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Biomedical subjects

H Frank

Publications and source records attributed to H Frank.

At least 127 records · Page 7Linked to original sources
PubMed1986

A comparison of responses to albuterol delivered by two aerosol devices.

Nineteen outpatients with stable obstructive pulmonary disease (mean forced expiratory volume in one second [FEV1], 1.00 + 0.10 L) were evaluated for airway response to albuterol (salbutamol) administered by metered-dose inhaler and Bosch ultrasonic nebulizer (BUSN). Albuterol administered by metered-dose inhaler but not by nebulizer caused a significant increase in FEV1 and the mean forced expiratory flow over the middle half of the forced vital capacity (FEF25-75%) (p less than 0.02). Absolute increase from baseline of FEV1 and FEF25-75% was significantly greater for metered-dose inhaler (0.21 +/- 0.05 L; 0.32 +/- 0.13 L/sec) compared to ultrasonic nebulizer (0.07 +/- 0.03 L; 0.03 +/- 0.04 L/sec) (p less than 0.02). In 11 subjects (mean FEV1, 1.08 + 0.14 L), the placebo effect of inhalation of the diluent from the metered-dose inhaler (Freon) and the ultrasonic nebulizer (isotonic saline solution) was determined. Freon produced the mean increase of 1.5 percent, whereas the ultrasonic aerosol of isotonic saline solution resulted in a mean decrease of 8 percent in FEV1. Therefore, the inferior response to albuterol administered by ultrasonic nebulizer was at least in part due to the superimposed broncho-constriction occurring with ultrasonically administered saline solution. The metered-dose inhaler was more effective than the ultrasonic nebulizer for administration of albuterol in stable obstructive pulmonary disease, and the latter device is not recommended. A specific ultrasonic nebulizer should be prescribed only if its superiority to a metered-dose inhaler can be objectively documented.

Aerosols↗
PubMed1985

The solitary pulmonary nodule. Decision analysis.

The management of a patient with a solitary pulmonary nodule is often problematic. Particularly in older patients and those with cardiorespiratory disease, the risks of intervention frequently equal or exceed its potential benefits. In this paper the choice between expectant management, thoracotomy, and transthoracic needle biopsy is examined for the asymptomatic patient with a solitary pulmonary nodule. We have designed and implemented a computer-assisted decision-analytic model of this clinical situation. The model incorporates age, sex, smoking history, and underlying cardiorespiratory status. It considers the probability of having a malignant nodule, the risks of biopsy and surgery, the sensitivity and specificity of biopsy, the resectability rate of malignant nodules, and the morbidity-adjusted life expectancies of patients in 16 outcome categories. Sensitivity analyses were performed and decision thresholds determined to assess the effect of varying the model's data base. These results can be of assistance in choosing therapy for patients with solitary pulmonary nodules and can provide a better understanding of the factors involved in this decision making process.

Aged↗
PubMed1985

Formation and metabolism of nitrosamines in vivo, monitored by 14N-stable isotope labelling.

Microsomal metabolism of N-nitrosodimethylamine entails release of molecular nitrogen; the extent is determined by 15N stable isotope labelling and mass-spectrometric isotope ratio measurements. Exhalation of labelled nitrogen by rats treated with 15N-dimethylamine and nitrite or 15N-nitrite alone indicates that nitrogen may arise from nitrite via two pathways: either directly from nitrosation of primary amines or from secondary and tertiary amines with subsequent enzymic N-demethylation. The overall yield of nitrosamine formation, N-demethylation and nitrogen-release represent about 0.3-6% or the administered dose of dimethylamine (1.1 mmol/kg), depending upon the dose of nitrite (0.55-2.2 mmol/kg). 15N-stable isotope labelling and mass-spectrometric isotope ratio measurements are powerful tools for assessment of endogenous nitrosamine formation from nitrite. One hundred nmol of labelled nitrogen are easily detectable in vivo; with further methodological refinement the limit of detection may be lowered by two orders of magnitude.

Animals↗
PubMed1984

[Bifonazole for the topical treatment of surface mycoses--progress!].

69 patients with superficial mycosis were treated with 1% Bifonazol cream once a day. 48 of them who suffered from tinea pedis interdigitalis received Bifonazol for 3 weeks, the remaining 21 patients who had superficial candidiasis applied it over a period of 4 weeks. The local tolerance of the cream has been very good. Control examinations 3 and 14 days after treatment proved 59 (89%) of all patients to be cured, i.e. 40 of those who had suffered from tinea pedis and 19 of the group with candidiasis.

Administration, Topical↗
PubMed1984

Binding of trichloromethyl radicals to lipids of the hepatic endoplasmic reticulum during tetrachloromethane metabolism.

Metabolism of tetrachloromethane (carbon tetrachloride) by liver microsomal fraction under anaerobic conditions and in vivo leads to covalent binding of trichloromethyl radicals to lipids. The resulting covalently modified lipids contain two different types of fatty acids: a group of monomeric trichloromethyl fatty acid residues, usually with one double bond less than the precursor fatty acids, and a group of fatty acids that are not sufficiently volatile for gas chromatography. The liquid-chromatographic properties of the latter indicate high molecular mass, presumably due to cross-linking. The chemical structures of the monomeric fatty acids were elucidated, and these support the view that the most significant reactive metabolite of tetrachloromethane is the trichloromethyl radical. The isomer patterns of the monomeric trichloromethyl fatty acids in vitro and in vivo are almost identical, which shows that anaerobic incubation of tetrachloromethane with microsomal fraction very well reflects the processes involved in hepatotoxicity of tetrachloromethane in vivo.

Animals↗
PubMed1984

Determination of N-acetyl-L-cysteine in biological fluids.

For determination of a drug in biological fluids, accuracy and sensitivity of detection of the adopted method are decisive parameters, but practical aspects such as time and necessary instrumentation are equally important. In the case of N-acetyl-L-cysteine, sample pretreatment can be kept at a minimum if sufficiently selective modes of derivatization, chromatography and detection are employed. Its concentration in serum is between 1 and 20 mumol/l; for quantitative analysis capillary gas chromatography and mass fragmentographic detection are employed. For urine with its ten-fold higher concentration the preferred method is reversed-phase high-performance liquid chromatography after thiol-selective derivatization.

Acetylcysteine↗
PubMed1984

Carbon tetrachloride metabolism in vivo and exhalation of volatile alkanes: dependence upon oxygen partial pressure.

Metabolism of carbon tetrachloride in rats at atmospheric and reduced oxygen pressure has been determined indirectly by its disappearance from the inhaled air; it is inversely related to oxygen concentration and increases with decreasing partial pressure, as expected for reductive dehalogenation; oxygen partial pressure has been reduced to about a third of normobaric conditions. Concurrently exhalation of ethane and pentane as indication of lipid peroxidation has been monitored, showing a drastic increase when the oxygen partial pressure is reduced in the presence of carbon tetrachloride. Time course and duration of these processes indicate that the total metabolism of carbon tetrachloride is limited by the concomitant destruction of cytochrome P-450; also, oxidative destruction of polyunsaturated fatty acids apparently does not proceed beyond the end of metabolic activation of carbon tetrachloride. The molar ratios of the amount of metabolized carbon tetrachloride to the amounts of exhaled hydrocarbons lead to the same conclusion, namely that "lipid peroxidation" in this case does not proceed as an autocatalytic, self-propagating chain reaction.

Animals↗
PubMed1984

Anaerobic metabolism of carbon tetrachloride and formation of catabolically resistant phospholipids.

Anaerobic incubation of microsomes with 14C-carbon tetrachloride leads to trichloromethyl radicals which, apart from other detrimental reactions, bind covalently to phospholipids. These labelled lipids are extracted, phosphatidylcholine is isolated and incubated with phospholipase A2 from Naja naja snake venom and from porcine pancreas. Half of the covalently modified phosphatidylcholine is resistant toward phospholipase A2. Distribution of such catabolically resistant phospholipids from the endoplasmic reticulum to other cell organelles may play an important role in the pathway leading from the primary lesion to hepatocyte necrosis.

Anaerobiosis↗
PubMed1984

Human teratocarcinomas cultured in vitro produce unique retrovirus-like viruses.

We have previously reported that among a series of human tumours investigated, only human teratocarcinoma cell lines derived from testicular tumours or pulmonary metastases of patients in Germany and the U.S.A. produced retrovirus-like particles spontaneously, albeit in low amounts. In a recent publication electron microscopical data suggested that the human teratocarcinoma-derived ( HTD ) particles were morphologically closely related, but not identical, to the type C retroviruses of animals. In this communication, the explantation of three human teratocarcinoma cell lines is briefly described. Evidence is presented that HTD particles (i) are synthesized only in a fraction of the epithelioid and differentiating cells; (ii) can be induced biochemically in a manner characteristic of retroviruses; (iii) either are not infectious or possess a peculiar host range; (iv) are immunologically unrelated to animal retrovirus strains; (v) possess an endogenous RNA-dependent DNA polymerase activity that can be banded at 1.16 g/ml in linear sucrose gradients. These results may be taken as suggestive evidence that HTD particles represent a novel group of unique retroviruses.

Antigens, Viral↗
PubMed1984

Effect of transcendental meditation on breathing and respiratory control.

We studied the effect of transcendental meditation (TM) on breathing using 16 experienced meditators and 16 control subjects. In controls, there was no significant difference in minute ventilation (VE), respiratory pattern, or hypercapnic response, whether breathing with eyes open-awake (CA), or with eyes closed-relaxing (CR). In meditators, VE decreased significantly during quiet breathing from 14.0 +/- 0.7 1/min with eyes open-awake (MA) to 12.4 +/- 0.6 1/min during meditation (MM) (P less than 0.02). The change in VE during meditation was due to a decrease in tidal volume (VT) resulting from a shortened inspiratory time (TI). Meditation was associated with a decreased response to progressive hypercapnia from 3.7 +/- 0.4 to 2.5 +/- 0.21 X min-1 X Torr-1 during MA and MM trials, respectively (P less than 0.01). During meditation VT was smaller at a given alveolar PCO2 than during MA studies because of a decrease in mean inspiratory flow rate (VT/TI). These observations suggest that an alteration in wakefulness, more subtle than sleep or the unconscious state, can significantly affect the chemical and neural regulation of breathing.

Adult↗
PubMed1984

Combined therapy with ipratropium and theophylline in asthma.

Ipratropium (40 micrograms) and theophylline (oxtriphylline 400 mg) were administered to 24 asthmatics in a randomized double-blind placebo controlled trial. The combination of these agents produced additive bronchodilation for up to two hours, with a 23 percent maximal increase in FEV1. This regimen promises to be safe, effective therapy for patients with asthma.

Adolescent↗
PubMed1983

Amino acid determination by capillary gas chromatography on Chirasil-Val. Enantiomer labelling and nitrogen-selective detection.

Amino acid analysis by enantiomer labelling and capillary gas chromatography on Chirasil-Val is superior to conventional gas chromatography and ion-exchange chromatography with respect to sensitivity, accuracy and speed. Employment of an alkali flame-ionization detector allows the selective detection of amino acids and suppression of background peaks; in addition, the detectability of amino acids is enhanced. Most nitrogen-selective detectors require meticulous adjustment of the operating conditions, but in combination with enantiomer labelling this is less critical. Maximum sensitivity and selectivity of the alkali-bead flame-ionization detector is achieved with a minimal flow of hydrogen. When using it as the carrier gas in capillary gas chromatography, flow control instead of the common pressure regulation is recommended to avoid a continuous fall of the baseline during temperature programming. Accurate flow control is achieved with a micro-aperture. The benefit of nitrogen-selective detection is especially apparent for histidine and arginine.

Amino Acids↗