Biomedical subjects
Publications and source records attributed to J L Hall.
The use of adversarial methods to resolve disputes arising out of medical staff matters can be time-consuming, costly, and disruptive to the hospital-medical staff relationship. As this article suggests, mediation is the preferred method of alternative dispute resolution for reaching mutually acceptable solutions with minimal harm to relationships.
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Adrenoceptor antagonists block the enhancement of memory storage produced by epinephrine injection, but not that produced by glucose injection. The present experiment determined whether adrenoceptor antagonists modify resting blood glucose levels or the magnitude of epinephrine-, glucose-, and footshock-induced increases in circulating glucose levels in a manner related to these previously observed effects on memory. The alpha- and beta-adrenoceptor antagonists, phenoxybenzamine and propranolol, respectively, were injected in rats 30 min prior to administration of epinephrine, glucose, or footshock. Plasma glucose levels were sampled during the next 30 min. Epinephrine-induced increases in plasma glucose levels were potentiated by phenoxybenzamine and were attenuated and delayed by propranolol. The adrenoceptor antagonists did not alter resting plasma glucose levels, or the increases in plasma glucose levels resulting from glucose injection or footshock. These findings suggest that phenoxybenzamine and propranolol alter blood glucose responses to epinephrine injection in a manner which may contribute to attenuation of epinephrine-induced enhancement of memory storage with peripheral injections of adrenoceptor antagonists.
The present studies have evaluated the effects of pharmacologically induced release serotonin on sexual responses of male rats during exposure to a sexually receptive female rat. Following acute administration of fenfluramine or para-chloroamphetamine (PCA), significant dose-related decreases in copulatory rate and copulatory efficiency, and increases in ejaculatory latency were observed. These effects were not observed when the animals were pretreated with LY53857, a 5-HT1c/2 antagonist. These studies indicate that acute release of serotonin evoked by these releasing agents has inhibitory effects on sexual sexual drive, capacity to achieve erection and threshold for ejaculation, and these effects are mediated by either the 5-HT1c or 5-HT2 receptor.
Glucose administration near the time of training or testing elevates blood glucose levels and enhances memory in rodents and humans. The magnitude of increases in circulating glucose levels predicts later retention performance in these and several other situations. Thus, circulating glucose levels appear to contribute to the regulation of memory storage processes. Phlorizin is an inhibitor of glucose transport, which, in view of the effects of glucose on memory, should impair memory. However, rats and mice injected with phlorizin before training in an inhibitory (passive) avoidance task demonstrated significantly enhanced memory performance compared to that of control animals. The effective dose of phlorizin did not significantly change regional brain-relative 3H-2-deoxyglucose uptake or plasma glucose levels. To summarize, phlorizin is a potent memory-enhancing drug. While the mechanism of this enhancement is unknown, it does not appear to include changes in blood glucose levels or brain glucose uptake.
We assessed the relationship between myocardial glucose metabolism and blood flow during ischemia in eight open-chest swine. Coronary flow was controlled by an extracorporeal perfusion circuit. Left anterior descending coronary arterial (LAD) flow was reduced by 60%, while left circumflex flow was normally perfused. The rate of glucose uptake (Rg) was measured with a coronary infusion of 2-deoxy-D-[14C]glucose and myocardial blood flow with radiolabeled microspheres. Myocardial biopsies were taken after 50 min of ischemia. Regional arterial-venous glucose difference was calculated as Rg per myocardial blood flow. Subendocardial blood flow decreased from 1.27 +/- 0.19 to 0.25 +/- 0.11 ml.g-1.min-1 (P less than 0.0001). The subendocardial arterial-venous glucose difference was greater in the LAD bed (1.38 +/- 0.35 mumol/ml) than the left circumflex coronary arterial perfusion bed (0.10 +/- 03; P less than 0.01); however, there was no statistically significant difference in the rate of glucose uptake between the two beds. Subendocardial glycogen concentration in the LAD perfusion bed was reduced to 26% of circumflex bed values. In conclusion, acute ischemia stimulated a dramatic increase in glucose extraction; however, this did not compensate for the decrease in blood flow, and thus the rate of glucose uptake did not increase significantly. The high rate of glycolysis is primarily supported by accelerated net glycogen breakdown rather than increased glucose uptake.
Under the federal patient anti-dumping statute, physicians are required to treat a hospital's emergency patients, including women in labor, and must comply with detailed statutory provisions that govern when it is appropriate to transfer a patient to another facility. A thorough understanding of this law is necessary to minimize the risk of liability to the physician and the hospital. This article, the first of two parts, discusses the requirements under the statute. Part II, which will appear in a future issue, will discuss court interpretations of the statute and its impact on medical malpractice claims.
This is the second part of a two-part article examining the federal patient anti-dumping statute, under which physicians are required to treat a hospital's emergency patients, including women in labor, and to comply with certain requirements that dictate when it is appropriate to transfer a patient. Part I discussed in detail the provisions of the statute. Part II analyzes various court interpretations of the law and its potential impact on physician liability.
In a prospective, randomized study, we compared the ability of ceftriaxone sodium (serum half-life, 8.0 hours) and cefamandole naftate and sodium carbonate (serum half-life, 0.8 hours) to prevent wound infection in 1238 patients undergoing abdominal surgery. Prophylaxis consisted of single-dose therapy at the time of induction of anesthesia, and treatment regimens contained ceftriaxone sodium, 1 g/d intravenously, or cefamandole naftate and sodium carbonate, 1 g intravenously every 6 hours. Except for low-risk biliary procedures, cephalosporin therapy was accompanied by the administration of metronidazole. No significant difference was noted in the incidence of wound infection, ie, 5.6% for the ceftriaxone group (95% confidence interval, 3.8% to 7.4%) and 6.9% for the cefamandole group (95% confidence interval, 4.9% to 8.9%). Single-dose prophylaxis with 1 g of cefamandole naftate and sodium carbonate was relatively inexpensive and provided a cost savings of 64%. When treatment was required, a 23% cost savings was associated with the use of a once-daily dose of 1 g of ceftriaxone sodium.
We evaluated the relationship between PPC and various putative risk factors in a prospective longitudinal study of 1,000 patients undergoing abdominal surgery. Transient subclinical events were excluded by defining PPC as positive clinical findings in combination with either positive sputum microbiology, unexplained pyrexia, or positive chest roentgenographic findings. The overall incidence of PPC was 23.2 percent (232/1,000). Multivariate analysis identified seven factors which were associated with PPC: ASA classification greater than 2, upper abdominal surgery, residual intraperitoneal sepsis, age greater than 59 years, BMI greater than 25, preoperative hospital stay greater than 4 days, and colorectal or gastroduodenal surgery (overall F score = 33.5, p less than 0.0001). The ASA classification was the most powerful indicator of risk in both the univariate and the multivariate analyses. The combination of ASA classification greater than 1 and age greater than 59 years identified 88 percent (205 of 232) of the patients who developed PPC. These findings provide clinicians and clinical investigators with a simple means of identifying patients who are at high risk of PPC after abdominal surgery.
Adjunct use of leuprolide (LA) in patients undergoing controlled ovarian hyperstimulation with human menopausal gonadotropins (hMG) was evaluated by three protocols: Group F (n = 24) began LA on day 2 of the cycle and Group L (n = 38) began LA on day 23 of the cycle until ovarian suppression, at which time hMG was added. Group FL (n = 17) began LA on day 1 and hMG on day 3. Compared to FL, more ova were collected, more ova fertilized, and more pregnancies resulted per initiated cycle in groups achieving suppression before hMG stimulation. Fewer days were necessary to attain suppression for L vs F. After achieving suppression, patients were maintained on either 0.5 mg LA or 0.25 mg LA daily during hMG coadministration with similar results. Lower maintenance doses of LA during hMG did not decrease the amount of hMG needed but retained the benefits of LA. We recommend luteal initiation of LA to achieve suppression before hMG.
Fetal wound healing occurs rapidly and without inflammation, fibrosis, or scar formation. It is a process fundamentally different from adult wound healing. The mechanisms that underlie such unique healing properties are unknown. However, hyaluronic acid, a glycosaminoglycan component of the extracellular matrix, is prominent throughout the course of fetal wound healing, and is thought to play a major role in the healing process. Amniotic fluid contains high levels of hyaluronic acid. Amniotic fluid also contains a number of potent growth factors that are critical for fetal development. In this report, a new factor in amniotic fluid that stimulates deposition of hyaluronic acid is described. This activity is measured in an in vitro assay system in which cultured fibrosarcoma cells are used as indicator cells. Amniotic fluid thus provides two separate mechanisms for the deposition of hyaluronic acid. One is by exogenous application directly onto fetal skin wounds; the second is by providing a factor to increase the production of hyaluronic acid endogenously, by stimulating cells around the wound site. The resulting hyaluronic acid-rich area may support the ability of the fetal wound to heal with its unique properties.
Circulating glucose levels regulate memory storage under several conditions. This study examined the contribution of blood glucose levels to the transient memory impairment seen in adrenalectomized rats. Inhibitory (passive) avoidance retention performance, blood glucose levels, and glycemic responses to footshock were tested 1, 2, and 8 days after adrenalectomy. Adrenalectomized animals demonstrated a transient inhibitory avoidance deficit 1 and 2 days after surgery which recovered by 8 days. The adrenalectomy-induced memory deficit was accompanied by decreased resting blood glucose levels. In animals tested 2 days after adrenalectomy, this decrease in baseline blood glucose levels was exacerbated by further reductions, rather than the normal increases, in circulating glucose levels after training. The magnitude of blood glucose increases after glucose injection was decreased in adrenalectomized animals tested 2 days after surgery. Posttraining glucose injections restored the retention performance of animals trained 2 days after adrenalectomy to that of sham-operated animals. These findings suggest that abnormalities in blood glucose regulation may contribute, in part, to the transient memory impairment seen after adrenalectomy. Additionally, the results further implicate blood glucose in the regulation of CNS information processing systems.
In this paper, a method that has been developed for the assessment and quantification of loudness perception in normal-hearing and hearing-impaired persons is described. The method has been named LGOB, which stands for loudness growth in 1/2-octave bands. The method uses 1/2-octave bands of noise, centered at 0.25, 0.5, 1.0, 2.0, and 4.0 kHz, with subjective levels between a subject's threshold of hearing and the "too loud" level. The noise bands are presented to the subject, randomized over frequency and level, and the subject is asked to respond with a loudness rating (one of: VERY SOFT, SOFT, OK, LOUD, VERY LOUD, TOO LOUD). Subject responses (normal and hearing-impaired) are then compared to the average responses of a group of normal-hearing subjects. This procedure allows one to estimate the subject's loudness growth relative to normals, as a function of frequency and level. The results may be displayed either as isoloudness contours or as recruitment curves. In its present form, the measurements take less than 30 min. The signal presentation and analysis is done using a PC and a PC plug-in board having a digital to analog converter.
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Women being evaluated for infertility were offered assisted reproductive technology at the time of diagnostic laparoscopy. Oocyte retrieval was performed after ovulation induction in 33 women, of whom 19 had concurrent operative laparoscopy. Gamete intrafallopian transfer (GIFT) or in vitro fertilization (IVF) and embryo transfer were performed subsequently depending on laparoscopic assessment of pelvic architecture, oocyte maturity, and semen parameters. The clinical pregnancy rate was 24% per cycle and 28% per gamete or embryo transfer (four pregnancies after GIFT and four after IVF/embryo transfer). The clinical pregnancy rate per transfer did not differ significantly between the 19 women who had therapeutic operations in conjunction with laparoscopy (lysis of adhesions and/or fulguration of endometriosis) and the 13 who did not (25 versus 30%; P greater than .05). Assisted reproductive technology can be performed successfully during diagnostic infertility laparoscopy. Operative endoscopic manipulation did not adversely influence pregnancy outcome.
Clomiphene citrate (CC) has known antifecundity effects in animal models. To help define the site of action of this effect, we studied the direct effect of CC on endometrial receptivity by transferring embryos to hormonally prepared prepubertal mice. Prepubertal mice were begun on one of four blinded hormonal preparations consisting of two consecutive 3-day periods of daily injections: oil vehicle, oil-progesterone (P), estradiol (E2)-P, or CC-P. Blastocysts, which had not been exposed to CC, were then surgically transferred to these prepubertal recipients. Fourteen days after embryo transfer, implantations and term pregnancies were counted at necropsy. In this model, CC demonstrated no estrogen agonist effect, and had a significant adverse effect on endometrial receptivity. CC appeared to lower fecundity by a direct endometrial effect.
In Chlamydomonas reinhardtii, mutations on an unusual linkage group, the uni linkage group (ULG), affect structure and function of basal bodies. The ULG shows Mendelian segregation, but its genetic map is circular. Molecular cloning of fragments of the ULG was accomplished by taking advantage of restriction fragment length polymorphisms generated by crosses to Chlamydomonas smithii. These clones were used as probes to determine the size and form of the ULG chromosome; it is a 6-9 megabase linear molecule. Use of the probes for in situ DNA hybridization in cells localized the ULG chromosome to basal bodies.