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Biomedical subjects

J R Kirkpatrick

Publications and source records attributed to J R Kirkpatrick.

At least 55 records · Page 3Linked to original sources
PubMed1979

Effects of adenosine and adenine nucleotides on synaptic transmission in the cerebral cortex.

Adenosine and the adenine nucleotides have a potent depressant action on cerebral cortical neurons, including identified corticospinal cells. Other purine and pyrimidine nucleotides were either weakly depressant (inosine and guanosine derivatives) or largely inactive (xanthine, cytidine, thymidine, uridine derivatives). The 5'-triphosphates and to a lesser extent the 5'-diphosphates of all the purine and pyrimidines tested had excitant actions on cortical neurons. Adenosine transport blockers and deaminase inhibitors depressed the firing of cortical neurons and potentiated the depressant actions of adenosine and the adenine nucleotides. Methylxanthines (theophylline, caffeine, and isobutylmethylxanthine) antagonized the depressant effects of adenosine and the adenine nucleotides and enhanced the spontaneous firing rate of cerebral cortical neurons. Intracellular recordings showed that adenosine 5'-monophosphate hyperpolarizes cerebral cortical neurons and suppresses spontaneous and evoked excitatory postsynaptic potentials in the absence of any pronounced alterations in membrane resistance or of the threshold for action potential generation. It is suggested that adenosine depresses spontaneous and evoked activity by inhibiting the release of transmitter from presynaptic nerve terminals. Furthermore, the depressant effects of potentiators and excitant effects of antagonists of adenosine on neuronal firing are consistent with the hypothesis that cortical neurons are subject to control by endogenously released purines.

1-Methyl-3-isobutylxanthine↗
PubMed1978

Vasoactive intestinal polypeptide excitation of central neurons.

Vasoactive intestinal polypeptide (VIP) was tested on neurons in the rat sensory motor cerebral cortex and on the isolated hemisected toad spinal cord. Iontophoretically applied VIP excited deep, spontaneously active cortical neurons, including identified corticospinal neurons. The excitation had a latency of onset varying from several seconds to over 1 min and often lasted for a minute or longer after cessation of the application. Desensitization of the effect occurred with repeated applications. VIP caused a depolarization of motoneurons and dorsal root terminals in the isolated amphibian spinal cord. Threshold for this effect was about 10(-6) M. The effects of VIP on both preparations were comparable with those of another peptide, substance P.

Acetylcholine↗
PubMed1977

Selective hyperalimentation: a new look at an old problem.

Safe and consistently reliable parenteral hyperalimentation in the care of the critically ill or injured remains an unrealized expectation. Our experience with critically ill patients managed with standard 25% dextrose/4.25% protein hyperalimentation solution (S.H.A.) delivered through a centrally placed catheter demonstrated that S.H.A. was associated with a high catheter infection rate, fluctuations in hyperosmolar tolerance, unstable insulin requirements, and a high discontinuation rate. In retrospect this unsatisfactory experience resulted from the inappropriate assumption that a single type of nutritional support and delivery system could meet the varying metabolic requirements of the critically ill or injured. In an effort to reduce these complications, we have recently utilized a system of selective hyperalimentation in managing 25 consecutive patients. We now identify specific risk factors for groups of patients and use these factors to select the appropriate rout and solution. Selective hyperalimentation has resulted in a lowering of infusion complications and an improvement in completion rate, with satisfactory weight gain and protein response. These results suggest that our approach is sucessful in meeting the nutritional requirements of differing groups of critically ill patients without exposing upsuitable candidates to the potential risks of standard hyperalimentation.

Adolescent↗
PubMed1977

The exteriorized anastomosis: its role in surgery of the colon.

Sixty-one patients (59, trauma; two, nontrauma) have been managed at Detroit General Hospital from 1972 to 1976 utilizing an exteriorized colon anastomosis. Healing of the anastomosis was present in 42 (70%) of the patients, and 37 (62%) avoided colostomy. Our experience with this procedure has demonstrated that it is a safe, reliable adjunct to be used in colon surgery when primary intraperitoneal repair is not desirable, that the added operating time (20 to 30 minutes) will not be deleterious to the patient, that the lesion is at least 18 cm above the peritoneal reflection, and that the likelihood of a prolonged septic postoperative course is not high.

Colon↗
PubMed1975

Needle aspiration of breast cysts.

A total of 149 breast cysts have been treated with primary aspiration. Findings were abnormal in 36 patients, 30 of whom underwent excision of the breast cyst with cancer being found in four. Careful examination of the breast after aspiration and follow-up are necessary, but, provided these precautions are observed, this type of treatment is simple, safe, and cheap besides often giving the patient relief at the first consultation.

Adult↗
PubMed1975

The role of definitive surgery in the management of perforated duodenal ulcer disease.

From 1970 to 1973, 147 patients were treated at Wayne State University Affiliated Hospitals for perforated duodenal ulcer disease. One hundred thirteen were observed for at least 18 months and findings showed that (1) mortality was dependent on the condition of the patient rather than on the choice of operation, (2) current indications (previous ulcer history, degree of peritoneal contamination, and time interval between performation and surgery) were not reliable in choosing the initial operation or in predicting the need for subsequent surgery, and (3) morbidity was high following simple closure. Therefore, we recommend vagotomy and pyloroplasty as the procedure of choice for a perforated duodenal ulcer, unless the patient is in septic shock at admission.

Adult↗
PubMed1975

The injured colon: therapeutic considerations.

A prospective randomized study was carried out at the Detroit General Hospital over a two year period to evaluate methods of management in 165 patients with colonic injuries. Results of the study show that primary closure is a safe and reiable method of management when rigid criteria are incorporated in an ongoing protocol. Moreover, the technic of exteriorization is a safe adjunct to management and is recommended in any patient with a colonic injury above 18 cm in which one suture line is required and in which the additional operating time of twenty minutes will not compromise the management of secondary injuries. Patients not fulfilling these criteria should have primary colostomy. These principles make it possible to reduce the need for primary colostomy to approximately 50 per cent in a large ongoing group of patients with colonic injury.

Abdominal Injuries↗