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Biomedical subjects

J W Martin

Publications and source records attributed to J W Martin.

At least 91 records · Page 5Linked to original sources
PubMed1987

Influence of polycythemia on blood volume and thermoregulation during exercise-heat stress.

We studied the effects of autologous erythrocyte infusion on blood volume and thermoregulation during exercise in the heat. By use of a double-blind design, nine unacclimated male subjects were infused with either 600 ml of a NaCl-glucose-phosphate solution containing a approximately 50% hematocrit (n = 6, reinfusion) or 600 ml of this solution only (n = 3, saline). A heat stress test (HST) was attempted approximately 2-wk pre- and 48-h postinfusion during the late spring months. After 30 min of rest in a 20 degrees C antechamber, the HST consisted of a 120-min exposure (2 repeats of 15 min rest and 45 min treadmill walking) in a hot (35 degrees C, 45% rh) environment while euhydrated. Erythrocyte volume (RCV, 51Cr) and plasma volume (PV, 125I) were measured 24 h before each HST, and maximal O2 uptake (VO2max) was measured 24 h after each HST. Generally, no significant effects were found for the saline group. For the reinfusion group, RCV (11%, P less than 0.01) and VO2max (11%, P less than 0.05) increased after infusion, and the following observations were made: 1) the increased RCV was associated with a reduction in PV to maintain the same blood volume as during the preinfusion measurements; 2) polycythemia reduced total circulating protein but did not alter F-cell ratio, plasma osmolality, plasma protein content, or plasma lactate at rest or during exercise-heat stress; 3) polycythemia did not change the volume of fluid entering the intravascular space from rest to exercise-heat stress; and 4) polycythemia tended to reduce the rate of heat storage during exercise-heat stress.

Blood Proteins↗
PubMed1987

Elite special forces: physiological description and ergogenic influence of blood reinfusion.

We measured the physical exercise capabilities of U.S. Army Special Forces soldiers (male) and determined the subsequent ergogenic influence of autologous blood reinfusion. Twelve subjects (Ss) completed maximal exercise treadmill testing in a comfortable (Ta = 20 degrees C, Tdp = 9 degrees C) environment. Six Ss were later transfused with a 600 ml autologous red blood cell (50% Hct) NaCl glucose-phosphate solution and completed identical maximal exercise tests 3 and 10 d posttransfusion. Pretransfusion, the 12 Ss had a maximal oxygen uptake (VO2max) of 4.36 +/- 0.56 L . min-1 and 55 +/- 4 ml . kg-1 . min-1 with a heart rate of 188 +/- 10 b . min-1 and ventilatory equivalent for oxygen of 37 +/- 3. For the 6 reinfused Ss, hemoglobin and red cell volume (RCV) increased by 10% (p less than 0.05) and 11% (p less than 0.05), respectively, posttransfusion. Reinfusion increased (p less than 0.05) VO2max from 4.28 +/- 0.22 L . min-1 (54 +/- 5 ml . kg-1 . min-1) to 4.75 +/- 0.42 L . min-1 (60 +/- 6 ml . kg-1 . min-1) and 4.63 +/- 0.21 L . min-1 (59 +/- 6 ml . kg-1 . min-1) at 3 and 10 d posttransfusion, respectively. No significant relationship was found between the individual change in RCV and VO2max values pre- to posttransfusion. We conclude that Special Forces soldiers have high levels of aerobic fitness that can be further increased by blood reinfusion for at least 10 d.

Adult↗
PubMed1986

Organization of sensory neurons to the muscles of mastication in the cat.

The sensory neurons in the trigeminal ganglion which project to the muscles of mastication of the cat were studied using the retrograde transport of horseradish peroxidase. Horseradish peroxidase either was injected directly into the masticatory muscles or applied to the nerves supplying them. Numerous retrogradely labeled neurons were found in the ipsilateral trigeminal ganglion. All labeled neurons were sequestered within the posterolateral (mandibular) portion of the ganglion, but the ganglion cells innervating individual muscles were not organized topographically. The diameter of the labeled neurons varied greatly and included profiles considered small, medium and large. The organization of the neurons in the trigeminal mesencephalic and trigeminal motor nuclei which project to individual masticatory muscles also was noted. It is suggested that many of the ganglion cells of small and medium size may be important for the perception of muscle pain from the masticatory muscles in the cat.

Animals↗
PubMed1986

Metallurgical analysis of failed Björk-Shiley cardiac valve prostheses.

An investigation into the mechanisms of failure of current Björk-Shiley cardiac valve prostheses is reported. Two failed valves, one apparently unfailed but defective valve, and one unused valve, were examined by scanning electron microscopy and metallographic section. In the first two valves (removed 12 and 23 months after implantation) fracture was associated with the welds joining the short strut to the valve ring. The fracture surfaces in all cases were heavily faceted and showed branching cracks. Extensive wear had occurred on one fracture surface in the first case, suggesting that one leg of the short strut had failed before the other, though this had been clinically undetectable. The third valve was removed owing to failure of the suturing (24 months after implantation) but one leg of the short strut was found to be completely fractured. The other leg showed extensive cracking and porosity in the weld region. A metallographic section taken through the weld region of the fourth (unused) valve illustrated several sizable defects directly attributable to the welding process. It is suggested that the valves failed by fatigue and that these problems could be overcome if the complete valve cage were machined as a single piece.

Aged↗
PubMed1986

Achilles tendon rupture. Occurrence with a closed ankle fracture.

A 61-year-old man, involved in an automobile accident, sustained a complete Achilles tendon rupture with an ipsilateral, closed slightly displaced medial malleolus ankle fracture. The tendon rupture was not diagnosed before operation but was recognized at the time of open reduction of the ankle. This rare combination of injuries was apparently secondary to hyperdorsiflexion of the foot. The tendon rupture would have been missed had surgical treatment not been required. Unrecognized tendon ruptures associated with closed ankle fractures may be a cause of residual ankle-foot weakness, pain, loss of motion, or a combination thereof.

Achilles Tendon↗
PubMed1985

Hollow obturator with removable lid.

Hollowing the obturator reduces the weight of the prosthesis. Closed and open hollow obturator prosthesis each have their particular benefits. However, the obturator with a removable lid has its benefits also, and the advantages have been described.

Humans↗
PubMed1984

Skin grafts in intraoral reconstruction. A new stenting method.

The results of skin graft reconstruction in intraoral cancer in 65 consecutive cases were uniformly good. There were only 11 wound complications and all resolved spontaneously without additional surgery. Skin grafts were used successfully in conjunction with coronal resections of the mandible, incontinuity modified neck dissections, and composite resections. Postoperative radiation therapy had no ill effects on the grafts or oral hygiene. A new stenting method with a dental tissue conditioner was employed. When used to immobilize intraoral skin grafts, it improved oral hygiene and patient deglutition, thereby hastening rehabilitation. The success of grafts performed with the new stent was equal to (if not better than) the success of grafts performed with the traditional stent.

Adult↗
PubMed1984

Surgical stents for the head and neck cancer patient.

Split-thickness skin graft reconstruction following intraoral cancer surgery maintains functional mobility within the oral cavity and gives excellent support for the final intraoral rehabilitative prosthesis. We describe the use of a dental material, called tissue conditioner, for skin graft immobilization as an alternative to the usual gauze bolus and thermoplastic materials following surgery in various intraoral anatomic sites.

Dentures↗
PubMed1984

Cranial implant modification.

This technique combines the heat-cured resin system with an autopolymerizing resin system (Cranioplast). Cranioplast has been used since the early 1950s. Clinical trials have shown that it evoked the least severe inflammatory response when compared with other autopolymerizing methyl methacrylate systems. The advantage inherent in this technique is the ability to go to the operating room with a prefabricated heat-cured acrylic resin prosthesis and alter the implant with Cranioplast for excellent adaptation to the defect. The technique provides a well-fitting cranial implant prosthesis with good cosmetic results.

Acrylic Resins↗
PubMed1983

Cast circumferential and wire clasps for obturator retention.

The indications and rationale for using cast circumferential and wire clasps for obtaining retention of obturator prostheses have been presented and discussed. Only the test of time can prove the effectiveness of an obturator design. The infinite variability of physical and patient factors demands understanding and application of basic fundamentals and, in the final analysis, good clinical judgment. Clasping is only one part of the obturator, and it must fit harmoniously into the overall design of the prosthesis. How the clasp contributes to support and bracing as well as retention must always be considered.

Denture Retention↗
PubMed1983

Prosthodontic care of patients receiving chemotherapy and irradiation to the head and neck.

The basic requirements for successful dental prostheses must be applied to the particular needs of patients receiving chemotherapy or irradiation to the head and neck. The compromised tissue integrity of these patients dictates that added emphasis be placed on meeting these requirements. The objective is to ensure that the patient will not be traumatized by, or become septic as a result of, his prostheses or dental condition. In this chapter we have emphasized care of removable prostheses, but it is equally important to examine and repair or remove faulty fixed prostheses and restorations.

Dental Occlusion↗