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Biomedical subjects

C T Liu

Publications and source records attributed to C T Liu.

At least 73 records · Page 4Linked to original sources

Placentas in pregnancies complicated by maternal diabetes.

PDMs tend to be large and the size is generally in proportion to fetal size. Infarcts are both more numerous and more common in PDMs than in normal placentas. These reflect the in utero hypoxia found in IDMs. Placental infarcts are increased not only in cases of severe DM (classes D, F-R) but also mild and early DM (class A). We infer from this that maternal vascular disease may be present functionally long before pathologic changes can be detected by direct examination of vessels. More subtle evidence of hypoxia in PDMs, such as an increased number of syncytial knots, has been suggested by qualitative data but has not been confirmed by morphometric analysis. Other qualitative observations in PDMs include thickened basement membranes, flattened microvilli on trophoblasts, ectasia of capillaries and villous stromal edema; changes in intracellular organelles and structures include enlarged mitochondria, increased pinocytotic vesicles, and dilated profiles of endoplasmic reticulum. Quantitative morphometric analysis shows no differences between normal placentas and PDMs with regard to these changes. The transport and secretory functions of the placenta, especially important in pregnancy complicated by DM, are not addressed here. As our understanding of placental physiology enlarges, it will be useful to relate each function with its structural counterpart. Perhaps this review will in part provide rational data from which to proceed with the task.

Female↗

Two lethal chondrodysplasias with giant chondrocytes.

Two infants, each with a different form of sporadic lethal chondrodysplasia, had multinucleated giant chondrocytes in resting cartilage. Both patients also had severe laryngeal stenosis and normal chromosomes. The radiographic abnormalities in one patient conformed to the recently delineated entity, atelosteogenesis (spondylohumerofemoral hypoplasia or giant cell chondrodysplasia); the other patient had an unclassified type of spondyloepiphyseal dysplasia. The findings in these two patients and the previously reported observations in spondylohumerofemoral dysplasia confirm that chondrocytic giant cells are a causally nonspecific phenomenon.

Cartilage↗

Changes in body fluid compartments, tissue water and electrolyte distribution, and lipid concentrations in rhesus macaques with yellow fever.

Rhesus macaques were inoculated subcutaneously with 40 plaque-forming units of yellow fever (YF) virus. To identify pathophysiologic mechanisms of YF, rectal temperatures and evidence of viremia were observed daily; physiologic and biochemical changes were studied on postinoculation day (PID) 5. Marked viremia was detected on PID 2 through 5, and fever was first observed on PID 4. On PID 5, blood and plasma volumes and circulatory K+ values increased, whereas RBC volume, PCV, and plasma cholesterol concentration decreased. Total lipids (mainly triglycerides) accumulated in the liver of inoculated macaques; alterations in hepatic content of water, electrolytes, and trace metals were also observed. Certain parts of the CNS, skeletal muscle, skin, heart, diaphragm, and renal cortex were affected, with changes noticed in water, electrolyte, trace metal, and lipid concentrations. These tissue changes indicated that cellular metabolism was altered and that the transport mechanisms of cell membranes of certain tissues were modified by YF virus or the disease process caused by the virus. Terminal hypoglycemia (57.6 +/- 12.1 mg/dl) was observed. The YF-induced intracellular dehydration of the medulla oblongata at the later stage of illness may depress the cardiovascular and respiratory centers, thus contributing to death of rhesus macaques infected with YF virus.

Animals↗

Achondrogenesis: a review with special consideration of achondrogenesis type II (Langer-Saldino).

We describe two dwarfed infants with large head, short neck and chest, prominent abdomen, and short limbs. Both died neonatally. Radiographic and morphologic characteristics identified the Langer-Saldino form of achondrogenesis (type II). Review of type II achondrogenesis documented distinctive clinical and anthropometric manifestations (fewer stillbirths, longer survival time and gestation period, larger size of the baby, longer limbs, and characteristic craniofacial features) as compared with type I achondrogenesis (Parenti-Fraccaro).

Abnormalities, Multiple↗

Electrolyte metabolism in rhesus monkeys with experimental salmonella sepsis.

Prior investigations in the human indicate that alterations occur in electrolyte balance and serum concentration during infectious diseases. In order to explore these alterations in greater detail, electrolyte metabolism has been investigated in rhesus monkeys with a sublethal illness induced by intravenous inoculation with Salmonella typhimurium. The response to this illness was evaluated by a variety of measurements including serum and muscle electrolyte composition and renal function studies. In the animals with ad libitum dietary intake, a loss in muscle and serum potassium concentrations was evident within 24 h after inoculation. This was reflected in increased urinary potassium losses during the febrile phase of illness. Serum and muscle K concentrations returned to normal after 5 days of illness. Sodium and water content of muscle responded to infection in a more complex pattern. During the febrile phase, muscle sodium and water increased and sodium concentrations in serum and urine were elevated. During convalescence, renal retention of sodium was marked and overlapped the period of weight loss and the increased urine volume. This asynchrony in recovery of normal renal function appeared to be the cause of relatively large swings in plasma sodium concentrations during the early convalescent period. These investigations indicate that the altered serum concentrations in infectious diseases are the sum of renal and extrarenal factors controlling electrolyte metabolism, and that some of the most remarkable alterations occur during early convalescence as renal function returns to normal.

Animals↗

Effect of Streptococcus pneumoniae infection in rats on hepatic water content, electrolyte concentration, and chemical composition.

Total hepatic water content, dry weight, protein, lipid, carbohydrate, RNA, DNA, and electrolyte concentrations were determined in control and Streptococcus pneumoniae-infected rats. During infection, there was a significant (P = 0.001) increase in total liver weight. This increase was the result of increased total liver water content and increased total liver dry weight. Intracellular water content, diameter of hepatocytes, and all measured constituents of hepatic dry weight, excluding DNA, increased significantly (P varied from 0.05-0.001) during infection. Concentrations of liver Na+ and Cl- increased significantly (P varied from 0.05-0.005), whereas the concentration of liver K+ decreased significantly (P = 0.01). Seemingly, there is an enlargement of hepatocytes due to increased intracellular water and increased dry weight during pneumococcal infection in the rat. The mechanism of these liver changes may be due, in part, to a shift of Na+ and K+ across liver cell plasma membranes.

Animals↗

Placental morphometric studies in diabetic pregnancies.

Placentae from 20 pregnancies complicated by diabetes mellitus were, by morphometric analyses, similar to 20 placentae from normal patients. Since the average gestation in this study was 1.5 weeks less in the PDM group, accelerated maturity rather than retarded villous development may be inferred. Based on maternal HbAIC determinations, neonatal morbidity and macrosomia, the morphometric similarities of PDM to control placentae in this series do not appear to be explained by normalization of maternal blood glucose levels in the diabetic group.

Adult↗

Diurnal changes in rectal and body surface temperatures of conscious, chair-restrained rhesus macaques.

A system has been established for continuous recording of rectal and body surface temperatures in conscious, chair-restrained rhesus macaques. Diurnal changes in rectal temperature and body surface temperatures of head, back, abdomen, and inner thigh were recorded for 24 hours under conditions of intermittent or constant light. When lights were on for 8 hours (0800 to 1600 hours) and off for 16 hours, maximal rectal temperatures (37.6 +/- 0.3 C) were observed at 0900 hours, whereas minimal rectal temperatures (36.7 +/- 0.4 C) were demonstrated between 0200 and 0400 hours. Mean rectal temperatures varied 0.9 C during a 24-hour period. A trend of diurnal changes in body surface temperatures was also observed with low surface temperatures recorded between 0400 and 0800 hours. The surface temperatures (33.8 to 36.5 C) were markedly lower than rectal temperatures (36.7 to 37.6 C) under the same experimental conditions. When macaques were subjected to constant light, high rectal temperatures were recorded between 0900 and 1700 hours and low rectal temperatures were observed between 2400 and 0300 hours with a mean variation of 0.7 C (36.3 +/- 0.15 to 37.0 +/- 0.2). Diurnal body surface temperature changes during constant light were less pronounced than those of rectal temperatures. Furthermore, low surface temperatures of abdomen and inner thigh recorded between 0200 and 0800 hours were similar to those obtained with macaques exposed to the light-dark condition.

Animals↗