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Biomedical subjects

M C Moran

Publications and source records attributed to M C Moran.

At least 19 recordsLinked to original sources
PubMed2000

Behavioral, neurochemical and endocrinological characterization of the early social isolation syndrome.

Rearing rats in isolation has been shown to be a relevant paradigm for studying early life stress and understanding the genesis of depression and related affective disorders. Recent studies from our laboratory point to the relevance of studying the social isolation syndrome as a function of home caging conditions. Accordingly, the present series of experiments assessed the contribution of each condition to the expression of the prepulse inhibition of the acoustic startle, food hoarding and spontaneous locomotor activity. In addition, ex vivo neurochemical changes in the brains of isolated and grouped rats reared either in sawdust-lined or in grid-floor cages were determined by measuring dopamine and serotonin as well as their major metabolites in a "psychosis circuit" that includes mainly the hippocampus and selected hippocampal efferent pathways projecting towards the anterior cingulate and infralimbic cortices, nucleus accumbens, dorsolateral caudate nucleus, amygdala and entorhinal cortex. The results of the present study demonstrate that rearing rats in isolation (i) produces a syndrome of generalized locomotor hyperactivity; (ii) increases the startle response; (iii) impairs prepulse inhibition; (iv) tends to increase food hoarding behavior; (v) increases basal dopamine turnover in the amygdaloid complex; (vi) decreases basal dopamine turnover in the infralimbic part of the medial prefrontal cortex; and (vii) decreases basal turnover of serotonin in the nucleus accumbens. In the entorhinal cortex, dopamine neurotransmission seemed to be more sensitive to the caging conditions since a decreased basal turnover of dopamine was observed in grid-reared animals. Plasma corticosterone levels were also increased in grid-reared animals compared with rats reared in sawdust cages. Finally, isolates reared on grids showed a significant positive correlation between plasma corticosterone levels and dopamine in the left nucleus accumbens.Altogether, these results support the contention that there is a link between social isolation, attention deficit, spontaneous locomotor hyperactivity and reduced dopamine turnover in the medial prefrontal cortex. Furthermore, our data demonstrate that rearing rats in grid-floor cages represents a form of chronic mild stress associated with increased corticosterone levels, decreased basal turnover of entorhinal dopamine and increased dopamine activity in the left nucleus accumbens. Finally, a significant and selective decrease in the basal turnover of serotonin in the nucleus accumbens of isolated rats may be linked to the isolation-induced locomotor hyperactivity.

Acoustic Stimulation↗
PubMed1997

Modified lateral approach to the distal humerus for internal fixation.

Internal fixation of fractures of the most distal portion of the humeral shaft is problematic. A modified lateral approach was assessed to determine its role in the surgical management of these injuries. Posterior plating of the lateral column was performed in each case. Eight patients with eight fractures (seven acute, one nonunion) were treated. All fractures united. There were no complications. On the basis of these results, displaced fractures of the most distal portion of the humeral shaft can be managed successfully via a modified lateral approach to the distal humerus.

Adolescent↗
PubMed1996

Treatment of periprosthetic fractures around total hip arthroplasty with an extensively coated femoral component.

Late periprosthetic fractures may occur around loose cemented femoral components, usually as a consequence of osteolytic bone deficiency. The management of these fractures should include revision total hip arthroplasty using techniques that achieve fracture healing and component stability. If a cementless component is to be used, osseointegration is desirable. Presented herein is a technique of revision total hip arthroplasty for this injury using a curved, extensively coated femoral component. Four cases have been followed for a minimum of 2 years. Each case achieved a good or excellent clinical outcome while radiographs demonstrated fracture healing and osseointegration.

Aged↗
PubMed1996

Functional loss after total knee arthroplasty for poliomyelitis.

Recurvatum deformity secondary to poliomyelitis was corrected during total knee arthroplasty. Modular distal augmentation of the femoral component was successful in achieving and maintaining correction. This case also shows the potential functional disadvantages of correcting recurvatum in patients with quadriceps weakness.

Aged↗
PubMed1996

Supracondylar femoral fracture following total knee arthroplasty.

Twenty-nine supracondylar femoral fractures above total knee arthroplasty were studied retrospectively. Group 1 consisted of 5 nondisplaced fractures managed with closed treatment, yielding 5 satisfactory results. Group 2 consisted of 9 displaced fractures managed with closed treatment. There were no satisfactory results in Group 2; there were 8 malunions and 2 knees requiring revision. Group 3 consisted of 15 displaced fractures managed with open reduction and internal fixation. There were 10 satisfactory results in Group 3; there were 2 malunions and 3 knees requiring revision or repeat fixation. On the basis of these results, closed treatment for nondisplaced fractures is recommended. If displacement exists, early open reduction and internal fixation yields the greatest chance for a satisfactory result, though it has a significant complication rate.

Aged↗
PubMed1996

An assessment of host resistance to ticks on cross-bred cattle in Burundi.

Groups of cattle of four different cross-breeds (Ankole x Friesian, Ankole x Brown-Swiss, Ankole x Guernsey, Ankole x Sahiwal) plus a group of pure Ankole cattle were immunized against tick-borne diseases: East Coast Fever, using a Theileria parva trivalent vaccine, and anaplasmosis, babesiosis and, subsequently, heartwater. With the exception of two small subgroups of Ankole and Ankole x Sahiwal which were treated by weekly spraying using Delnav, all the groups were exposed to natural field challenge of ticks to quantify the development of host resistance to ticks. The results indicate resistance to the most abundant species, Rhipicephalus appendiculatus, as follows: Ankole > Ankole x Sahiwal > Ankole x Brown Swiss > Ankole x Friesian > Ankole x Guernsey. In both Amblyomma variegatum and Rhipicephalus evertsi evertsi, the manifestation of different levels of resistance between breeds is inapparent. Correlations between total ticks and standard female ticks were good for R.appendiculatus (r = 0.73) and R.evertsi (r = 0.51) but poor for A.variegatum (r = 0.31). Correlations between species were reasonably consistent (r = 0.43-0.59). There was no significant correlation between tick burdens and daily liveweight gain (DLWG) over the whole period of the study. Of the cross-bred groups, Ankole x Sahiwal, which had the highest level of resistance, had the highest DLWG. In contrast, the Ankole x Guernsey which developed the lowest level of resistance had only marginally lower DLWG, the difference being only 8 g/day. During the first period of exposure to ticks, however, the untreated Ankole x Sahiwal group had markedly lower DLWG, which may indicate that the development and manifestation of resistance is at the expense of productivity.

Animals↗
PubMed1995

Postoperative fracture of the host femur in allograft-prosthetic reconstruction of the hip.

Massive allograft-prosthetic reconstruction of the proximal femur during revision total hip arthroplasty has yielded successful early results in cases of severe bone deficiency; however, recommendations differ as to the type of prosthesis to be employed and the method of achieving rigid fixation of the allograft. In regard to the bony configuration at the allograft-host junction, a step-cut osteotomy, a transverse osteotomy, and an oblique osteotomy have all been reported. A case is presented in which fracture of the host femur occurred distal to a step-cut osteotomy in osteoporotic bone.

Bone Transplantation↗
PubMed1995

Iatrogenic femoral neck fracture in transient osteoporosis of the hip. A case report.

The diagnostic evaluation of suspected cases of transient osteoporosis of the hip does not typically include biopsy. Presented herein is a case in which an open biopsy procedure was undertaken in the presence of severe osteopenia. An iatrogenic fracture occurred during the surgical exposure. The fracture healed and the condition subsequently resolved. This complication suggests the importance of noninvasive diagnostic modalities in the assessment of this condition. The fragility of the proximal femur also suggests a potential role for a period of protected weight bearing in the management of transient osteoporosis of the hip.

Adult↗
PubMed1995

Distal interlocking during intramedullary nailing of the humerus.

Distal interlocking of intramedullary humeral nails with current systems is performed from either the anterior or lateral approach. To evaluate the potential complications and difficulties of the lateral approach, the author's early experience with this technique in 14 patients was reviewed. In 13 patients, distal interlocking was performing without difficulty using a nailmounted targeting device. In 1 patient early in the series, an iatrogenic injury to the posterior antebrachial cutaneous nerve occurred and a screw missed its distal interlocking hole. No radial nerve injuries occurred. There were no malunions or nonunions. Distal interlocking using a lateral approach requires a careful open surgical technique to avoid nerve injury. In addition, the lateral cortex must be visualized to facilitate accurate drilling and screw insertion.

Adult↗
PubMed1995

Osteonecrosis of the hip in sickle cell hemoglobinopathy.

Osteonecrosis secondary to sickle cell anemia and its genetic variants has many presentations depending on the age of onset and the extent of femoral head involvement. Total hip arthroplasty provides the greatest opportunity for clinical improvement of all treatment options, though early and late complication rates are high. Technical difficulties of total hip arthroplasty are related to marrow hyperplasia and the presence of sclerotic intramedullary bone. Surgical complications related to sickle cell hemoglobinopathy include vaso-occlusive crises, congestive heart failure, major transfusion reactions, intraoperative femoral fracture, femoral perforation, late aseptic loosening of acetabular and femoral components, and sepsis.

Adolescent↗
PubMed1993

Total hip arthroplasty in sickle cell hemoglobinopathy.

Twenty-two arthroplasties were performed in 14 patients with sickle cell hemoglobinopathy (SCH). There were 15 primary and seven revision procedures; none were lost to follow-up evaluation. In the primary arthroplasty group, there were two deaths in patients whose implants were functioning well. The remaining 13 hips had a mean follow-up period of 4.8 years. Failure occurred in five of these 13 hips (38%), four due to aseptic acetabular loosening and one due to sepsis. In the revision arthroplasty group, at a mean follow-up period of 5.3 years, failure occurred in three hips (43%), one due to acetabular loosening, one due to femoral loosening, and one due to sepsis. Perioperative complication rates were high in both groups. Femoral intramedullary sclerosis and bone altered by marrow hyperplasia were associated with intraoperative technical difficulties as well as problems with achieving long-term component fixation. Though total hip arthroplasty provides the most reliable measure of effective treatment in SCH, it carries a high risk of complications and failure.

Adolescent↗
PubMed1990

Strategic tick control in Burundi.

Strategic tick control is an attempt to control ticks and reduce losses in animal production due to tick infestations while decreasing the cost for this control. Tick control is understood as a necessity to achieve maximum animal production from animals raised in tick-infested areas. At the same time, it has become difficult to justify intensive, year-round tick control for local breeds and their crosses. The increasing costs of acaricides, maintenance of the infrastructures, salaries for personnel, etc. have created a tick control programme where the benefits may not be adequate to justify the expense. This has been the case in Burundi. This programme with adequate participation from the cattle owners of Burundi and organizational support from government personnel can help solve this economic problem. The strategic programme reduces the period of tick control to four months each year. Once optimal participation is achieved, this period can probably be reduced to three months (Kaiser et al., 1988). The period of treatment corresponds to when there is maximal feeding activity of adult female ticks on the bovine population within a certain region. Cattle should be treated once each week throughout the four-month period in order to prevent female tick engorgement (based on the life cycle of R. appendiculatus). This will greatly reduce the number of female ticks which are available to recycle the population of ticks in the participating area. At the same time, a certain population of ticks must be maintained in order to assure contact between the cattle, ticks, and tick-borne diseases of this particular region.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Mechanisms of failure of the femoral and tibial components in total knee arthroplasty.

From 1974 to 1986, 1430 cemented primary total knee arthroplasties were available for analysis. These included 224 total condylar prostheses with a polyethylene tibial component, 289 posterior stabilized prostheses with a polyethylene tibial component, and 917 posterior stabilized prostheses with a metal-backed tibial component. There were 12 failures in the total condylar series including three infections (one early and two late), five loose tibial components, two loose femoral and tibial components, and two unstable arthroplasties. The posterior stabilized prosthesis with the polyethylene tibia demonstrated six failures including two loose tibial components, two loose femoral components, and one supracondylar femur fracture. The posterior stabilized prosthesis with the metal-backed tibial component was associated with seven failures including six infections (three early and three late) and one femoral loosening. No metal-backed tibial components have been revised for loosening. The overall failure rate in this series was 1.7% for all prostheses. The incidence of tibial loosening was 0.53% with an average time to failure of 4.7 years. The incidence of femoral loosening was 0.35% with an average time to failure of 2.0 years. Tibial loosening was related to error in technique: postoperative varus tibiofemoral alignment, varus tibial component position, and excessive tibial resection. The overall infection rate was 0.63% for all total knee arthroplasties, and all were secondary to gram-positive organisms. Presently, the posterior stabilized prosthesis with a metal-backed tibia is the authors' implant of choice. Technical error and infection are the major causes of failure.

Aged↗