The effect of reversal of myoneural blockade on cerebrospinal fluid pressure following cerebral aneurysm surgery.

Drugs with a depolarizing action at the myoneural junction may cause a rise in intracranial pressure. Neostigmine, which is commonly used to reverse residual myoneural blockade, has a depolarizing action, and yet its effect on intracranial pressure is unknown. Lumbar cerebrospinal fluid pressure, which mirrors intracranial pressure, was determined in 12 patients undergoing cerebral aneurysm surgery. Cerebrospinal fluid pressure was measured during dense myoneural blockade and after its reversal with neostigmine. These effects on cerebrospinal fluid pressure were compared with those produced when the arterial partial pressure of carbon dioxide (PaCO2) rose from 4 to 5 kPa. After reversal of myoneural block, there was a small (non-significant) change in cerebrospinal fluid pressure from 3.6 to 4.3 kPa and a larger (significant) rise in cerebrospinal fluid pressure to 9.7 kPa when the PaCO2 was allowed to rise. In this group of patients, reversal of myoneural blockade with neostigmine causes no significant change in cerebrospinal fluid pressure.

Hepatocyte ultrastructure following exposure to aroclors and pure polychlorinated biphenyls.

Three agriculturally important minor species, the goat, rabbit, and duck, were exposed to various subclinical levels of pure polychlorinated biphenyls (PCBs) and/or PCB mixtures (Aroclors) for short periods of time. Upon sacrifice, liver samples were prepared for ultrastructural observation. Regardless of species, hepatocytes displayed qualitatively similar morphological responses to PCB exposure. At lower exposure levels, cellular changes included increased density of mitochondrial matrix and proliferation of endoplasmic reticulum. At higher exposure levels, degradative changes such as cytoplasmic loss and peripheralization of cytoplasm and organelles became more obvious. When compared quantitatively, it was obvious that goats were much more sensitive to PCB exposure than either rabbits or ducks. Goats showed extensive hepatocyte degradation (cytoplasmic and nucleoplasmic leaching) at exposures of 2 mg/kg body weight of Aroclor 1254. Such species-related differences in response to chlorinated biphenyls cautions against the use of single species animal models in xenobiotic exposure studies.

Transient ischaemic attack after spinal anaesthesia.

A case of transient ischaemic attack lasting 6 h occurred after spinal anaesthesia with bupivacaine. The level of sensory block was satisfactory and there was no significant hypotension. We discuss the possible cause of this previously undescribed complication.

Influence of DDT and PCBs in rabbits and goats as related to nucleic acid, protein and lipid metabolism.

Rabbits were administered DDT (10 mgQ/kg) and rabbits and goats were administered pure PCB compounds or PCB mixtures (25 mg/kg for rabbits and 5, 10 or 20 mg/kg for goats). All rabbits were also injected with ovalbumin and goats with Salmonella enteritidis-O antigen. Animals were sacrificed on day 21 when maximum antibody titer was obtained. Rabbits treated with 20 mg/kg DDT showed significantly reduced weight gain, feed consumption, weights of lung, liver and spleen, antiovalbumin synthesis in lung and spleen and maximum serum antibody titer. In addition, in the liver, protein, DNA and RNA contents and aminoacyl t-RNA activity were reduced. A decrease in serum protein was reflected in a decrease in albumin and gamma- and beta-globulin. Pure PCBs or PCB mixtures did not affect body weight, feed consumption or organ weights of rabbits. Protein and/or antiovalbumin synthesis increased in kidney, spleen and lung in rabbits after treatment with Aroclor 1242 or Aroclor 1254. PCB compounds decreased body weights but did not affect organ weights of goats except for a liver weight increase at 20 mg/kg for 2,4-DCBP, Aroclor 1268 and PCT. Aroclors 1242, 1254 and 1268 significantly decreased anti-Salmonella enteritidis synthesis in lymph node, spleen and bone marrow in goats at 20 mg/kg. However, at 5 mg/kg, a significant increase in antibody synthesis was observed. Ultrastructural evaluation of PCB-treated rabbits revealed little or no pathological change at these dose levels.

Ultrastructural effects of DDT on cells grown in vitro.

In vitro administration of DDT at 0.5 ppm, 10 ppm, and 50 ppm (0.5, 10 and 50 micrograms/ml culture medium) to HeLa S, human amnion (HA-FL), canine venereal tumor (CVT), canine kidney (MD-CK) and rat nephroma (RN) cells resulted in alterations of the ultrastructure of cells. Responses to the cytotoxic chemical compound were qualitatively and quantitatively similar among all mammalian cell lines tested. The tested cells exhibited dose-specific responses. Al low dose (0.5 ppm) rough endoplasmic reticulum and free ribosomes increased as did the number and size of smooth endoplasmic reticulum profiles. At higher doses (10 ppm and 50 ppm) there was indication of cellular degradation including mitochondrial disorganization, nuclear heterochromatic condensation and peripheralization, and increases in numbers of lysosomes, autophagic vacuoles and multivesicular bodies. This suggests that low level exposure to cytotoxic elements such as DDT initiates a repair and regeneration response from the cells while degenerative changes at higher exposure levels suggest less success with detoxification and possible irreversible cellular damage.

Intakes of vitamins and minerals by pregnant women with selected clinical symptoms.

Toxemia in pregnancy is characterized by a combination of at least two of the following clinical symptoms: hypertension, edema, and proteinuria. In this study the dietary intakes of young pregnant women attending a Maternal and Infant Care Program at Tuskegee Institute were evaluated for selected vitamins and minerals. Women with toxemia were identified, and women without toxemia served as controls. The toxemia group generally consumed lesser amounts of vitamins and minerals than the controls. However, both groups were deficient (less than two-thirds RDA) in calcium, magnesium, vitamin B6, vitamin B12, and thiamin. Milk, meat, and grains supplied an appreciable proportion of each vitamin except vitamin A, which was found primarily in the two vegetable groups. Meat and grains contained the greatest quantities of minerals, but milk provided a relatively good proportion of potassium, calcium, magnesium, and phosphorus. Anemia was not related to the incidence of toxemia. Women exhibiting anemia consumed smaller amounts of vitamins studied than did women without anemia.

Protein, amino acid, and caloric intakes of selected pregnant women.

Toxemia of pregnancy is characterized by a combination of at least two of the following clinical symptoms: hypertension, edema, and proteinuria. In three successive trials over three consecutive years, the dietary intakes of a selected number of young pregnant women attending a Maternal and Infant Care Clinic at Tuskegee Institute were evaluated for protein, amino acids, and total calories. Women with toxemia were identified, and women without toxemia served as controls. The toxemic group generally consumed more protein than the controls, but values were statistically significant only in the first trial. However, all essential amino acids were consumed in significantly greater amounts by the toxemic group. Protein and essential amino acids were consumed in adequate amounts (at least two-thirds of the RDA) by both groups but in amounts smaller than the national average. Non-essential amino acids were also consumed in adequate amounts, with the toxemic group consuming larger quantities than the controls. Caloric intakes were adequate for young pregnant women. The relationships of glucosuria and of toxemia to protein and amino acid intake were similar and were opposite to the relationship of anemia to protein and amino acid intake. Meats and grains contributed the greatest quantity of protein and amino acids to the diet in all groups. Data seem to imply that any relationship of protein and amino acids with toxemia of pregnancy is a complex one involving several possibly interrelated nutritional parameters.