Megaloblastic pancytopenia in a patient receiving concurrent methotrexate and trimethoprim-sulfamethoxazole treatment.
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Abscess↗
Biomedical subjects
M Davis
Publications and source records attributed to M Davis.
Influence of progesterone on guinea pig gallbladder motility in vitro.
Experiments were designed to examine the in vitro effect of progesterone (1.6 X 10(-5) M; 8 X 10(-5) M) on the tone and contractility of guinea pig gallbladder smooth muscle. Muscle strips from animals of both sexes were stimulated with acetylcholine, cholecystokinin-octapeptide, histamine, and potassium prior to and 15 min after exposure to progesterone. The results were as follows: progesterone at all doses studied completely abolished spontaneous phasic contractions; progesterone produced a concentration-dependent decrease in resting tension; the hormone significantly decreased the maximal contractile response to each of the agonists but had no effect on either the ED50 of the acetylcholine and cholecystokinin dose-response curves; and estrogen priming is not necessary to demonstrate an inhibitory effect of progesterone. The data suggest that progesterone can directly affect the force-generating capacity of gallbladder smooth muscle both at rest and in response to stimulation. However, because of the relatively high concentration of hormone used, the physiological significance of the data must remain speculative.
Acetylcholine↗
Xanthogranulomatous abscess of a mullerian duct remnant. A rare lesion of the rectum and anus.
A rare example of xanthogranulomatous inflammatory mass and abscess of a Mullerian duct remnant involving the anorectal area is reported. A barium enema showed a bilobed precoccygeal mass of moderate size involving the posterior aspect of the distal rectum. Computed tomography (CT) showed two nonfatty, round masses, one of which contained a small central cystic area. The other mass had a homogeneous appearance and was believed to be in the wall of the rectum. The pathologic specimen showed organizing abscesses and a chronic xanthogranulomatous inflammation in tissue compatible with urogenital tissue, presumably a Mullerian duct remnant. This is the first documented report of anorectal xanthogranulomatous abscess in a Mullerian duct remnant with radiologic findings and histopathologic correlation. Though rare, this lesion should be considered in the differential diagnosis of extrinsic and intramural rectal masses seen on barium enema and CT examinations.
Abscess↗
Newborns' discrimination of chromatic from achromatic stimuli.
Two experiments assessed newborns' ability to discriminate chromatic from achromatic stimuli. In Experiment 1, newborns differentiated gray from green, from yellow, and from red: For each of these hues they preferred chromatic-and-gray checkerboards over gray squares matched in mean luminance, even though the luminance of the gray checks was varied systematically over a wide range so as to minimize nonchromatic cues. However, newborns showed no evidence of differentiating gray from blue: At some luminances they showed no preference for a blue-and-gray checkerboard over a gray square. In Experiment 2, newborns differentiated red from gray but appeared not to differentiate blue from gray: Following habituation to a series of gray squares of varying luminance, they looked longer at a red square than at a gray square of novel luminance but showed no such pattern of recovery to a blue square. The results imply that newborns have some, albeit limited, ability to discriminate chromatic from achromatic stimuli and hence, that they are at least dichromats.
Adult↗
The design and calibration of a startle measurement system.
The present study sought to determine appropriate instrumentation for amplification and calibration of cages used to measure the acoustic startle response in rats. Fourier analysis indicated that the characteristic frequency of the rat startle response is about 5-15 Hz. This value was consistent in cages differing widely in resonant frequency, among several different transducers and across a range of large and small startle responses. Given this characteristic frequency range of startle, it is suggested that amplifiers fitted with band pass filters centered at about 10 Hz should be ideal for measuring startle while simultaneously excluding non-startle activity. A device is described which vibrates startle cages at 10 Hz, since this seems most appropriate for calibrating the sensitivity of a startle system. Data are presented showing that this type of calibrator is more valid than an impact-type calibrator.
Animals↗
Fear conditioning, pre-pulse inhibition and drug modulation of a short latency startle response measured electromyographically from neck muscles in the rat.
The present study evaluated if startle measured electromyographically in the neck muscles (having a 5 msec latency) would exhibit behavioral and pharmacological plasticity known to alter startle measured in a stabilimeter device. A total of 15 rats were implanted with bilateral EMG electrodes in the dorsal neck muscles and subsequently exposed to a variety of manipulations known to affect the whole-body startle response. The peak-to-peak EMG response that occurred within 10 msec of startle stimulus onset displayed pre-pulse inhibition, enhancement by prior fear conditioning, inhibition by clonidine, and enhancement by strychnine. The data are discussed in terms of modulation of neural transmission along a primary startle-mediating pathway.
Animals↗
A new prognostic index in surgery and parenteral feeding: the ratio of triiodothyronine to reverse triiodothyronine in serum (T3/rT3 ratio).
Serum concentrations of albumin, triiodothyronine (T3), and reverse triiodothyronine (rT3) were measured in 46 patients on the first day after routine gastrointestinal surgery, and the molar ratio T3/rT3 was calculated. The median value of this ratio, but not of albumin, was significantly lower in 11 who subsequently suffered major septic complications than in the remainder. Measurement of the ratio correctly predicted the outcome of 80% of individuals. The T3/rT3 ratio, midarm muscle circumference (MAMC), triceps skin fold (TSF) and serum concentrations of albumin and transferrin were measured in 23 patients at referral for parenteral feeding. Median values of T3/rT3 ratio, MAMC and transferrin, but not of the other parameters, were significantly lower in nine who died than in survivors. Measurements of the ratio, MAMC and transferrin correctly predicted the outcome of 87%, 78% and 74% of individuals, respectively.
Journal Article↗
Adverse reactions to the intravesical administration of doxorubicin hydrochloride: report of 6 cases.
We report 6 cases of adverse systemic reactions to the intravesical instillation of doxorubicin hydrochloride for the treatment of recurrent superficial transitional cell carcinoma of the bladder. Although local reactions to this drug are common they rarely are life-threatening. Significant systemic toxicity has not been reported.
Aged↗
Traumatic rectal hematoma following anal rape.
We describe the case of a 28-year-old male prisoner with a traumatic rectal hematoma caused by anal rape. Barium enema showed a large rectal mass confirmed to be a hematoma by proctoscopic examination. Surgery was performed due to a falling hemoglobin level, and an 800-mL hematoma was evacuated. The patient became febrile following surgery, and computed tomography revealed a pelvic mass consistent with recurrent hematoma or abscess. Repeat surgery showed recurrent hematoma. The patient recovered uneventfully.
Adult↗
Lesions of the amygdala, but not of the cerebellum or red nucleus, block conditioned fear as measured with the potentiated startle paradigm.
Rats were given 10 light-shock pairings on 2 successive days. At 24-48 hr following training, groups of rats received bilateral transection of the cerebellar peduncles, bilateral lesions of the red nucleus (which receives most of the cerebellar efferents), or bilateral lesions of the central nucleus of the amygdala. Control rats were sham operated. At 3-4 days after surgery, the rats were tested for potentiated startle (increased acoustic startle in the presence of the light previously paired with shock). Potentiated startle was blocked by lesions of the central nucleus of the amygdala. Transection of the cerebellar peduncles or lesions of the red nucleus did not block potentiated startle. A second experiment in which a visual prepulse test was used indicated that the blockade of potentiated startle observed in the animals with amygdala lesions could not be attributed to optic tract damage. A third experiment demonstrated that the absence of potentiation in the animals with amygdala lesions was not simply due to a lowered startle level ceiling, because these animals could show increased startle with increased stimulus intensity and with administration of strychnine, a drug that increases startle. Taken together, the results are consistent with the hypothesis that the amygdala is involved in fear conditioning, because potentiated startle is a measure of conditioned fear.
Amygdala↗
Habituation, prepulse inhibition, fear conditioning, and drug modulation of the acoustically elicited pinna reflex in rats.
A reliable component of the acoustic startle response in animals is a flexion of the ears, the pinna reflex. One goal of the present investigation was to develop a preparation and apparatus suitable for analyzing the pinna reflex in the awake rat. A second goal was to examine the pinna reflex under behavioral and pharmacological conditions known to affect other response systems, such as whole-body startle, and determine whether the pinna response is a valid model for analyzing behavioral plasticity. The amplitude of the pinna reflex in spinally transected rats was directly related to stimulus intensity and exhibited short-term habituation, prepulse inhibition, and enhancement by prior fear conditioning. Also, pinna response amplitude increased following systemic administration of strychnine and was decreased following clonidine. It is concluded that this preparation and response system are valid for studying various forms of behavioral modification. Implications of these findings are discussed in terms of the potential utility of this response system in investigating the cellular correlates of behavioral plasticity in mammals.
Adaptation, Psychological↗
Pharmacological and anatomical analysis of fear conditioning using the fear-potentiated startle paradigm.
Pharmacological and anatomical analysis of fear conditioning using the fear-potentiated startle paradigm are reviewed. This test measures conditioned fear by an increase in the amplitude of a simple reflex (the acoustic startle reflex) in the presence of a cue previously paired with a shock. This paradigm offers a number of advantages as an alternative to most animal tests of fear or anxiety because it involves no operant and is reflected by an enhancement rather than a suppression of ongoing behavior. Fear-potentiated startle is selectively decreased by drugs such as diazepam, morphine, and buspirone that reduce fear or anxiety clinically. Electrical stimulation techniques suggest that a visual conditioned stimulus ultimately alters acoustic startle at a specific point along the acoustic startle pathway. Relevant visual structures implicated in potentiated startle include the lateral geniculate nucleus, visual cortex, and deep and intermediate layers of the superior colliculus. The central nucleus of the amygdala and the caudal branch of the ventral amygdalofugal pathway projecting to or through the substantia nigra are also necessary for potentiated startle to occur. Electrical stimulation of the central nucleus of the amygdala markedly increases acoustic startle. By combining these behavioral, anatomical, physiological, and pharmacological approaches, it should soon be possible to determine each neural pathway that is required for a stimulus signaling fear to alter startle behavior. Once the exact structures are delineated, it should be possible to determine the neurotransmitters that are released during a state of fear and how this chemical information is relayed along these pathways so as to affect behavior.
Animals↗
Protective agents for acetaminophen overdose.
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Acetaminophen↗
Purification of rat angiotensinogen.
A method of purifying rat angiotensinogen in three chromatography steps with a yield 3-4 times better than previous methods is described. Using chromatofocusing media for two steps and DEAE-affigel blue for the third step it was possible to separate angiotensinogen into three major peaks with pI of 5.25 (peak B), 4.80 (peak C) and 4.50 (peak D). Peaks B and C were completely purified with recoveries of 12% and 17% and specific activities of 21.8 and 20.0 micrograms AI/mg protein respectively. Analytical SDS-PAGE showed a 53,000 dalton band in both peaks with additional 51,000 and 57,000 dalton bands in peak C.
Angiotensinogen↗
Radiographic and endoscopic findings in human whipworm infection (Trichuris trichiura)
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Barium Sulfate↗
Ethanol metabolism in the generation of new antigenic determinants on liver cells.
Antibodies directed against ethanol altered liver cell components have been detected in the serum of nearly 50% of patients with alcoholic liver disease although the pathogenetic mechanisms are unclear. The importance of ethanol metabolism in the generation of new antigenic determinants on liver cells was investigated by in vivo inhibition of alcohol or acetaldehyde dehydrogenase and an induced cytotoxicity assay. There was a significant reduction in cytotoxicity to hepatocytes isolated from rabbits treated with ethanol 1 g/kg when the metabolism of ethanol to acetaldehyde by alcohol dehydrogenase was inhibited. In contrast when the oxidation of acetaldehyde was inhibited by disulfiram cytotoxicity was significantly enhanced. These results show that ethanol metabolism is integral to the expression of the ethanol related determinant and suggest that an impaired ability to metabolism acetaldehyde could lead to the development of immunological reactions to alcohol altered liver membrane antigens.
Alcohol Oxidoreductases↗
The use of different lipids to express serum tocopherol: lipid ratios for the measurement of vitamin E status.
Plasma tocopherol was measured in 85 alcoholic patients and 40 control subjects from a local factory. Cholesterol, triglycerides and phospholipids were measured individually and summed to give an estimate of total serum lipids. Plasma tocopherol concentrations of the alcoholics were significantly lower than those of the controls and showed wide variation from marked deficiency to the upper limit of the normal range. Using regression analysis, 1.11 mumol tocopherol/mmol total lipids were calculated as the threshold of deficiency equivalent to 0.8 mg tocopherol/g total lipid established by Horwitt et al. The sensitivity and specificity of other tocopherol:lipid ratios for identifying vitamin E deficiency was compared with the tocopherol:total lipid ratio. Thresholds of deficiency for the different tocopherol:lipid ratios were calculated. The tocopherol:cholesterol+triglyceride ratio was found to be almost as powerful in identifying vitamin E deficiency as the tocopherol:total lipid ratio (sensitivity 95%, specificity 99%). Of the tocopherol:individual lipid ratios, the tocopherol:cholesterol ratio gave the best results (sensitivity 86%, specificity 94%).
Alcoholism↗
Etiology of developmental disabilities in Soweto, South Africa.
A retrospective review was undertaken of the records of 725 children who attended the neurodevelopmental clinic at the Baragwanath Hospital in Soweto, South Africa. Most children presented at an early age (less than 2-6 years). The etiological factors were prenatal, 4 per cent; perinatal, 41 per cent; postnatal, 21 per cent. Seventy-one per cent of the perinatal factors were a result of birth related problems in full-term infants; only 22 per cent of this group were represented by premature and low birthweight infants, contrasting sharply with data from industrialized centers. Almost a third of the postnatal causes were a result of acute intracranial infections. Another 13 per cent were a result of the metabolic consequences of acute gastroenteritis. Thus a high proportion of problems were preventable through provision of adequate nutrition, mass immunization campaigns, and adequate primary health care services including antenatal and obstetric management.
Child↗