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Biomedical subjects

R McKenzie

Publications and source records attributed to R McKenzie.

At least 91 records · Page 5Linked to original sources
PubMed1982

Effects of glutaraldehyde fixative osmolarities on smooth muscle cell volume, and osmotic reactivity of the cells after fixation.

The contribution of glutaraldehyde (GA) to the effective osmolarity of GA fixatives, the osmotic reactivity of the cells after fixation in GA, and also the duration of fixation in GA on cell volume, were investigated using cultured smooth muscle cells (SMC) and spiral aortic strips. Four fixation procedures were studied. We found that GA contributes to the total effective osmolarity of the fixatives, and that the type of buffers used for the fixatives can also affect the cell volume differently during GA fixation. After GA fixation, the cells were still osmotically reactive, regardless of the buffer types for making up the GA fixatives, so that the osmolarity of the wash buffer after GA fixation is important. However, OsO4 eliminates osmotic responses, thus the osmolarity of OsO4 fixative and wash buffer have negligible influence on the cell volume. Longer fixation time up to 4 h had no effect of the cell volume.

Aldehydes↗
PubMed1981

Antiemetic effectiveness of intramuscular hydroxyzine compared with intramuscular droperidol.

In a double-blind randomized study 150 outpatients receivng the same anesthetic for first trimester therapeutic abortions were equally divided into three groups: control; droperidol, 2.5 mg IM; or hydroxyzine, 100 mg IM. The injection was given immediately after thiamylal (Surital) induction of anesthesia, and the incidence of nausea, retching, or vomiting (NRV) was recorded at 15-minute intervals for 3 hours after surgery. NRV occurred in 56% of control patients, in 44% of patients given droperidol, and in 10% of patients given hydroxyzine. The patients receiving hydroxyzine and droperidol were more sedated and experienced a delay in return of hand-eye coordination as measured by the time for the Trieger motor test to reach preoperative levels. All patients equaled their preoperative performance during the 3rd hour after surgery and were discharged 4 hours following general anesthesia. We conclude that intramuscular hydroxyzine hydrochloride, 100 mg, is a significantly better antiemetic than intramuscular droperidol, 2.5 mg.

Abortion, Induced↗
PubMed1980

Noninvasive measurement of cardiac output during laparoscopy.

With the use of noninvasive transthoracic impedance cardiography we have demonstrated a consistent fall in stroke volume and cardiac output without significant clinical changes in heart rate in anesthetized patients undergoing laparoscopy. Cardiac output fell to a mean value of 60% in 14 patients undergoing laparoscopy and by a mean value of 6% in four patients undergoing laparotomy. The intraabdominal pressure did not exceed 20 torr in any laparoscopy patient. Some unexplained cardiac arrests during laparoscopy in healthy females may be caused by impaired venous return due to the increased intraabdominal pressure of pneumoperitoneum. Lethal values of cardiac output could result. The routine use of transthoracic impedance cardiography would alert the anesthesiologist to a dangerous situation that cannot be determined by current routine monitoring practice.

Abdomen↗
PubMed1978

A safer method for paracervical block in therapeutic abortions.

Adverse reactions to paracervical block, including death, are believed to be dose related. By using a modified jet injector instead of the standard syringe-and-needle technique, we obtained equal analgesia with one fifth of the standard milligram dosage of lidocaine in patients undergoing therapeutic abortion. Blood lidocaine levels as determined by gas chromatography were reduced by two thirds with jet injection. These results led us to conclude that jet injection for paracervical block is safer than the syringe-and-needle technique.

Abortion, Therapeutic↗
PubMed1977

Anaesthesia for dilatation, evacuation and curettage in outpatients: comparison of subanaesthetic doses of ketamine and sodium methohexitone-nitrous oxide anaesthesia.

Sub-dissociative doses of ketamine compared unfavourably with methohexitonenitrous oxide anaesthesia for dilatation, evacuation and curettage. We could not separate the desirable effects of analgesia and amnesia from the unwanted dream effects and visual disturbances. Although the time of clinical recovery was similar, the Trieger Motor Test revealed a delay in return to normal in both groups.

Adolescent↗
PubMed1977

Ketamine as the sole anaesthetic agent for laparoscopic sterilization. The effects of premedication on the frequency of adverse clinical reactions.

Ketamine, as the sole anaesthetic agent, was assessed in a double-blind study of 135 female patients who underwent laparoscopic sterilization. The patients were allocated randomly to one of four groups according to the type (pentobarbitone or droperidol) and route (i.v. or i.m.) of premedication. In addition all the patients received hyoscine i.m. Neither pentobarbitone nor droperidol prevented adverse emergence reactions and the total frequency of dream-like activity. However, patients who received pentobarbitone i.v. did not recall unpleasant dream-like activity. Patients who received droperidol i.v. had the shortest recovery time after ketamine anaesthesia. There was a high incidence of visual disturbances in all groups. Droperidol protected against the initial increase of heart rate, and pentobarbitone against the increase in arterial systolic pressure associated with ketamine.

Adult↗
PubMed1976

Dissociation of urate from sodium transport in the rat proximal tubule.=.

The tubular transport of urate and sodium was examined by clearance, free-flow micropuncture, intratubular microinjection and precession techniques in control rats and in rats receiving a new uricosuric diuretic, indanyloxyacetic acid (MK-196). The i.v. infusion of MK-196 (50 mg/kg of body wt/hr) resulted in significant increases in the fractional excretion of sodium (FENa) from 0.98 +/- 0.01 to 11.86 +/- 2.88% (P less than 0.001) and in FEurate from 14.1 +/- 1.03 to 56.0 +/- 2.86% (P less than 0.001). End-proximal tubular fluid to plasma inulin (TF/Pinulin) ratios were 2.43 +/- 0.15 and 2.51 +/- 0.10 in control and drug-treated animals, respectively (P = NS). Total urinary urate recovery after MK-196 administration was higher following microinjections of [2-14C] urate into early proximal tubule sites: 70.5 +/- 2.7% in controls vs. 84.9 +/- 0.9 (P less than 0.001), and after microinjections into late proximal tubule sites: 82.8 +/- 2.9% vs. 91.3 +/- 1.9 (P less than 0.05). Urinary precession of urate from inulin was demonstrable following placement of isotopes of these compounds on the surface of the kidney in controls, but was abolished by MK-196. This agent, therefore, inhibits the reabsorption and secretion of urate in the proximal convoluted tubule, the net effect being a marked increase in urinary urate excretion. By contrast, its inhibitory effect on sodium reabsorption is exerted at a site or sites distal to the accessible portion of the proximal tubule. The demonstration of reduced urate reabsorption and normal sodium reabsorption in the proximal tubule suggests that the reabsorption of these constituents of the glomerular filtrate is not intimately linked at this nephron site.

Animals↗