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Biomedical subjects

C Hamlin

Publications and source records attributed to C Hamlin.

13 recordsLinked to original sources

Surgical reconstruction in tetraplegia.

The authors reviewed their 10 years of combined experience in the surgical reconstruction of the upper extremities in 170 quadriplegic patients from two spinal cord treatment centers. The authors' current recommendations regarding patient selection are presented, refinements in previously published surgical techniques are defined, and the principles of postoperative care are discussed.

Biomechanical Phenomena

Chronic sesamoiditis of the thumb: pathomechanics and treatment.

Entrapment of the sesamoids within the metacarpophalangeal joint can result in irreducible dislocations; however, dysfunction from trauma-induced, chronic sesamoiditis is unfamiliar. Twenty-five patients with intractable posttraumatic pain of the metacarpophalangeal joint of the thumb are reported. The mechanisms of the palmar plate injury included hyperextension, direct compression, shear forces, and lateral stress. Sesamoidectomy achieved good results in 80% of patients as evidenced by return to preinjury activities. Residual joint stiffness was present in 20% of patients, and 8% had significant residual pain. Traumatic microtears appear to produce pathologic findings in the perisesamoid tendon and/or sesamoid-metacarpal articulation.

Chronic Disease

Compartment syndrome in the upper extremity.

It has been the purpose of this article to assist us in our approach to compartment problems, for, although a full-blown compartment syndrome following forearm injury is statistically uncommon, the results of this ischemic process can be devastating. A compartment pressure of greater than 30 mmHg for eight hours or more can cause cell death by interference with the microcirculation. Clinical diagnosis is made on the basis of a number of modalities, especially pain and paresthesias. Peripheral pulses or capillary flow are not specific indicators of compartment well-being. Direct compartment pressure measurements can be an invaluable tool but must be used in conjunction with the trend of the clinical findings. Limb elevation is not assistive in reducing compartment pressure, although removal of circumferential dressings and maintenance of mean arterial pressure can be. Prompt surgical decompression of the compromised compartment is the treatment of choice.

Arm

Diagnosis of wrist injuries.

There is little in the way of surface architecture to explain the complex anatomy of the wrist. Confidence in x-ray examination, especially the lateral, is essential to primary accurate diagnosis. The primary care physician will have a great impact on the end-result of wrist injuries because late care is difficult and has a guarded prognosis.

Carpal Bones

In vivo biocompatibility studies. I. The cage implant system and a biodegradable hydrogel.

A cage implant system has been utilized to examine the in vivo biocompatibility of a biodegradable hydrogel, poly(2-hydroxy-ethyl-L-glutamine) (PHEG). This system permits the quantitative determination of the components of the inflammatory exudate which surrounds the implanted polymer within the cage system. This system permits the serial examination of exudate components without sacrificing the animal. In addition, this system allows the subsequent removal of the polymer for surface and mechanical studies. Following implantation of the biodegradable hydrogel, quantitative and differential white cell counts of the exudates were determined over a 21-day period. In addition, concomitant extracellular enzyme analyses for alkaline phosphatase, acid phosphatase, prostatic acid phosphatase, leucine amino-peptidase, and Cathepsin B1 were determined. Corresponding control samples from exudates of the cage implant without the polymer were also determined. The two-tailed Student's t-test for unpaired samples was used to statistically compare the control and implanted polymer values for these respective analyses at the various time periods. A comparison of the cellular response for the control system and the PHEG system did not show statistically significant differences during the first 7 days following implantation. The acute inflammatory response, polymorphonuclear leukocyte predominant, was followed by a mild chronic inflammatory response, macrophage and lymphocyte predominant, and during this time period, 8-14 days, macrophages were present in significantly larger numbers for the PHEG system when compared to the control values. Enzymic analysis of the exudates revealed statistically significant differences between control and PHEG values at time intervals where no differences were noted in cell density or population. These results are discussed in terms of cell-polymer interactions leading to cellular activation and enhanced enzyme exocytosis by the inflammatory cells. Stress-strain measurements on implanted PHEG samples showed that significant in vivo degradation had occurred during the acute inflammatory phase of the response, i.e., the first 7 days.

Acid Phosphatase

Neurotransmitters extraction by local intracerebral dialysis in anesthetized rats.

A new technique for in vivo neurotransmitter extraction was developed. Perfusion U shaped cannulae were chronically implanted in the caudate or the thalamus of rats. A segment of the cannula was a piece of dialysis tube of molecular weight cut off 1000. Measurable amounts of dopamine and norepinephrine were recovered from the perfusion fluid. Intraperitoneal amphetamine 10 mg/kg increased dopamine output from the caudate but not from the thalamus. The potential applications of this technique are discussed.

Anesthesia

Relative merits of two electrophoretic and two column-chromatographic kets for determining serum creatine kinase isoenzyme MB activity.

Prospective analysis (by use of commercially available kits) of 339 validated admission specimens from patients consecutively admitted to a cardiac monitoring unit revealed sensitivities of 68 and 63% for two electrophoretic assays (Bioware and Helena) and up to 73 and 77% for two chromatographic assays (Roche and Worthington). Specificities were 94.8, 96,6, 90.2, and 89.7% and efficiencies were 90.2, 90.7, 87.0, and 87.0, respectively. Although these results differ from early reports, they agree well with several recent studies. However, 86 (25%) of the specimens gave at least one discrepant result based on clinical evaluation of the patients, and 68 (20%) gave at least one discrepant result between methods.

Chromatography, Ion Exchange