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Biomedical subjects

G H Smith

Publications and source records attributed to G H Smith.

At least 109 records · Page 6Linked to original sources
PubMed1985

Flecainide: a new class Ic antidysrhythmic.

Flecainide acetate is a new orally active antidysrhythmic agent classified in the Ic category. Flecainide is effective in suppressing 88 to 100 percent of abnormal cardiac rhythms in the form of complex ventricular dysrhythmias, including couplets, ventricular tachycardia, reentrant junctional tachycardia, and Wolff-Parkinson-White syndrome. Flecainide appears to have a greater effect on conduction than on repolarization and only minimal effects on hemodynamic parameters. Flecainide is rapidly and completely absorbed after oral administration and has a 13-hour elimination half-life, allowing for twice-daily dosing regimens. Flecainide is generally well tolerated, with dizziness, blurred vision, nausea, and headache the most common side effects. Flecainide has been shown to be superior to quinidine and disopyramide in suppressing ventricular ectopic activity and may be considered a first-line oral agent for this indication. It is believe that flecainide has enough therapeutic advantages to be added to drug formularies.

Action Potentials↗
PubMed1985

Survey of consumer users of a statewide drug information service.

A survey of consumers who had used a state-supported drug information center (DIC) was conducted to determine reasons for and frequency of use of the DIC and opinions about the services of the DIC. The Arizona Poison and Drug Information Center (APDIC) mailed questionnaires to 281 lay persons who had requested information about use of prescription or nonprescription drugs. The questionnaires were sent only to callers who responded affirmatively when asked to participate in the survey. Of 154 (54.8%) respondents (83.8% women), 40.9% were using no prescription drugs at the time of the survey and 83.8% purchased fewer than two nonprescription drugs per month. Approximately 44% said they tried to obtain drug information at least once per month. Pharmacists were named as the most frequent source of drug information for nonprescription drugs, but information about prescription drugs was sought more frequently from physicians and reference books. APDIC was mentioned most frequently as a source of information about all drugs (both prescription and nonprescription). Nearly all respondents said the information from APDIC was helpful and the service should be continued. Drug information consumers looked to this DIC to meet a demand not being met by pharmacists or physicians in the community. Consumers viewed the information as valuable and used this service because it was available and accessible.

Adult↗
PubMed1984

Aeromonas hydrophila: an outbreak of hospital infection.

Aeromonas hydrophila is a Gram-negative water-borne organism widely distributed in the environment. This organism is a recognized cause of diarrhoea and an opportunist pathogen in immunosuppressed patients. An outbreak of hospital-acquired infection which included three cases of pneumonia is reported. The organism was isolated from 19 patients.

Aeromonas↗
PubMed1984

Multiple indicators of stress in an 'active' job--cardiothoracic surgery.

Eight members of a cardiac surgery team were monitored for a variety of stress indicators. These included self-reports of felt stress, observations of behavior related to ECG activity, and measurements of urinary cortisol and 3-methoxy-4-hydroxy-mandelic acid (VMA). Observations were made on 12 separate days spread over a 3-month period. Results indicate moderate to low levels of perceived stress with high levels of satisfaction and high levels of support. ECG data showed wide individual variation; heart rates even during operations were not excessively high (mean, 100 beats per minute). VMA levels were within the normal range. Cortisol levels were above the normal range on 72% of measurements and mean levels were positively related to length of experience. Days when self-perceived stress was reported were associated with higher levels of cortisol but not of VMA. The study failed to support predictions about responses to "active" jobs derived from Karasek's job-strain model.

Cardiac Surgical Procedures↗
PubMed1984

Increased concentration of an indigenous proviral mouse mammary tumor virus long terminal repeat-containing transcript is associated with neoplastic transformation of mammary epithelium in C3H/Sm mice.

Increased amounts of mouse mammary tumor virus (MMTV) proviral transcripts were found in RNA dot blots from MMTV-negative, C3H/Sm mouse mammary tumors which arose spontaneously or were induced by hormonal or chemical carcinogens or both. Other dot blots probed with a long terminal repeat (LTR) probe showed that LTR (MMTV)-containing transcripts were disproportionately represented in these tumor RNAs. Different segments of the MMTV genome were used in sequential hybridizations to Northern blots to determine relative sequence content and size of MMTV transcripts in transformed mammary tissues, as compared with those in lactating mammary glands. Increased amounts of 4.4-kilobase env and 8.1-kilobase genomic MMTV transcripts were detected with an env probe in many of the tumor RNAs examined. Hybridization of the same Northern blots containing tumor RNAs with an LTR probe revealed a 2.2-kilobase transcript which was prominent in RNAs from chemically-induced, hormonally-induced, and spontaneous mammary tumors relative to those from lactating mammary glands. The LTR-containing transcript did not possess significant homology to either env or gag-pol probes. This distinctive, transformation-enhanced, 2.2-kilobase transcript may contain mouse cellular sequences in addition to LTR sequences or it may represent the message for a nonstructural viral protein encoded within the LTR open reading frame of one or more of the four C3H/Sm MMTV proviral genes.

Animals↗
PubMed1984

Expression of pregnancy-specific genes in preneoplastic mouse mammary tissues from virgin mice.

Experimentally induced breast cancer is often preceded by the appearance of preneoplastic lesions which possess the attributes of hyperplastic normal tissue. These lesions can be isolated and carried as stably transplantable outgrowth lines which continue to morphologically resemble differentiating mammary tissue (Medina, D. Methods Cancer Res., 7: 3-53, 1973). We established seven serially transplantable hyperplastic alveolar nodule (HAN) outgrowth lines from virgin mouse mammary tissues following induction by mouse mammary tumor virus, dimethylbenz(alpha)-anthracene, and/or pituitary isografts. The expression of mammary differentiation-specific casein genes was measured in these hyperplastic outgrowths by immunocytochemistry, specific radioimmune precipitation, and blot hybridization of total RNA. All seven HAN outgrowth lines were immunologically positive for casein both in situ and upon explant culture. Unlike explants from normal virgin mouse mammary gland, exposure to insulin, hydrocortisone, and prolactin induced an increase in casein synthesis in HAN explant cultures which was independent of DNA synthesis. [35S]Methionine-labeled polypeptides synthesized in explant cultures of HAN outgrowths freshly isolated from virgin hosts were analyzed by radioimmune precipitation and gel electrophoresis. This analysis demonstrated that all major species of casein, alpha (Mr 46,000), beta (Mr 27,000), and gamma (Mr 25,000), were constitutively (i.e., in the absence of lactogenic stimuli) expressed in these preneoplastic alveolar mammary outgrowths. In support of this observation, RNA homologous to beta- and alpha-casein cDNA probes was often detectable in total RNA preparations from freshly isolated fragments of HAN outgrowths. A second mammary differentiation specific gene product, alpha-lactalbumin, was also detected in HAN outgrowths both in situ and following explant culture. Enzymatically active alpha-lactalbumin was present in extracts of freshly isolated HAN outgrowth tissues and was detectable in these same tissues by immunoperoxidase. In general, alpha-lactalbumin synthesis was increased during explant culture in the presence of lactogenic hormones; however, in contrast to casein synthesis, insulin-hydrocortisone-prolactin-induced increase in alpha-lactalbumin production in vitro was occasionally dependent upon DNA synthesis as it is in explants from normal virgin mouse mammary tissue.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1983

Surgical experience in the management of spontaneous pneumothorax, 1972-82.

In the past 11 years 233 patients have undergone 241 parietal pleurectomies for either recurrence of their spontaneous pneumothorax or failure to respond adequately to management by tube drainage. Major complications occurred in 3.7% of cases, with transaxillary apical pleurectomy engendering significantly fewer complications than full pleurectomy through a posterolateral thoracotomy. The significantly larger number of minor complications, however, in patients undergoing full pleurectomy was largely due to the larger number of patients with chronic obstructive lung disease in this group. On the basis of our experience we advocate the use of transaxillary apical pleurectomy for the younger age group with recurrent pneumothoraces and a full pleurectomy in the older age group, who frequently present because of failure to respond satisfactorily to tube drainage during their initial pneumothorax and often have lung disease secondary to chronic obstructive lung disease which is not confined to the apex of the upper lobe.

Adolescent↗
PubMed1982

Mouse mammary tumor virus proviral sequences congenital to C3H/Sm mice are differentially hypomethylated in chemically induced, virus-induced, and spontaneous mammary tumors.

C3H/Sm mice have lost the exogenous milk-borne mouse mammary tumor virus (MMTV) characteristic of the C3H strain and have a very low (1.5%) incidence of spontaneous mammary tumors, yet they are highly susceptible to mammary carcinogenesis by either chemical carcinogens or infection with the milk-borne virus. We have analyzed the MMTV proviral DNA content of normal tissues and of spontaneous, virus-induced, and chemically induced mammary tumors by restriction endonuclease digestion and Southern blot analysis. Although the results clearly showed additional MMTV sequences in the virus-induced tumor which are not present in normal liver DNA, none of the spontaneous or chemically induced tumors could be shown to contain either newly acquired exogenous or amplified endogenous MMTV sequences. Interestingly, mammary tumors arising in C3H/Sm mice treated simultaneously with infectious MMTV (C3H) and dimethylbenz[a]anthracene (DMBA) possessed new exogenous MMTV DNA even though no quantitative change in tumor production was observed when these mice were compared with C3H/Sm mice treated with DMBA alone (Smith et al., Int. J. Cancer 26:373-379, 1980). Our data indicate that the endogenous MMTV proviral units are extensively methylated in normal tissues, such as livers and normal nonlactating mammary glands. In the absence of MMTV (C3H), we found that in the rare, spontaneously occurring C3H/Sm mammary tumors, certain endogenous MMTV sequences were specifically hypomethylated. Hypomethylation of endogenous MMTV sequences was also noted in the chemically induced mammary tumors, even though radioimmune competition assays for MMTV gp52 and p28 are negative (Smith et al., Int. J. Cancer 27:81-86, 1981). Our results support the conclusion that amplification of endogenous MMTV sequences is not intrinsic to C3H/Sm mouse mammary tumors arising spontaneously or after induction by chemicals. On the other hand, integration of exogenous MMTV DNA into the genome was a constant feature of mammary tumors developing in MMTV (C3H)-infected C3H/Sm mice, even when DMBA was used as the carcinogen. Hypomethylation of some endogenous MMTV sequences is characteristic of C3H/Sm mammary tumors, whether spontaneous or induced by chemicals, which suggests that these sequences are located in actively transcribing regions of the tumor cell genome.

5-Methylcytosine↗
PubMed1982

Coronary artery surgery using inverted internal mammary artery.

A 56-year-old man requiring multiple coronary artery bypass grafts but without enough suitable vein was operated upon using the retrograde flow of the right internal mammary artery to supply to posterior descending coronary artery. Relief of angina and non-ischaemic areas on the scan with thallium-201 supports our intention to use this method when other techniques are not possible.

Angina Pectoris↗
PubMed1982

Serum quinidine determination: comparison of mass-spectrometric and extraction-fluorescence methods.

A comparison of two analytical methods of quinidine plasma determination--the modified extraction fluorometric method and the mass spectrometric method--was made. Plasma supplies collected at steady state from normal human volunteers participating in a bioavailability study were analyzed, using both methods. A total of 359 samples were analyzed. Comparison of both sets of values, by linear regression, yielded an r2 value of 0.84. The results of this comparison were consistent with the results reported by others, confirming that the commonly used extraction fluorometric method of quinidine determination is sufficiently accurate for monitoring quinidine plasma concentrations in the patient care setting, as well as for bioavailability comparisons between products.

Humans↗