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Biomedical subjects

M Lee

Publications and source records attributed to M Lee.

At least 1,009 records · Page 56Linked to original sources

A case report of benign recurrent intrahepatic cholestasis.

A case of benign recurrent intrahepatic cholestasis was reported. A man had first experienced jaundice at the age of twenty-five, and suffered three subsequent attacks over the next five years. These attacks were characterized by prodromal severe pruritus. During the icteric phase, serum levels of total bile acids increased, most being conjugates of primary bile acids. Electron microscopy revealed that the bile canaliculi were filled with an increased volume of granular substances. Some bile canaliculi fused together resulting in the formation of abnormally elongated channels which abutted on the Disse space. These observations suggest bile regurgitation through the channel of altered canaliculi. In convalescence, these bile canaliculi disappeared. Every attack was followed by complete recovery of liver structure and function.

Adult↗

Effect of fentanyl and naloxone on the P300 auditory potential.

The effect of fentanyl (opioid agonist) and naloxone (morphine antagonist) on the amplitude, area and latency of the P300 auditory potential was studied in patients undergoing minor surgical procedures. Fentanyl (5.0 micrograms/kg), naloxone (3.0 micrograms/kg) and isotonic saline (for control) were injected intravenously through a catheter just before surgery, and following a single-blind procedure and three different pharmacological paradigms with three consecutive conditions each: (1) initial baseline (C), saline (S) and late baseline (C'); (2) C, fentanyl (F) and C'; (3) C, naloxone (N) and C'. Fentanyl significantly reduced the amplitude and area with no changes in the latency of small (S) and large (L) P300 potentials. Concomitantly, fentanyl increased the number of omitted counts of the target tones of the "odd ball" P300 test and the spatial threshold of the two point discrimination test in patients with small and large P300 potentials. Naloxone significantly increased the amplitude and area and decreased the latency of the small P300 potential and decreased the amplitude and area with no changes in latency of the large P300 potentials. Concomitantly, naloxone decreased the number of omitted counts of the patients with small but not large P300 potentials and decreased the spatial threshold in patients with both small and large P300 potentials. Neither fentanyl nor naloxone produced systematic changes in the evaluation of pain and hearing of patients with small and large P300 potentials. Although dramatic changes in pulse, blood pressure, respiration and EEG were found in some cases immediately after the administration of fentanyl and naloxone, these changes were not consistent and were not present at the time other tests were performed.

Adult↗

Morbilliform skin eruption owing to diethylstilbestrol.

We describe an unusual case of morbilliform skin eruption caused by diethylstilbestrol in a patient with stage D prostatic cancer. A widespread erythematous maculopapular rash and urticaria appeared with repeated challenges of diethylstilbestrol and resolved with drug withdrawal. In addition, the literature on various types of dermatitis medicamentosa in male patients with prostatic cancer treated with diethylstilbestrol is reviewed.

Aged↗

Methanogenesis in a Thermophilic (58 degrees C) Anaerobic Digestor: Methanothrix sp. as an Important Aceticlastic Methanogen.

Aceticlastic methanogens and other microbial groups were enumerated in a 58 degrees C laboratory-scale (3 liter) anaerobic digestor which was fed air-classified municipal refuse, a lignocellulosic waste (loading rate = 1.8 to 2.7 g of volatile solids per liter per day; retention time = 10 days). Two weeks after start-up, Methanosarcina sp. was present in high numbers (10 to 10 CFU/ml) and autofluorescent Methanosarcina-like clumps were abundant in sludge examined by using epifluorescence microscopy. After about 4 months of digestor operation, numbers of Methanosarcina sp. dropped 2 to 3 orders of magnitude and large numbers (most probable number = 10 to 10/ml) of a thermophilic aceticlastic methanogen morphologically resembing Methanothrix sp. were found. Methanothrix sp. had apparently displaced Methanosarcina sp. as the dominant aceticlastic methanogen in the digestor. During the period when Methanothrix sp. was apparently dominant, acetate concentrations varied between 0.3 and 1.5 mumol/ml during the daily feeding cycle, and acetate was the precursor of 63 to 66% of the methane produced during peak digestor methanogenesis. The apparent K(m) value obtained for methanogenesis from acetate, 0.3 mumol/ml, indicated that the aceticlastic methanogens were nearly saturated for substrate during most of the digestor cycle. CO(2)-reducing methanogens were capable of methanogenesis at rates more than 12 times greater than those usually found in the digestor. Added propionate (4.5 mumol/ml) was metabolized slowly by the digestor populations and slightly inhibited methanogenesis. Added n-butyrate, isobutyrate, or n-valerate (4.5 mumol/ml each) were broken down within 24 h. Isobutyrate was oxidized to acetate, a novel reaction possibly involving isomerization to n-butyrate. The rapid growth rate and versatile metabolism of Methanosarcina sp. make it a likely organism to be involved in start-up, whereas the low K(m) value of Methanothrix sp. for acetate may cause it to be favored in stable digestors operated with long retention times.

Journal Article↗

Plasma amino acids and glucose levels in the rat fetus and dam after chronic maternal alcohol consumption.

To evaluate the effect of chronic maternal alcohol consumption on plasma amino acid and glucose levels in both the fetus and the mother, female Sprague-Dawley rats were divided into 3 dietary treatment groups. Group 1 (alcohol) was fed ad libitum a stock diet plus 20% alcohol in drinking water for at least 4 weeks before mating and 30% alcohol during gestation. Group 2 was pair-fed the stock diet plus corn starch calorically equivalent to the amount of alcohol consumed by group 1 animals. Group 3 (control) received the stock diet and water ad libitum. On day 21 of gestation the fetuses of alcohol-treated dams weighed significantly less than those of the control and pair-fed groups. Fetal plasma glucose levels were significantly lower in the alcohol group when compared to those of the pair-fed and control groups, while the maternal glucose levels were similar in all three treatment groups. Plasma amino acid concentrations showed no corresponding trends in mother and fetus. Only proline was significantly reduced and alpha-amino-n-butyric acid elevated in the alcohol-treated dams when compared to the pair-fed and control rats. In the fetal plasma, only aspartic acid was significantly lower in the alcohol group when compared to the other two groups. A moderate degree of dehydration occurred in the alcohol-treated dams, but plasma albumin was within normal levels. It is concluded that the marked decrease in the concentration of plasma glucose in alcohol-exposed fetuses may be partially responsible for their retarded growth.

Alcoholism↗

Comparative efficacy of piperacillin versus carbenicillin for complicated urinary tract infections.

In this controlled, randomized clinical trial we compared piperacillin and carbenicillin in the treatment of complicated urinary tract infections. 24 patients received piperacillin 150 mg/kg/day for 7.2 +/- 2.75 days and 17 patients received carbenicillin 200 mg/kg/day for 7.5 +/- 2.90 days. Patients were evaluated for clinical and bacteriologic responses and tolerance to therapy. Although the clinical cure rate significantly favored carbenicillin treatment (p less than 0.01), the sum of the percentages of cases with clinical cure and clinical improvement were similar between groups: 91.6% for piperacillin and 88.2% for carbenicillin. The bacteriologic cure rates for piperacillin and carbenicillin patients (54.1 and 47.0%, respectively) were not significantly different (p greater than 0.05). The low cure rates in our study were probably the result of uncorrected/uncorrectable genitourinary tract abnormalities. Superinfections developed in 12.5 and 17.6% of piperacillin and carbenicillin patients, respectively, and were due to Klebsiella pneumonia, Proteus mirabilis, Citrobacter diversus, and Pseudomonas aeruginosa. Overall, side effects were mild, reversible, and did not require discontinuation of treatment. However, carbenicillin caused elevations in liver enzymes more frequently than piperacillin (p less than 0.05). Based on our data, we recommend reserving piperacillin monotherapy for patients who are poor candidates for aminoglycosides, or are on severe sodium restriction, and have serious complicated urinary tract infections due to susceptible organisms. We do not recommend piperacillin alone for empiric treatment of complicated urinary tract infections.

Bacterial Infections↗

Frequency analysis of the first and second heart sounds of humans.

Each sound signal of the first and the second heart sounds of humans was divided into three equal segments. The frequency spectrum of each segment was analyzed using the fast-Fourier-transform technique. Theory predicts that if the first and second heart sounds are caused principally by the respective vibrations of the atrioventricular and semilunar valves, then the frequency of these sounds should increase with an increase in the pressure difference across these valves. In other words, the frequency of the heart sounds should increase with time, as the pressure difference across these valves increases with time for most of the duration of the sounds. Our frequency analysis, however, showed that there is no systematic relation between the predominant frequency of successive segments of the sound signals. This therefore appears to indicate that it is quite unlikely that the vibrations of the heart valves are the principal contributor to the origin of the first and second heart sounds.

Adult↗

Respiratory rehabilitation in severe restrictive lung disease secondary to tuberculosis.

There is a need for portable and less expensive devices for patients with chronic respiratory insufficiency. The case of a 44-year-old Hispanic woman is illustrative. The patient had severe restrictive lung disease secondary to right phrenic nerve crush/pneumoperitoneum and left pneumonectomy/decortication for bilateral lower lobe tuberculosis. In 1969, 12 years after her last operation, she developed dyspnea, coryza, and somnolence. She was hospitalized with a PaO2 of 30mmHg; PaCO2 of 77mmHg and a pH of 7.28. Pulmonary function tests showed alveolar hypoventilation and her resting ventilation was between 2.26 to 3.74L/min. Her vital capacity was 1130cc (37% of predicted value) and maximum breathing capacity was 36L/min (44% of predicted value). From 1969, she used a poncho (wraparound) ventilator for her long-term respiratory care and modified the poncho suit to meet her personal needs. In 1971, she discovered that a mouth intermittent positive pressure ventilation (MIPPV) method, often used by patients with neuromuscular disorders, was easier to apply. Since then, she has continued to use a Bantam Respirator with MIPPV and a lipguard/mouthpiece during the night, and the respirator with a mouthpiece for a few hours during the days. However, when she has an upper respiratory infection or feels tired, she finds that she needs the greater rest and comfort that the poncho provides. With the assistance of these two respiratory devices, she has been able to complete her education, marry, and lead a fulfilling life in the community. This patient is considered the first person with severe lung pathology to utilize MIPPV for sleep.

Adult↗

Intestinal folate conjugase activity and folate absorption in the ethanol-fed pregnant rat.

The effect of chronic alcohol consumption on intestinal folate conjugase activity and on the absorption of both mono- and polyglutamyl folates was evaluated in pregnant rats. Female rats were given either 20% ethanol in drinking water and rat chow ad libitum (alcohol group) or were fed rat chow and water ad libitum (controls). After four weeks on this regimen all animals were bred and the alcohol group was changed to 30% ethanol in water. Conjugase activity, in vivo folate absorption, and fetal and placental weights were measured on day 20 of gestation. The controls consumed more food than the alcohol group, which was reflected in significantly higher body weights of the control group. Fetal weights of the alcohol group were significantly lower than those of the controls, but litter size and placental weights were not significantly different. No significant differences were found in intestinal conjugase activity between the two groups of animals, but the intestinal absorption of both folate mono- and pentaglutamate were significantly higher in the alcohol than in the control group. The absorption of folate pentaglutamate was higher than that of folate monoglutamate in both groups of animals but the differences were not significant. These findings indicate that ethanol ingestion during pregnancy does not seem to interfere with either folate polyglutamate hydrolysis or folate absorption.

Animals↗

A biophysical, morphological and morphometrical survey of the eye of the small shark (Hemiscyllium plagiosum).

The biophysical and morphological characteristics of the small shark's ( Hemiscyllium plagiosum ) eye were studied. The focal lengths of the lens were found to be very short. A small proportion of cones were present in the retina and this proportion varied with the weights of the sharks. The topographic distribution of cones in different segments of the retina was also presented.

Animals↗

An autoradiographic study of the retinofugal projections in the shark, Hemiscyllium plagiosum.

The retinofugal projections in the shark, Hemiscyllium plagiosum were studied after unilateral eye injection of tritiated proline. The results showed that each eye in this animal projects not only to the contralateral side of the brain but also to several ipsilateral visual centers including the nucleus suprachiasmaticus, ventrolateral nucleus of the optic tract and the optic tectum. These results suggest that some of the visual centers in this animal receive direct retinal inputs from both eyes as is the case in many other animals and most notably in mammals.

Animals↗

Assay of AHF concentrates and standards: failure to eliminate variability with a monographed assay.

Previous calibration studies have shown a high interlaboratory variability in the potency of the proposed Office of Biologics (National Center for Drugs and Biologics, US-FDA) AHF standard relative to the 2nd International Standard for Factor VIII (Factor VIII:C) (WHO 73/552). This led to the formation of an Industry Collaborative Study group whose objective was to reduce the assay variability. The group, in collaboration with the Office of Biologics and the National Institute for Biological Standards and Control (UK), designed a study based on a monographed one-stage assay protocol, which specified all materials, assay methods, equipment, dilution technique, reagents, assay order, and calculation methodology. All participants received common reagents and samples, with the exception of substrate plasma. It was felt that substrate plasma could not be a common reagent in a monographed assay. However, each laboratory prepared substrate plasma according to the protocol. All data were analyzed by an independent statistical staff. Preparations assayed included two 10-donor plasma pools, the 2nd International Standard for Factor VIII (WHO 73/552), the proposed OoB Lot A internal standard, the participants' own house standards, and commercial AHF concentrate material. The results show a statistically insignificant reduction in the interlaboratory variability, but intralaboratory consistency was generally maintained. The study shows that monographing an assay for Factor VIII.

Adolescent↗

Intestinal absorption of amino acid derivatives: structural requirements for membrane hydrolysis.

The intestinal absorption of L-lysine-p-nitroanilide, L-alanine-p-nitroanilide, and glycine-p-nitroanilide was studied in perfused rat intestine in the presence of a variety of potential competitive inhibitors. The results indicate that the hydrolysis site(s) show side-chain specificity, and that inhibitors require a free amino group in the alpha-position and must be in the L-configuration to be effective. Glycyl-L-proline, a peptide transport inhibitor, had no effect on the absorption rate.

Alanine↗