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Biomedical subjects

W R Wilson

Publications and source records attributed to W R Wilson.

At least 325 records · Page 18Linked to original sources
PubMed1977

Tetracyclines, chloramphenicol, erythromycin, and clindamycin.

Tetracyclines are active in vitro against most urinary tract pathogens, Chlamydia, Mycoplasma pneumoniae, Brucella, rickettsiae, and Nocardia. Chloramphenicol is used primarily for anaerobic infections, Haemophilus influenzae meningitis, and infections due to Salmonella typhi. Erythromycin is active in vitro against M. pneumoniae, Streptococcus pneumoniae, and group A beta-hemolytic streptococci. Erythromycin may be used as prophylactic therapy for subacute bacterial endocarditis and for recurrence of acute rheumatic fever in patients who are allergic to penicillin. Clindamycin should be used only for the treatment of anaerobic infections. Tetracycline may cause gastrointestinal upset; phototoxic dermatitis; hepatitis, especially in pregnant females; discoloration of teeth and bone dysplasia in the human fetus and children; and suprainfections, especially oral and anogenital candidiasis. Tetracycline should be used with caution in patients with renal insufficiency. The most important toxic effect of chloramphenicol is bone marrow suppression, which is dose related and idiosyncratic. The incidence of undesirable side effects associated with the use of erythromycin is low. Gastrointestinal irritation is the most common; cholestatic hepatitis may occur with erythromycin estolate. Pseudomembranous colitis is the most important toxic effect associated with clindamycin.

Anaerobiosis↗
PubMed1976

Studies on the nature of a prostaglandin receptor in canine and rabbit vascular smooth muscle.

The contractile response of rabbit renal arteries and canine tibial arteries to prostaglandins A2, B2, F2alpha, E1, E2, D2, and B1 was associated with a reduction in total sulfhydryl group content of smooth muscle. The total sulfhydryl content of rabbit renal and canine tibial arteries and was not affected by norepinephrine or potassium chloride. Reduction of disulfide groups with dithiothreitol (DTT) selectively inhibited contractile responses to angiotensin and prostaglandins; 5,5'-Dithiobisnitrobenzoic acid (DTNB), a sulfhydryl group-oxidizing agent, reversed the inhibitory effect of DTT on the contractile responses to prostaglandins. Alkylation of free sulfhydryl groups with ethacrynic acid did not affect the contractile response of isolated canine tibial or rabbit renal arteries to any agonist studied. Ethacrynic acid added to muscle strips exposed to DTT resulted in alkylation of sulfhydryl groups produced by reduction of disulfide bonds and irreversibly prevented DTNB-induced reversal of DTT inhibition of contractile responses to prostaglandins. However, addition of ethacrynic acid to muscle strips contracted by prostaglandins did not inhibit subsequent responses to these acidic lipids. These findings support the hypothesis that contractile responses of rabbit renal and canine tibial arteries to prostaglandins are dependent on interactions between prostaglandins and disulfide groups located in or on the vascular smooth muscle cell, and the concept that membrane disulfide groups may be integral components of vascular smooth muscle receptors for prostaglandins.

Angiotensin II↗
PubMed1976

Idiopathic late-onset immunoglobulin deficiency with functional T-cell deficiency.

The common features in our two patients were late onset of infections that are known to complicate both T-cell and B-cell deficiencies, decreased numbers of circulating B-cells with low serum immunoglobulin levels, and normal numbers of circulating T-cells, which were, however, defective in the response to delayed hypersensitivity skin test antigens and to mitogens in vitro. The composite of clinical and immunologic aberrations is consistent with the presence of an immune deficiency involving the B-cell system quantitatively and the T-cell system qualitatively.

Adolescent↗
PubMed1976

Leukocyte chemotaxis in diabetic patients and their nondiabetic first-degree relatives.

Leukocyte chemotaxis wasmeasured in 108 subjects: 20 normal controls, 36 insulin-taking diabetics (15 being index patients), and 52 nondiabetic first-degree relatives of index patients. The relatives had a mean chemotactic index (CI) significantly lower than that of the controls (individually, 25 per cent had CIs lower than the lowest of the controls); and the diabetics had a mean CI significantly lower than that of the relatives. The impairment of leukocyte chemotaxis measured in the first-degree relatives of diabetic index patients does not appear to be associated with an increased susceptibility to infection and suggests that the impaired leukotaxis is due to an inherent defect--perhaps genetic--in leukocyte function.

Adolescent↗
PubMed1976

Incidence of bacteremia in adults without infection.

To determine the incidence of bacteremia in healthy adults, blood cultures were obtained from 240 patients who had no demonstrable foci of infection. Five patients (2.1%) had positive blood cultures. Staphylococcus epidermidis was isolated from four patients and Alcaligenes faecalis from one. In each of these patients, the organism isolated probably represented contamination rather than bacteremia.

Adult↗
PubMed1975

Accuracy of the Bing and Rinne tuning fork tests.

Fifty children seen in an ENT clinic received the Bing and Rinne tuning fork tests, otoscopic examination, and puretone audiometry to determine the accuracy of the tuning fork tests in predicting otoscopic abnormality or conductive hearing loss. Neither tuning fork test showed high accuracy. The Bing test overidentified by yielding negative results (conductive loss) for many ears with normal hearing or sensorineural loss. It correctly identified conductive loss or otoscopic abnormality only slightly better than chance57% to 66% of the time. The Rinne test identified with high accuracy those ears with a 40 dB or greater air-bone gap. For air-bone gaps of 10-35 dB, only 27% of the ears gave negative results, meaning correct identification. However, when a negative Rinne occurred, the result was in error only 2% of the time.

Adolescent↗
PubMed1975

Affiliation and social discrimination produced by brief exposure in day-old domestic chicks.

Discrimination between individual strangers and companions was examined in day-old domestic chicks. In one experiment, pecking rates at companions and strangers were observed in pairwise bouts after 16 hr of cohabitation. The discriminability of strangers and companions was varied by means of pre-hatch colouring. Reliable discriminations between individual strangers and companions emerged as early as the first minute of the encounter. Discriminative cues provided by artificial colouring were found not to be necessary in establishing social discrimination. In a second experiment, undyed chicks were housed in pairs for 1, 4 or 16 hr. Half of the pairs lived in cages that separated companions by a wire screen, and half were housed in undivided cages. Observations of pecking in four-way bouts confirmed previous findings and demonstrated that the opportunity to peck during exposure may be a necessary condition in producing social discrimination. Antecedent conditions that lead to the development of affiliative bonds simultaneously appear to establish social discrimination.

Animals↗
PubMed1975

The influence of pre-information on the rating of articulation.

This study evaluated whether pre-information influenced experienced and inexperienced speech clinicians' ratings of a child's articulation. All clinicans received the same written pre-information report, except that for one half of both groups the report ended with the statement that the child's articulation problem was mild-to-moderate and for the other half that is was moderate-to-severe. Each clinician completed a standard articulation inventory based on a video-tape presentation and then rated the child's articulation on a nine-point scale. Results on the rating scale were in the direction of the pre-information rating for each group, with the experienced groups' differences being statistically significant. Results on the inventory demonstrated the following : the expected shift for one experienced group, an unexplained very poor scoring of articulation errors by the other experienced group, and no significant difference between the inexperienced clinician groups. We conclude that on the more subjective task---the rating of an articulation problem--an examiner bias effect was noted, with the strongest effect being shown by the experienced clinicians. On the more specific tasks--articulation inventory--the results were equivocal.

Attitude↗
PubMed1975

Alteration of warfarin kinetics in man associated with exposure to an operating-room environment.

The plasma half-life of warfarin (mean +/- SE) in five normal, nonmedicated control subjects given a single 40 mg/m2 oral dose of warfarin was 38.8 +/- 4.1 hours. It was essentially the same (37.7 +/- 2.6 hours) in these subjects when determined again four months later. The effect of the single dose of warfarin on prothrombin complex activity (prothrombin response) was determined by calculating the area under the curve obtained by plotting prothrombin time (seconds) versus time after the warfarin dose (hours). The prothrombin response in control subjects was 1670 +/- 64 sec-hr initially and essentially the same at the end of the four-month interval (1730 +/- 96 sec-hr). Plasma warfarin half-life and prothrombin response in seven anesthesiology residents were 32.1 +/- 3.6 hours and 1337 +/- 78 sec-hr at the start of their training period, i.e., before working in the operating room. Four months later, their plasma warfarin half-lives were significantly prolonged (49.3 +/- 4.8 hours) and the prothrombin responses were significantly greater (1552 +/- 22 sec-hr) compared with their initial values. The alteration of warfarin kinetics appeared to be due mainly to inhibition of warfarin metabolism, presumably related to the repeated exposure of these subjects to an operating room environment.

Administration, Oral↗
PubMed1975

Regulation of blood flow in Paget's disease of bone.

Previous studies have demonstrated an increase in blood flow to extremities involved by Paget's disease of bone. It has been assumed that the increase in blood flow is through bone, but warmth of skin overlying Pagetic bone suggests that cutaneous blood flow might be increased. In three patients with Paget's disease involving one extremity, we compared blood flow in "Pagetic" extremities with flow in the contralateral normal extremities. Resting blood flow (measured with water plethysmographs) was 14.2plus or minus2.9 (meanplus or minusSE) ml/min times 100 ml extremity in the Pagetic limbs. The contribution of cutaneous flow to the increase in extremity blood flow was evaluated with epinephrine iontophoresis, which suppresses flow to skin but not to underlying tissue. Epinephrine iontophoresis of the Pagetic extremities decreased blood flow from 14.2plus or minus2.9 to 3.6plus or minus1.5 ml/min. Local heating (which increases cutaneous flow only) failed to increase blood flow in the Pagetic extremities as much as it did in the normal extremities. This suggests that cutaneous vessels in the Pagetic extremities were already dilated. During heating, blood flow in the normal extremities was similar to resting flow in the Pagetic extremities; this indicates that increases in cutaneous flow could account for most of the increase in total blood flow in the Pagetic extremities. Adrenergic control of blood flow to the Pagetic extremities was compared with that of the normal extremities. Vasoconstrictor responses to reflex stimuli in the Pagetic extremities were reduced; when vasoconstriction occurred it was gradual and sustained after termination of the stimuli, which suggests an exaggerated humoral response but reduced neural response to the stimuli. Intravenous epinephrine produced vasoconstriction in the Pagetic extremities and vasodilatation in the normal extremities. In summary, responses to epinephrine iontophoresis and heating suggest that the increase in blood flow in Pagetic extremities is primarily the result of cutaneous vasodilatation.

Blood Vessels↗
PubMed1975

Selective beta-1 receptor blockade with oral practolol in man. A dose-related phenomenon.

The purpose of this study was to test the hypothesis that oral administration of a low dose of practolol in man produces selective beta-1 receptor blockade, whereas oral administration of a high dose blocks both beta-1 and beta-2 receptors. Normal men were studied 2-4 h after a single oral dose of practolol (1.5 or 12 mg/kg) and after placebo. Effects on beta-1 receptors were studied by measuring heart rate responses to exercise. Effects on beta-2 receptors were tested by measuring forearm vascular responses to brachial arterial infusions of isoproterenol. Neither dose of practolol altered base-line heart rate, forearm vascular resistance, and arterial pressure, Both low and high doses significantly attenuated heart rate responses to exercise. Forearm vasodilator responses to isoproterenol were attenuated by the high dose, but not the low dose, of practolol. Serum concentrations of practolol 2 h after administration of the drug and at the time of the studies of forearm vascular responses averaged 0.5+/-0.1 (SE) and 5.9+/-1.0 mug/ml for low and high doses of practolol, respectively. The results indicate that the phenomenon of selective beta-1 receptor blockade in man is related to the dose and serum concentration of practolol selectively block beta-1 receptors; a high dose and serum concentrations block both beta-1 and beta-2 receptors.

Administration, Oral↗
PubMed1975

Enhancement of neural and thermal vasoconstriction by prostaglandin B1.

The vascular effects of prostaglandin B1 (PGB1) were studied during constant-flow perfusion of the canine hindpaw. The effects of PGB1 (50-200 ng/kg/min ia) on systemic and hindpaw perfusion pressures and on responses to local cooling (4 degrees C for 90 sec) and local heating (45 degrees C for 60 sec) were measured in 15 dogs. PGB1 (50-100 ng/kg/min) decreased perfusion pressure without any significant effect on systemic arterial pressure. Higher concentrations of PGB1 (200 ng/kg/min) elevated perfusion pressure to control values. The pressor responses to local cooling were increased from 11 to 32 mmHg while the dilator responses to local heating and nitroglycerin were reduced during infusions of PGB1. PGB1 also enhanced the pressor responses to norepinephrine or tyramine. These findings support the conclusions that (1) low concentrations of prostaglandin B1 enhance neurotransmitter release with minimal effects on vascular smooth muscle cells and (2) these effects are not secondary to increased perfusion pressures or vascular wall stresses since infusions of PGB1 resulted in vasodilation.

Animals↗
PubMed1975

Prosthetic valve endocarditis.

From January 1963 until January 1974, 45 patients had prosthetic valve endocarditis. Symptoms of prosthetic valve endocarditis developed within 2 months after operation (early onset) in 16 patients (36%) and more than 2 months after operation (late onset) in 29 patients (64%). Overall mortality among the 45 patients was 56% (88% among those with early onset and 40% among those with late onset). Medical therapy alone was curative in 60% of the surviving patients. Combined medical and surgical therapy was curative in 40% of the survivors. The most frequent isolates in the early-onset group were Staphylococcus aureus (44%) and Gram-negative bacilli (38%); associated mortality was 86% and 83%, respectively. The most frequent isolates in the late-onset group were viridans streptococci (41%) and Gram-negative bacilli (31%); the mortality was 25% and 22% respectively. Suggestions are offered for operative antimicrobial prophylaxis and for medical and surgical treatment of prosthetic valve endocarditis. Prompt surgical replacement of an infected prosthesis is necessary when medical therapy fails.

Bacteria↗
PubMed1975

Interaction of prostaglandin A2 and prostaglandin B2 on vascular smooth muscle tone, vascular reactivity and electrolyte transport.

The effects of prostaglandin A2 (PGA2) and prostaglandin B2 (PGB2) on vascular smooth muscle tone, electrolyte movements and responses to vasoactive stimuli were evaluated with superfused canine tibial arteries. PGA2 and PGB2 constricted superfused tibial arteries. PGB2 was 10.7 (8.3-14.1) times more potent as a constrictor than PGA2. PGA2 and PGB2-induced vasoconstriction was associated with a decrease in 22Na efflux and a tendency toward an increase in cellular sodium (expressed as micromoles per gram of wet weight). These prostaglandins also decreased the total potassium content of tibial arteries. 45Ca exchange was enhanced by PGA2 and PGB2. The time course of PG-induced increases in 45Ca efflux was similar to the temporal increase in force produced by PGA2 and PGB2. The duration of the contractile response to barium chloride was greatly prolonged during superfusion with both PGA2 and PGB2. These effects were probably not mediated by PG-induced alterations in the resting membrane potential of tibial arteries since presumed depolarization by both high potassium and zero-potassium physiologic saline solutions did not mimic the effects of these prostaglandins on vascular smooth muscle tone or responses to barium chloride. These data suggest that PGA2 and PGB2 may increase tone of vascular smooth muscle by inhibition of those processes involved in sequestration of calcium ion, i.e., the relaxation process, rather than acting on the contractile process.

Animals↗
PubMed1975

Anaerobic bacteremia.

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Gram-Negative Anaerobic Bacteria↗