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Biomedical subjects

M Taylor

Publications and source records attributed to M Taylor.

At least 577 records · Page 32Linked to original sources
PubMed1982

Prevention of water and heat losses from the exposed intestine.

Intestinal exposure results in increased evaporative water and heat losses. The losses are inversely proportional to ambient relative humidity. The purposes of this study were to quantitate water and heat losses from the exposed intestine and to test the plastic bag as a device to reduce these losses. Seventeen piglets were studied. Over a 2 hr period, evaporated losses were considerable--water 96 ml/m2 and heat 56 cal/m2. Prior to placing the intestine in a plastic nonpermeable bag, the exposed intestine lost 54.8 g/m2/hr at an ambient relative humidity of 41.3%. When the intestine was placed in a plastic bag, the relative humidity within the bag rose rapidly to 92.3% and evaporative water and heat losses fell to 0. It was concluded that placing the intestine in a plastic bag allowed the water vapor that escaped from the bowel surface to accumulate about the intestine, raising the relative humidity close to 100% and thereby markedly reducing further evaporation and water and heat losses.

Animals↗
PubMed1982

Neural correlates of optokinetic nystagmus in the mesencephalon of Rana pipiens: a functional analysis.

The effects of lesions of the anuran mesencephalic retinal terminal fields on horizontal optokinetic nystagmus (OKN) were examined. Lesion sites which produced effects upon OKN responses were as follows: BOR, nBOR, peri-nBOR, the large-celled pretectal nucleus, and the dorsal tegmental gray and deep tectal layers. Transection of BOR generally resulted in an increase in saccadic frequently at the lower stimulus velocities. Lesions of nBOR produced a decrease in the frequency of both head and eye saccades in the middle to high range of stimulus velocities. The only lesions which totally abolished horizontal OKN were those located medical to nBOR, in the peri-nBOR region. Lesions of the large-celled pretectal nucleus and dorsal tegmental gray substantially reduced both head and eye saccades at all stimulus velocities. Small lesions in the deep tectal layers also depressed OKN frequency. These studies indicate that horizontal OKN may be mediated by a number of structures within the anuran mesencephalon.

Animals↗
PubMed1982

Rehabilitation management of muscular dystrophy and related disorders: I. The role of exercise.

When evaluating the effect of a modality such as exercise, maturation in children, the rate of progression of the disease, and the degree of weakness should be considered. The two major factors critical in producing overwork weakness are the degree of weakness at the time the exercise program is started and the intensity of the exercise training program. Exercise therapy is apparently not harmful and may be beneficial in patients with motor unit diseases if it is started early in the course of the diseases when muscle fiber degeneration is minimal, and is carried out at submaximal levels.

Animals↗
PubMed1981

Effect of early return to work after elective repair of inguinal hernia: Clinical and financial consequences at one year and three years.

Since January, 1976, male patients undergoing elective unilateral inguinal herniorrhaphy have been included in a trial to see whether early return to normal activity is associated with an increased recurrence rate and to investigate economic consequences. By June, 1981, 500 patients had been reviewed at one year. 2 patients had defaulted. The first 200 patients had been examined at one year and three years. Recurrence was assessed independently, and recurrences were found of which the patient was unaware. The acceptable definition of recurrence was need for reoperation or a truss. The overall recurrence rate at one year was 3.9%. At three years no further recurrences were detected in the first 200 patients. There was no difference in the recurrence rate for those in the "early" group with 8 recurrences in a total of 246 patients and 10 recurrences in 245 patients in the control group. the median inactivity period in the "early" group was 48 days, compared with 65 days in the control. This differences of 17 days is significant (p=0.001). The self-employed "early" group returned to work in a median of 31 days. One-third of workers were losing a median of pounds 31 per week (range pounds 3- pounds 200). Patients can return to normal activity sooner after inguinal herniorrhaphy than has been advised without increasing the recurrence rate at one year and three years and with considerable monetary benefit to one-third of workers.

Clinical Trials as Topic↗
PubMed1981

Activation of progesterone receptor by ATP.

Progesterone-receptor complex from freshly prepared hen oviduct cytosol acquired the ability to bind to isolated nuclei, DNA-cellulose and ATP-Sepharose when incubated with 5-10 mM ATP at 4 degrees C. The extent of this ATP-dependent activation was higher when compared with heat-activation achieved by warming the progesterone-receptor complex at 23 degrees C. The transformation of progesterone-receptor complex which occurred in a time-dependent manner was only partially dependent on hormone presence. The ATP effect was selective in causing this transformation whereas ADP, AMP and cAMP failed to show any such effect. The non-hydrolyzable analogs of ATP, adenosine 5'-[alpha, beta-methylene]triphosphate and adenosine 5-[beta, gamma-imido]triphosphate were also found to be ineffective. Presence of 10 mM sodium molybdate blocked both the ATP and the heat-activation of progesterone-receptor complex. Mn2+ and Mg2+ had no detectable effect on the receptor activation but the presence of Ca2+ increased the extent of ATP-activation slightly. EDTA presence (greater than 5 mM) decreased the extent of receptor activation by about 40% and was, therefore, not included in the buffers used for activation studies. Divalent cations were also ineffective when tested in the presence of 1-5 mM EDTA. The steroid-binding properties of progesterone-receptor complex remained intact under the above conditions when analyzed for steroid-binding specificity and Scatchard analysis. However, the ATP-activated progesterone-receptor complex lost the ability to aggregate when tested on low-salt sucrose gradients. ATP was equally effective in activating the rat-uterine-estradiol-receptor complex at 4 degrees C and influenced the transformation of 4-S receptor form into a 5-S form when analyzed on sucrose gradients containing 0.3 M KCl. The presence of ATP also increased the rate of activation of progesterone-receptor complex at 23 degrees C. These findings suggest a role for ATP in receptor function and offer a convenient method of studying the process of receptor activation at low temperature and mild assay conditions.

Adenosine Triphosphate↗
PubMed1981

The composition of intracellular granules from the metal-accumulating cells of the common garden snail (Helix aspersa).

Certain cells in the hepatopancreas of the common garden snail (Helix aspersa) contain intracellular granules that are sites of metal-ion accumulation. These granules have been extracted and investigated by u.v. and i.r. spectroscopy, atomic-absorption spectroscopy, X-ray microanalysis, thermogravimetric analysis, enzymic assay and microanalysis. The deposits contain about 18% (w/w) water, 5% (w/w) organic matter and 76% (w/w) inorganic material of which the main components are Ca2+, Mg2+ and P2O7(4)-. The possible origin of these granules is discussed, as is their role in detoxifying heavy-metal ions.

Animals↗
PubMed1981

Organ culture passage enhances the oncogenicity of carcinogen-induced hyperplastic mammary nodules.

The purpose of this study was to determine whether culturing hyperplastic mammary nodules in hormone-free medium would enhance their oncogenicity following subsequent transplantation into mammary fat pads. The underlying hypothesis is that the proliferation of transformed cells within the nodules is inhibited by hormone-dependent normal cells also present in the nodules. Accordingly, both primary hyperplastic nodules and tissues from a hyperplastic outgrowth of a primary nodule were maintained as organ cultures for varying periods in hormone-free Medium 199. The results show that whereas noncultured nodules developed mammary tumors at an incidence of only 15%, those passaged in organ culture gave rise to mammary tumors at an incidence of 40 to 43%. This threefold enhancement in the oncogenicity of mammary nodules is interpreted to be due, at least in part, to a reduction in the normal mammary cell content of nodules. Consistent with this interpretation is the observation that cultured nodules gave rise to mammary outgrowths that were predominantly hyperplastic, whereas noncultured nodules generated outgrowths with varying proportions of hyperplastic and normal ductal mammary tissue.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1981

Transepidermal water loss in the infant surgical patient.

Evaporative water loss from skin of the newborn surgical patient is a critical factor in overall water balance and an important source of heat loss. We studied 15 infant surgical patients under the following clinical conditions: (1) exposed babies; (2) infants covered by cloth drapes and lying on a cloth blanket; (3) infants covered by a plastic drape and lying on a cloth blanket; (4) babies lying on a plastic sheet and covered by a plastic sheet; and (5) infants placed in a plastic bag. This study demonstrated that evaporative water loss of the infant surgical patient can be significantly reduced by placing impermeable plastic sheets over and under the baby. This allowed water vapor to accumulate about the baby, increasing the relative humidity and reducing the evaporative water loss. An even further reduction in transepithelial water loss was accomplished by utilizing a plastic bag.

Body Temperature Regulation↗
PubMed1981

Heat exchange in the nose.

Studies of the effects of nasal respiration on the lower respiratory tract, and on metabolic processes generally, have largely been confined to those occurring during inspiration. Expiration through the nose has equally profound effects and has been studied in detail in some animals. Under certain circumstances both heat and water loss from the body can be altered by changes in the nasal mucosa. These changes appear to be under the control of the autonomic nervous system and are influenced by the need to balance heat loss with heat production. The clinical and ecogeographical significance of these findings are discussed.

Animals↗
PubMed1981

Effects of dopamine, ethanol, and mannitol on cardiopulmonary function in patients with adult respiratory distress syndrome.

Dopamine, ethanol, and mannitol were investigated to determine if they could increase pulmonary blood flow and oxygen delivery without significantly increasing intrapulmonary shunt. These drugs were studied in adult patients with respiratory distress following trauma, operation, or sepsis. Intravascular pressure, cardiac output, oxygen consumption and delivery, and limb blood flow and peripheral oxygen delivery were measured in all patients. Hypotensive patients received dopamine in incremental doses of 2 mu g/kg/min until either mean arterial pressure increased 15 mm Hg or heart rate increased by more than 15 beats/min. Ethanol was given as 10% ethanol in 5% dextrose at 2 ml/kg/hr. Mannitol was given as 25 gm of a 25% solution in a single bolus followed by infusion of 8 to 25 gm of 20% solution (mean 10 +/- 2 gm) as a continuous intravenous drip over 1 hour. No drug produced a significant change in intrapulmonary shunt. Ethanol produced significant (p less than 0.05) increases in cardiac index, heart rate, oxygen consumption, and oxygen delivery. Dopamine significantly decreased pulmonary vascular resistance while increasing systemic blood pressure. Visceral blood flow apparently increased while the peripheral vascular response to ischemia remained intact. Mannitol increased oxygen delivery and consumption in both the total body and limb. Thus in patients with adult respiratory distress syndrome (ARDS), increases in pulmonary blood flow can be achieved with several distinct pharmacologic agents without significant increases in intrapulmonary shunt. These increases in flow are generally accompanied by increases in oxygen delivery without increased pulmonary vascular resistance.

Adolescent↗
PubMed1980

Light-dark adaptation of bacteriorhodopsin in triton-treated purple membrane.

Solubilization of purple membrane with Triton X-100 yields Triton micelles containing bacteriorhodopsin monomers. The absorption maximum of dark-adapted solubilized bacteriorhodopsin is blue-shifted to 549 nm. Light adaption increases the absorbance by 4% and shifts the absorption maximum to 553 nm, i.e., the extent of light adaptation is considerably less than in intact purple membrane. Extraction of dark-adapted bacteriorhodopsin in Triton yields a 13-cis- to all-trans-retinal ratio of 58 : 42 which changes after light adaptation to 38 : 62. It has been shown by Sperling et al. (Sperling, W., Carl, P., Rafferty, Ch.N. and Dencher, N.A. (1977) Biophys. Struct. Mech. 3, 79-94) that light adaptation in intact purple membrane occurs through a branching of the 13-cis photoreaction cycle, so that part of the pigment during each cycle crosses over into the all-trans photoreaction cycle. We explain the decreased extent of light adaptation in solubilized bacteriorhodopsin by assuming a significant back reaction from the all-trans to the 13-cis cycle. This assumption predicts a wavelength dependence of the extent of light adaptation, which is born out by experiment.

Bacteriorhodopsins↗