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Biomedical subjects

R F Smith

Publications and source records attributed to R F Smith.

At least 181 records · Page 10Linked to original sources
PubMed1979

Mediation of footshock sensitivity by serotonergic projection to hippocampus.

The present experiments assessed the effects of changes in serotonergic function on footshock sensitivity, as determined by a quantified version of the flinch-jump assessment method. In Experiment 1, depletion of telencephalic serotonin by PCPA injection, medial forebrain bundle lesion, or septal lesion, produced increases in reactivity which were correlated with reductions in telencephalic serotonin levels. In all cases, this increased sensitivity was reversed by injections of d, 1-5-hydroxytryptophan (5-HTP) which restored telencephalic serotonin levels to normal. This effect of 5-HTP had not previously been demonstrated in septal lesioned animals, and overall levels of reactivity of septal animals to other stimuli were also reduced by 5-HTP. Experiment 2 tested the effects of hippocampal lesion on the 5-HTP effect in animals when serotonin depletion produced by either PCPA or septal lesion. Hippocampal lesion, while not increasing footshock sensitivity further, significantly attenuated the effectiveness of 5-HTP in restoring sensitivity to normal. The results suggest that hippocampus may be an important site of action of serotonin in modulating reactivity to footshock, and that failure of raphe lesions to increase reactivity may be due to failure to adequately deplete hippocampal serotonin.

5-Hydroxytryptophan↗
PubMed1979

Factors affecting isolation and identification of Haemophilus vaginalis (Corynebacterium vaginale).

The rate of isolation of organisms resembling Haemophilus vaginalis (Corynebacterium vaginale) from vaginal specimens was not significantly affected by anaerobic versus carbon dioxide incubation atmospheres or whether specimens were inoculated on isolation media immediately after collection or after a delay of 6 h. Forty-one clinically isolated strains were provisionally divided into 30 H. vaginalis strains and 11 H. vaginalis-like (HVL) strains based on morphological and growth characteristics. The H. vaginalis strains were less reactive in API-20A identification test strips, (Analytab Products, Inc.) using Lombard-Dowell broth, than in a modified basal medium that contained proteose peptone no. 3 (Difco). The numbers and kinds of substrates fermented by 30 clinical and 2 reference strains of H. vaginalis varied among conventional, API, Minitek (Baltimore Biological Laboratory), and rapid buffered substrate fermentation systems. A greater number and variety of carbohydrates were fermented by the 11 HVL strains more consistently in all four test systems. Analysis of volatile and nonvolatile fermentation end products by gas-liquid chromatography did not reveal significant differences between the H. vaginalis and HVL strains. However, the latter group grew in peptone-yeast extract-glucose broth, whereas the H. vaginalis strains did not grow without the addition of starch to peptone-yeast extract-glucose. All of the reference and clinical strains were similar in their susceptibilities to a variety of antimicrobial compounds except sulfonamides, which inhibited the HVL strains and bifidobacteria but not the H. vaginalis strains. Sulfonamide susceptibility or resistance corresponded in part to the H. vaginalis and HVL-bifidobacteria strain reactions on selected conventional fermentation substrates. Susceptibility or resistance to sulfonamides and metronidazole in conjunction with fermentation tests is described to aid in the separation of H. vaginalis from other possibly unrecognized biotypes of H. vaginalis or other vaginal bacteria that presumptively resemble the organism. A human blood medium known as V agar was also of considerable value in distinguishing H. vaginalis from HVL strains, because only the H. vaginalis strains produced diffuse beta-hemolysis on V agar.

Bacteriological Techniques↗
PubMed1978

Scopolamine does not affect footshock sensitivity in the rat.

To test the generality of the finding of Feigley, et al. [8] that scopolamine increases sensitivity/reactivity to footshock, rats were tested under either scopolamine or saline conditions for sensitivity to footshock in an automated version of the flinch-jump paradigm. There was no significant trend toward increased sensitivity following scopolamine injection at any of the response magnitudes assessed. Since the previous study included an operant response in the measure of sensitivity, it was suggested that apparent effects of scopolamine on reactivity to footshock are dependent on the inclusion of an operant response in the measure of reactivity, and are not due to changes in sensory thresholds.

Animals↗
PubMed1978

Spinal cord damage in surgery of the abdominal aorta.

The incidence, etiology, and clinical manifestations of spinal cord damage after abdominal aortic operations and abdominal aortography are defined on grounds of the authors' experience and of a survey of the pertinent literature. In the authors' experience the incidence of cord damage was 0.25% (three of 3,164) after abdominal aortic operations and 0.01% (two of 17,494) after abdominal aortography. As regards postoperative cord complications in the authors' series, they occurred only in cases of aneurysm, were 10 times more common in ruptured than in unruptured aneurysms, and the neurological loss usually was complete flaccid paraplegia (five of eight or 62%) with high mortality (three of eight or 38%), and rare partial (two of eight or 25%) or complete (one of eight or 13%) recovery. Recovery was more likely the lesser than neurological loss. The cause of postoperative spinal cord damage was ischemia resulting from the interruption of a critical radicular artery at the lower thoracic or high lumbar vertebral levels in the presence of anomalously located greater radicular or infrarenal radicular arteries. High aortic clamping and hypotension increased the probability of this occurrence, which essentially was unpredictable and, therefore, unavoidable. In postartographic cases the cord damage is more variable in its extent, and its cause is a chemical insult brought about by flooding the anterior spinal artery with contrast medium to which the patient probably is hypersensitive. In both groups treatment of the established clinical picture (paraplegia) is confined to support and rehabilitation.

Aged↗
PubMed1978

Aneurysms of the renal artery: problems of prognosis and surgical management.

The clinical course of 29 patients bearing 36 renal artery aneurysms was reviewed. The majority of the lesions (30 of 36 or 83%) were detected incidentally in the course of angiographic examination, mostly in the study of peripheral atherosclerotic arterial disease. Twenty-five lesions 2.0 cm or less in diameter, treated conservatively and observed during a period of time of from 1 to 17 years, remained clinically silent. In 10 patients (with 11 lesions) surgical treatment was employed. For eight patients the surgical treatment consisted of reconstructive excision and repair, with excellent results in all cases but one for a period of observation of from 1 to 17 years. In one patient aneurysmal dilatation of a vein bypass graft resulted in nephrectomy 2 years following operation. In the remaining two patients nephrectomy was required. Unless hypertension or pregnancy complicates the clinical picture, renal arterial aneurysms 1.5 cm or less in diameter can be observed safely by periodic angiography. Surgical repair of an aneurysm is recommended regardless of size if pregnancy cannot be avoided and hypertension is uncontrolled, and in aneurysms 1.5 cm or less in diameter which show an increase in size. A number of reconstructive vascular procedures have proved successful. Ex vivo repair may be an organ-saving technical aid.

Adult↗
PubMed1977

Translumbar aortography: a study of its safety and usefulness.

We reviewed that clinical courses of 14,550 patients in whom translumbar aortography was performed. The principal aim of the survey was to determine the incidence of major and fatal complications attributable to this diagnostic study, as an index of its safety. We found that in this group, seven major (0.05%) and two fatal (0.014%) complications occurred. The corresponding incidences for transfemoral catheter aortography reported in the literature were found to be 1.34% and 0.06%, respectively. Translumbar aortography, when performed under the proper indications and appropriate conditions, has a degree of safety equal to or greater than that of transfemoral catheter aortography, and its diagnostic reliability within its technical scope is high.

Aortic Aneurysm↗
PubMed1977

Comparisons between direct microscopic and cultural methods for recognition of Corynebacterium vaginale in women with vaginitis.

The frequency with which clue cells could be detected in Gram-stained vaginal smears and/or cervical Papanicolaou (Pap) smears was compared with the frequency of Corynebacterium vaginale (Haemophilus vaginalis) isolation in a group of 236 female patients, of whom 221 had vaginitis. Vaginal clue cells were found most often in women from whom C. vaginale was isolated (P = 0.00006) whereas, conversely, clue cells in cervical Pap smears were reported more frequently in women with negative cultures for this organism (P = 0.006). C. vaginale isolations were made more frequently from women with both vaginal and cervical clue cells reported (P = 0.000088). However, the combined false positive-false negative vaginal clue cell rate in the patients studied was 36.5%. Neither the detection of vaginal clue cells nor the isolation of C. vaginale was significantly affected by whether or not patients had trichomoniasis (P = 0.25). Trichomonas vaginalis detection in cervical Pap smears and vaginal isolation were related (P = 0.00005), whereas the same relationship was not significant for fungi (P = greater than 0.05).

Cytodiagnosis↗
PubMed1977

Tellurite reduction test to aid in the recognition of Corynebacterium vaginale.

Corynebacterium vaginale (Haemophilus vaginalis) does not reduce potassium tellurite. When a 1% aqueous solution of tellurite is added to starch agar plates previously inoculated with vaginal discharge material, other starch-fermenting and most non-starch-fermenting bacteria rapidly reduce tellurite to produce black or gray colonies. This test is a useful adjunct to methods for rapid presumptive identification of C. vaginale. C. vaginale is more susceptible to tellurite inhibition than a variety of other gram-positive bacteria.

Bacteriological Techniques↗
PubMed1977

Gram stain evaluation of the quality of sputum specimens for mycobacterial culture.

A group of 34 mycobacteria, consisting of 25 Mycobacterium tuberculosis and nine strains of three other species, was isolated from 400 expectorated sputum specimens submitted on 148 patients from county-wide sources. Eight strains (24% of the total) were isolated from specimens evaluated by Gram stain to be oropharyngeal fluids. The remaining 26 strains were isolated from ungradable specimens and those primarily of lower respiratory origin. It was concluded that the random examination of sputum by Gram stain to determine the specimen's quality for mycobacterial isolation is not necessary.

Humans↗
PubMed1977

Suppression of ventricular ectopic depolarizations by tocainide.

In a previous clinical study we demonstrated that tocainide is effective in the suppression of ventricular ectopic depolarizations (VEDs) after single oral doses. This information provided the basis for evaluating this drug's antiarrhythmic efficacy after multiple dose administration according to a loading-maintenance regimen. Twelve patients with stable VEDs were given loading doses of tocainide (400-600 mg) with maintenance doses every 12 hours. Every 48 hours the dose was increased until either arrhythmia suppression to less than 25% of VED frequency during placebo administration or side effects occurred. Computer analysis of 12-hr telemetric ECGs taken 24-36 hr after each dosage increment documented effective suppression (76-95%) in 8 of 12 patients. Those subjects demonstrating suppression were randomly assigned to a cross-over study of placebo or active drug at the dosage found effective in the dose-ranging phase. Dosages for the cross-over stage ranged from 400 to 1100 mg every 12 hours. Comparison of the two five-day periods documented suppression in these patients (mean +/- SE = 83.3 +/- 4%). No serious side effects or undue drug accumulation occurred during the study. The data indicate that tocainide can effectively suppress VEDs for 8-12 hours in many patients and that continuous suppression could be possible on an 8-12 hr dosage regimen.

Anti-Arrhythmia Agents↗
PubMed1977

Facial plexiform neurofibroma.

Facial plexiform neurofibroma is a relatively rare manifestation of Von Recklinghausen's neurofibromatosis. Two patients with extensive facial tumor involvement are presented, each having undergone wide local resection after multiple previous local excisions had failed to control the tumor and its locally deforming and destructive effects. A discussion of the problem, its etiology, pathogenesis, natural history, prognosis and suggested treatment is presented.

Adolescent↗
PubMed1977

Behavioral and neurochemical effects of prenatal halothane.

Permanent neurobehavioral toxicological effects have been theorized to occur at the lowest doses of a toxic agent if exposure occurs during early development compared to exposure during adulthood. Data are reviewed showing the exposure to 10 ppm of halothane from conception to day 60 of life post-partum led to adult rats (>/= 135 days of age) which were hyperalgesic to electric footshock and which committed 30% more errors learning a light-dark discrimination to escape footshock, or learning the shortest path to a food reward in a maze. Exposure only during adulthood to 10 ppm of halothane (from day 60 of life onwards) had no effects. To determine prenatal periods sensitive to halothane, rats were exposed to 12,500 ppm of halothane (with 35% oxygen) on day 3, 10, or 17 of gestation. As adults (>/= 75 days of age) day 3- and day 10-exposed rats, but not day 17-exposed rats, were hyperalgesic and committed 40% more errors in learning a visual discrimination to escape footshock. Food and water consumption, body weight, and running wheel activity were unaffected. Finally, adult rats exposed to 10, 50, or 100 ppm of halothane from conception to day 28 postpartum had 15% less 5-hydroxyindoleacetic acid in brain, but normal 5-hydroxytryptophan, noradrenalin, and dopamine. The possibility is discussed that the hyperalgesia noted above results from a permanently reduced turnover of brain serotonin produced by halothane present in brain at days 10-15 of gestation.

Abnormalities, Drug-Induced↗
PubMed1977

Cytologic diagnosis of adenoviral epidemic keratoconjunctivitis by direct immunofluorescence.

A direct immunofluorescence technique for the diagnosis of acute adenoviral keratoconjunctivitis and pharyngoconjunctivitis was found to be a reliable, sensitive, and specific technique for the detection of soluble adenoviral antigens in epithelial cells on conjunctival scrapings of patients with epidemic keratoconjunctivitis. Of 25 patients with clinical findings consistent with epidemic keratoconjunctivitis or pharyngoconjunctival fever, all had positive diagnostic scrapings by direct immunofluorescence.

Adenoviridae Infections↗
PubMed1976

Congenital arteriovenous anomalies of the limbs.

Observations in 33 patients with congenital arteriovenous fistulas described ten years ago have been extended with the addition of 49 other cases; the clinical, pathologic, and roentgenographic characteristics of these lesions in the entire group of 82 patients have been summarized. The findings in the entire group over the additional observation period have confirmed the conclusions previously reached, namely, that (1) these clinically extremely varied lesions have a unitary (developmental) cause; (2) for rational management, angiographic investigation is indispensable to establish their extent and complexity; (3) with few exceptions, their radical cure by surgical means is impossible; and (4) the large majority of patients do well on a carefully supervised conservative regimen, with surgical intervention reserved for individually defined instances.

Angiography↗