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Biomedical subjects

V Chen

Publications and source records attributed to V Chen.

At least 127 records · Page 7Linked to original sources
PubMed1982

Dosage effect of streptozotocin on rat tissue enzyme activities and glycogen concentration.

The effect of different dosages of streptozotocin (STZ) on selected rat tissue enzyme activities and glycogen concentration were investigated. The rats were administered STZ intravenously at 60 (STZ-60), 80 (STZ-80), 100 (STZ-100), and 150 (STZ-150) mg/kg body weight. They were used 3 weeks postinjection. Mortality prior to kill occurred only in the STZ-100 and STZ-150 rats. All diabetic rats showed reduced growth rate, hyperglycemia, hypoinsulinemia, and hyperlipemia. Phosphofructokinase (PFK) and succinate dehydrogenase (SDH) activities were significantly reduced in the red gastrocnemius muscle of all diabetic rats, and in the white gastrocnemius and soleus of STZ-100 and STZ-150 groups. PFK activity in the heart remained unaltered, but SDH activity was below normal. Liver SDH activity was not affected by insulin deficiency. Glycogen content was markedly increased in the heart and decreased in the liver of all diabetic rats. Glycogen content in the skeletal muscle was similar to the controls, except for the lower values in the soleus of STZ-100 and STZ-150 rats. When STZ-80 and STZ-150 rats were given insulin therapy, the STZ-80 rats showed a greater response to the treatment. Despite similar levels of plasma immunoreactive insulin among all groups of diabetic rats, the STZ-100 and STZ-150 rats had higher mortality, greater loss in body weight, and alterations in enzyme activities and glycogen content in the tissues studied.

Animals↗
PubMed1979

Goblet cell carcinoid tumor of the appendix. Report of five cases and review of the literature.

Five cases of goblet cell carcinoid tumor of the appendix showed characteristic histologic features that justified classification of these lesions as mucinous variants of carcinoid tumor. The tumor has low-grade malignancy, and metastases are uncommon. Resemblance to mucinous adenocarcinoma of the appendix is striking, and the features that help to differentiate the two lesions are delineated.

Adenocarcinoma, Mucinous↗
PubMed1978

Cellular adaptations of the ventilatory muscles to a chronic increased respiratory load.

It is not known whether cellular adaptations of the ventilatory muscles are induced by increased respiratory loads. A chronic respiratory load was produced in rats by tracheal banding. Five weeks after the imposition of this increased load, biochemical and histochemical analyses were performed on the diaphragm and intercostal muscles. The oxidative capacity, as indicated by succinate dehydrogenase (SDH) activity, increased 38% in the diaphragm. The capacity for beta-oxidation fatty acids, as indicated by 3-hydroxy-acyl-CoA dehydrogenase (HADH) activity, increased 29%. The glycolytic capacity, as indicated by phosphofructokinase (PFK) activity, did not change. Similar enzymatic adaptations were observed in the intercostal muscles. The proportion of slow-twitch muscle fibers, as indicated by the myofibrillar adenosine triphosphatase (ATPase) stain, increased in the diaphragm, but not in the intercostal muscles. Thus, these ventilatory muscles responded with an increase in their oxidative capacity, and the diaphragm reponded with an increase in the proportion of muscle fibers having the myofibriller ATPase staining characteristic of slow-twich fibers. We conclude that cellular adaptations are induced in the ventilatory muscles by chronic increased respiratory loads.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1976

Hepatic infarction. A clinicopathologic study of seven cases.

Five of the seven cases of hepatic infarction that compose this study were encountered in a series of 442 consecutive autopsies, giving an incidence of one in 88 autopsies. The clinical and laboratory features were suggestive of hepatocellular dysfunction, although in only three cases was the diagnosis considered prior to death. Morphologically, in four of the seven patients, the infarcts were regarded as massive or of submassive proportions and were directly responsible for the patients' death. The majority of infarcts were of recent origin, with the estimated ages ranging from 18 to 72 hours. One was of about two weeks' duration and was the only example in this series associated with cirrhosis.

Adult↗
PubMed1975

The neural control of contraction in a fast insect muscle.

The wing muscles used in singing by the katydid, Neoconocephalus robustus, are extraordinarily fast. At 35 degrees C, the animal's thoracic temperature during singing, an isometric twitch lasts only five to eight msec (onset to 50% relaxation) and the fusion frequency of these muscles is greater than 400 Hz. Stimulating the motornerve to a singing muscle initiates a short (2.5 msec at 35 degrees C), sometimes overshooting depolarization of the muscle fibers. Despite their spike-like appearance, the electrical responses are largely synaptic potentials. The muscle membrane appears to be capable of only weak, electrically-excitable, depolarizing electrogenesis. The short synaptic potentials result in part from rapidly-developing delayed rectification, in part from a low resting membrane resistance (Rm = 162 omega cm2) and a concomitantly short membrane time constant (about 1.5 msec).

Animals↗
PubMedDate not supplied

Aspiration biopsy cytology of lymph nodes in malignant lymphoma.

The cytologic findings of needle aspiration biopsy of lymph nodes in malignant lymphoma are presented. In 42 of 49 cases, a correct cytologic diagnosis was rendered. There was one false-positive diagnosis. The diagnostic accuracy of needle aspiration cytology is high. It helps to select patients for further investigation and treatment, thereby avoiding unnecessary surgery in patients who present with lymphadenopathy. The technique is also useful in the staging work-up of patients with lymphoma and the diagnosis of recurrent disease during the follow-up period.

Biopsy, Needle↗
PubMedDate not supplied

[2 cases of tumor-like changes in the talus].

Tumors and tumor-like conditions in the talus are rare.--In our first case operation revealed a benign osteoblastoma, in the second case an solitary bone cyst. Microscopic findings allowed other diagnoses too, but our diagnoses were made on the basis of clinical appearance and X-ray and histological findings. After local resection and insertion of bone chips in the one case and curettage and filling with bone chips in the other, healing was complete.

Adult↗
PubMedDate not supplied

Rifabutin for experimental pneumococcal meningitis.

Rifabutin is a lipophilic antibacterial with high in vitro activity against many pathogens involved in bacterial meningitis including pneumococci. Resistance to beta-lactam antibiotics in pneumococci is not associated with a decreased sensitivity to rifabutin (30 strains from Germany with intermediate penicillin resistance; MIC range of penicillin: 0.125-1 mg/l, MIC of rifabutin: < 0.008-0.015 mg/l). Rifabutin at doses of 0.625, 1.25, 2.5, 5 and 10 mg/kg/h i.v. was investigated in a rabbit model of meningitis using a Streptococcus pneumoniae type 3 (MIC/MBC of rifabutin: 0.015/0.06 mg/l). The bacterial density in CSF at the onset of treatment was 7.3 +/- 0.6 log CFU/ml (mean +/- SD). Rifabutin decreased bacterial CSF titers in a dose-dependent manner [delta log CFU/ml/h (slope of the regression line log CFU/ml vs. time) at a dose of 0.625 mg/kg/h: -0.16 +/- 0.06 (n = 3), at 1.25 mg/kg/h: -0.20 +/- 0.12 (n = 4), at 2.5 mg/kg/h: -0.24 +/- 0.04 (n = 4), at 5 mg/kg/h: -0.31 +/- 0.10 (n = 8), and at 10 mg/kg/h: -0.29 +/- 0.10 (n = 5)]. At high doses rifabutin was as active as ceftriaxone at 10 mg/kg/h (delta log CFU/ml/h: -0.29 +/- 0.10, n = 10). Two and 5 h after initiation of therapy, CSF TNF-alpha activities were lower with rifabutin 5 mg/kg/h than with ceftriaxone (medians 2 vs. 141 U/ml, p = 0.005 at 2 h; median 51 vs. 120 U/ml 5 h after initiation of therapy, p = 0.04). This did not result, however, in a decrease of indicators of neuronal damage. In conclusion, intravenous rifabutin was bactericidal in experimental pneumococcal meningitis. Provided that a well-tolerated i.v. formulation will be available it may qualify as a reserve antibiotic for pneumococcal meningitis, in particular when strains with a reduced sensitivity to beta-lactam antibiotics are the causative pathogens.

Animals↗